1.INTRODUCTION

Tunnel

FIG: 1

A tunnel is an underground passageway, completely enclosed

except for openings for egress, commonly at each end.

A tunnel may be for foot or vehicular road traffic, for rail traffic,

or for a canal. Some tunnels are aqueducts to supply water for consumption or for

hydroelectric stations or are sewers. Other uses include routing power or

telecommunication cables, some are to permit wildlife such as European badgers to

cross highways. Secret tunnels have given entrance to or escape from an area, such

as the Cu Chi Tunnels or the smuggling tunnels in the Gaza Strip which connect it to

Egypt. Some tunnels are not for transport at all but rather, are fortifications, for

example Mittelwerk and Cheyenne Mountain.

In the United Kingdom, a pedestrian tunnel or other underpass

beneath a road is called a underpass subway. In the United States that term now

means an underground rapid transit system.

The central part of a rapid transit network is usually built in

tunnels. Rail station platforms may be connected by pedestrian tunnels or by foot

bridges.

Railroads

The work on a high-speed line (ligne à grande vitesse, or LGV)

begins with earth moving. The trackbed is carved into the landscape, using scrapers,

graders, bulldozers and other heavy machinery. All fixed structures are built; these

include bridges, flyovers, culverts, game tunnels, and the like. Drainage facilities,

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most notably the large ditches on either side of the trackbed, are constructed. Supply

bases are established near the end of the high-speed tracks, where crews will form

work trains to carry rail, sleepers and other supplies to

the work site.

FIG: 2

Next, a layer of compact gravel is spread on the trackbed. This,

after being compacted by rollers, provides an adequate surface for vehicles with

tyres. TGV tracklaying then proceeds. The tracklaying process is not particularly

specialized to high-speed lines; the same general technique is applicable to any track

that uses continuous welded rail. The steps outlined below are used around the

world in modern tracklaying. TGV track, however, answers to stringent requirements

that dictate materials, dimensions and tolerances.

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` Chapter 1:

1.1 Construction

FIG: 1.1

Cut-and-cover constructions of the Paris Métro in France

Tunnels are dug in types of materials varying from soft clay to

hard rock. The method of tunnel construction depends on such factors as the ground

conditions, the ground water conditions, the length and diameter of the tunnel drive,

the depth of the tunnel, the logistics of supporting the tunnel excavation, the final

use and shape of the tunnel and appropriate risk management.

There are three basic types of tunnel construction in common use:

Cut and cover tunnels, constructed in a shallow trench and then covered over.

Bored tunnels, constructed in situ, without removing the ground above. They

are usually of circular or horseshoe cross-section.

Immersed tube tunnels, sunk into a body of water and sit on, or are buried just

under, its bed.

1.1.1Usage limitations

A tunnel is relatively long and narrow; in general the length is

more (usually much more) than twice the diameter. Some hold a tunnel to be at least

0.160 kilometres (0.10 mi) long and call shorter passageways by such terms as an

"underpass" or a "chute". For example, the underpass beneath Yahata Station in

Kitakyushu, Japan is 0.130 km long (0.081 mi) and so might not be considered a

tunnel.

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1.1.2 Geotechnical investigation

A tunnel project must start with a comprehensive investigation of

ground conditions by collecting samples from boreholes and by other geophysical

techniques. An informed choice can then be made of machinery and methods for

excavation and ground support, which will reduce the risk of encountering

unforeseen ground conditions. In planning the route the horizontal and vertical

alignments will make use of the best ground and water conditions.

In some cases conventional desk and site studies yield insufficient

information to assess such factors as the blocky nature of rocks, the exact location of

fault zones, or the stand-up times of softer ground. This may be a particular concern

in large diameter tunnels. To give more information a pilot tunnel, or drift, may be

driven ahead of the main drive. This smaller diameter tunnel will be easier to support

should unexpected conditions be met, and will be incorporated in the final tunnel.

Alternatively, horizontal boreholes may sometimes be drilled ahead of the advancing

tunnel face.

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`

Chapter 2: Techniques

2.1 Cut-and-cover

Cut-and-cover is a simple method of construction for shallow

tunnels where a trench is excavated and roofed over with an overhead support

system strong enough to carry the load of what is to be built above the tunnel. Two

basic forms of cut-and-cover tunnelling are available:

Bottom-up method: A trench is excavated, with ground support as necessary,

and the tunnel is constructed in it. The tunnel may be of in situ concrete,

precast concrete, precast arches,or corrugated steel arches; in early days

brickwork was used. The trench is then carefully back-filled and the surface is

reinstated.

Top-down method: Here side support walls and capping beams are constructed

from ground level by such methods as slurry walling, or contiguous bored

piling. Then a shallow excavation allows making the tunnel roof of precast

beams or in situ concrete. The surface is then reinstated except for access

openings. This allows early reinstatement of roadways, services and other

surface features. Excavation then takes place under the permanent tunnel roof,

and the base slab is constructed.

Shallow tunnels are often of the cut-and-cover type (if under

water, of the immersed-tube type), while deep tunnels are excavated, often using a

tunnelling shield. For intermediate levels, both methods are possible.

Large cut-and-cover boxes are often used for underground

metro stations, such as Canary Wharf tube station in London. This construction form

generally has two levels, which allows economical arrangements for ticket hall,

station platforms, passenger access and emergency egress, ventilation and smoke

control, staff rooms, and equipment rooms. The interior of Canary Wharf station has

been likened to an underground cathedral, owing to the sheer size of the excavation.

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This contrasts with most traditional stations on London Underground, where bored

tunnels were used for stations and passenger access.

2.2 Clay-kicking

Clay-kicking is a specialised method developed in the United

Kingdom, of manually digging tunnels in strong clay-based soil structures. Unlike

previous manual methods of using mattocks which relied on the soil structure to be

hard, clay-kicking was relatively silent and hence did not harm soft clay based

structures.

The clay-kicker lies on a plank at a 45degree angle away from

the working face, and inserts a tool with a cup-like rounded end with his feet.

Turning the tool with his hands, he extracts a section of soil, which is then placed on

the waste extract.

Regularly used in Victorian civil engineering, the methods

found favour in the renewal of the United Kingdom's then ancient sewerage systems,

by not having to remove all property or infrastructure to create an effective small

tunnel system. During the First World War, the system was successfully deployed by

the Royal Engineer tunnelling companies to deploy large military mines beneath

enemy German Empire lines. The method was virtually silent not susceptible to

listening methods of detection.

2.3 Boring machines

Tunnel boring machine

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FIG: 2.1

A tunnel boring machine that was used at Yucca Mountain, Nevada,

United States

Tunnel boring machines (TBMs) and associated back-up systems

are used to highly automate the entire tunneling process, reducing tunneling costs.

Tunnel boring in certain predominantly urban applications, is

viewed as quick and cost effective alternative to laying surface rails and roads.

Expensive compulsory purchase of buildings and land with potentially lengthy

planning inquiries is eliminated.

There are a variety of TBMs that can operate in a variety of

conditions, from hard rock to soft water-bearing ground. Some types of TBMs,

bentonite slurry and earth-pressure balance machines, have pressurised

compartments at the front end, allowing them to be used in difficult conditions below

the water table. This pressurizes the ground ahead of the TBM cutter head to

balance the water pressure. The operators work in normal air pressure behind the

pressurised compartment, but may occasionally have to enter that compartment to

renew or repair the cutters. This requires special precautions, such as local ground

treatment or halting the TBM at a position free from water. Despite these difficulties,

TBMs are now preferred to the older method of tunneling in compressed air, with an

air lock/decompression chamber some way back from the TBM, which required

operators to work in high pressure and go through decompression procedures at the

end of their shifts, much like divers.

In February 2010, Aker Wirth delivered a TBM to Switzerland,

for the expansion of Linth Limmern Power Plant in Switzerland. The borehole has a

diameter of 8.03 metres (26.3 ft).[2] The TBM used for digging the 57-kilometre

(35 mi) Gotthard Base Tunnel, in Switzerland, has a diameter of about 9 metres

(30 ft). A larger TBM was built to bore the Green Heart Tunnel (Dutch: Tunnel

Groene Hart) as part of the HSL-Zuid in the Netherlands, with a diameter of

14.87 metres (48.8 ft).[3] This in turn was superseded by the Madrid M30 ringroad,

Spain, and the Chong Ming tunnels in Shanghai, China. All of these machines were

built at least partly by Herrenknecht.

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2.4 Shafts

A shaft is sometimes necessary for a tunnel project. They are

usually circular and go straight down until they reach the level at which the tunnel is

going to be built. A shaft normally has concrete walls and is built just like it is going

to be permanent. Once they are built the Tunnel Boring Machines are lowered to the

bottom and excavation can start. Shafts are the main entrance in and out of the

tunnel until the project is completed. Sometimes if a tunnel is going to be long there

will be multiple shafts at various locations so that entrance into the tunnel is closer

to the unexcavated area.

2.4.1 Other key factors

Stand-up time is the amount of time a tunnel will support itself without any

added structures. Knowing this time allows the engineers to determine how

much can be excavated before support is needed. The longer the stand-up time

is the faster the excavating will go. Generally certain configurations of rock

and clay will have the greatest stand-up time, and sand and fine soils will have

a much lower stand-up time.

Groundwater control is very important in tunnel construction. If there is water

leaking into the tunnel stand-up time will be greatly decreased. If there is

water leaking into the shaft it will become unstable and will not be safe to work

in. To stop this from happening there are a few common methods. One of the

most effective is ground freezing. To do this pipes are inserted into the ground

surrounding the shaft and are cooled until they freeze. This freezes the ground

around each pipe until the whole shaft is surrounded frozen soil, keeping water

out. The most common method is to install pipes into the ground and to simply

pump the water out. This works for tunnels and shafts.

Tunnel shape is very important in determining stand-up time. The force from

gravity is straight down on a tunnel, so if the tunnel is wider than it is high it

will have a harder time supporting itself decreasing its stand-up time. If a

tunnel is higher than it is wide the stand up time will increase making the

project easier. The hardest shape to support itself is a square or rectangular

tunnel. The forces have a harder time being redirected around the tunnel

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` making it extremely hard to support itself. This of course all depends what the

material of the ground is.

2.5 Sprayed concrete techniques

The New Austrian Tunneling Method (NATM) was developed in the

1960s, and is the best known of a number of engineering solutions that use

calculated and empirical real-time measurements to provide optimised safe support

to the tunnel lining. The main idea of this method is to use the geological stress of

the surrounding rock mass to stabilize the tunnel itself, by allowing a measured

relaxation and stress reassignment into the surrounding rock to prevent full loads

becoming imposed on the introduced support measures. Based on geotechnical

measurements, an optimal cross section is computed. The excavation is immediately

protected by a layer of sprayed concrete, commonly referred to as shotcrete, after

excavation. Other support measures could include steel arches, rockbolts and mesh.

Technological developments in sprayed concrete technology have resulted in steel

and polypropylene fibres being added to the concrete mix to improve lining strength.

This creates a natural load-bearing ring, which minimizes the rock's deformation.

FIG: 2.2

Illowra Battery utility tunnel, Port Kembla. One of many bunkers south

of Sydney.

By special monitoring the NATM method is very flexible, even at

surprising changes of the geomechanical rock consistency during the tunneling

work. The measured rock properties lead to appropriate tools for tunnel

strengthening. In the last decades also soft ground excavations up to 10 kilometres

(6.2 mi) became usual.

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2.6 Pipe jacking

Pipe Jacking , also known as pipejacking or pipe-jacking, is a

method of tunnel construction where hydraulic jacks are used to push specially made

pipes through the ground behind a tunnel boring machine or shield. This technique is

commonly used to create tunnels under existing structures, such as roads or

railways. Tunnels constructed by pipe jacking are normally small diameter tunnels

with a maximum size of around 2.4m.

2.7 Box jacking

Box jacking is similar to pipe jacking, but instead of jacking tubes, a

box shaped tunnel is used. Jacked boxes can be a much larger span than a pipe jack

with the span of some box jacks in excess of 20m. A cutting head is normally used at

the front of the box being jacked and excavation is normally by excavator from within

the box.

2.8 Underwater tunnels

There are also several approaches to underwater tunnels, the two most

common being bored tunnels or immersed tubes. Submerged floating tunnels are

another approach that has not been constructed.

Other

2.8.1 Other tunneling methods include:

Drilling and blasting

Slurry-shield machine

Wall-cover construction method.

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`

2.8.2 Costs and cost overruns of tunnels

Tunnels are costly and generally more costly than bridges. Large

cost overruns are common in tunnel construction.

2.9 Choice of tunnels vs. bridges

For water crossings, a tunnel is generally more costly to

construct than a bridge. Navigational considerations may limit the use of high

bridges or drawbridge spans intersecting with shipping channels, necessitating a

tunnel.

Bridges usually require a larger footprint on each shore than

tunnels. There are actually more codes to follow with bridges than with tunnels. In

areas with expensive real estate, such as Manhattan and urban Hong Kong, this is a

strong factor in tunnels' favor. Boston's Big Dig project replaced elevated roadways

with a tunnel system to increase traffic capacity, hide traffic, reclaim land,

redecorate, and reunite the city with the waterfront.

The 1934 Queensway Road Tunnel under the River Mersey at

Liverpool, was chosen over a massively high bridge for defence reasons. It was

feared aircraft could destroy a bridge in times of war. Maintenance costs of a

massive bridge to allow the world's largest ships navigate under was considered

higher than a tunnel. Similar conclusions were met for the 1971 Kingsway Tunnel

under the River Mersey.

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FIG: 2.3

The Queens–Midtown Tunnel in New York City serves as an example of a water-

crossing tunnel built instead of a bridge.

Examples of water-crossing tunnels built instead of bridges

include the Holland Tunnel, Queens-Midtown Tunnel and Lincoln Tunnel between

New Jersey and Manhattan in New York City, and the Elizabeth River tunnels

between Norfolk and Portsmouth, Virginia, the 1934 River Mersey road Queensway

Tunnel and the Western Scheldt Tunnel, Zeeland, Netherlands.

Other reasons for choosing a tunnel instead of a bridge include

avoiding difficulties with tides, weather and shipping during construction (as in the

51.5-kilometre or 32.0 mi Channel Tunnel), aesthetic reasons (preserving the above-

ground view, landscape, and scenery), and also for weight capacity reasons (it may

be more feasible to build a tunnel than a sufficiently strong bridge). Some water

crossings are a mixture of bridges and tunnels, such as the Denmark to Sweden link

and the Chesapeake Bay Bridge-Tunnel in the eastern United States.

There are particular hazards with tunnels, especially from vehicle

fires when combustion gases can asphyxiate users, as happened at the Gotthard

Road Tunnel in Switzerland in 2001. One of the worst railway disasters ever, the

Balvano train disaster, was caused by a train stalling in the Armi tunnel in Italy in

1944, killing 426 passengers.

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`

Chapter 3: Variant tunnel types

3.1 Double-deck tunnel

Some tunnels are double-deck, for example the two major

segments of the San Francisco – Oakland Bay Bridge (completed in 1936) are linked

by a double-deck tunnel, once the largest diameter tunnel in the world. At

construction this was a combination bidirectional rail and truck pathway on the

lower deck with automobiles above, now converted to one-way road vehicle traffic on

each deck.

A recent double-decker tunnel with both decks for motor vehicles is the Fuxing Road

Tunnel in Shanghai, China. Cars travel on the two-lane upper deck and heavier

vehicles on the single-lane lower.

Multipurpose tunnel are tunnels that have more than one purpose. The SMART

Tunnel in Malaysia is the first multipurpose tunnel in the world, as it is used both to

control traffic and flood in Kuala Lumpur.

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3.2 Artificial tunnels

FIG: 3.1

The 19th century Dark Gate in Esztergom, Hungary.

Overbridges can sometimes be built by covering a road or river or

railway with brick or still arches, and then levelling the surface with earth. In railway

parlance, a surface-level track which has been built or covered over is normally

called a covered way.

Snow sheds are a kind of artificial tunnel built to protect a railway from avalanches

of snow. Similarly the Stanwell Park, New South Wales steel tunnel, on the South

Coast railway line, protects the line from rockfalls.

Common utility ducts are man-made tunnels created to carry two or more utility lines

underground. Through co-location of different utilities in one tunnel, organizations

are able to reduce the costs of building and maintaining utilities.

3.3 Hazards

Owing to the enclosed space of a tunnel, fires can have very serious

effects on users. The main dangers are gas and smoke production, with low

concentrations of carbon monoxide being highly toxic. Fires killed 11 people in the

Gotthard tunnel fire of 2001 for example, all of the victims succumbing to smoke and

gas inhalation. Over 400 passengers died in the Balvano train disaster in Italy in

1944, when the locomotive halted in a long tunnel. Carbon monoxide poisoning was

the main cause of the horrifying death rate.

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3.4 Examples of tunnels

In history

FIG: 3.2

A short section remains of the 1836 Edge Hill to Lime Street tunnel in Liverpool. This

is the oldest used rail tunnel in the world. A tilting train passes through the tunnel.

FIG: 3.3

The World's oldest underwater tunnel is

rumored to be the Terelek kaya tüneli under Kızıl River, a little south of the towns of

Boyabat and Duragan in Turkey. Estimated to have been built more than 2000 years

ago (possibly 5000), it is assumed to have had a defence purpose.

The qanat or kareez of Persia is a water management system used to provide a

reliable supply of water to human settlements or for irrigation in hot, arid and

semi-arid climates. The oldest and largest known qanat is in the Iranian city of

Gonabad, which after 2700 years, still provides drinking and agricultural water

to nearly 40,000 people. Its main well depth is more than 360 m (1,180 ft), and

its length is 45 km (28 mi).

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` The Eupalinian aqueduct on the island of Samos (North Aegean, Greece). Built

in 520 BC by the ancient Greek engineer Eupalinos of Megara. Eupalinos

organised the work so that the tunnel was begun from both sides of mount

Kastro. The two teams advanced simultaneously and met in the middle with

excellent accuracy, something that was extremely difficult in that time. The

aqueduct was of utmost defensive importance, since it ran underground, and it

was not easily found by an enemy who could otherwise cut off the water supply

to Pythagoreion, the ancient capital of Samos. The tunnel's existence was

recorded by Herodotus (as was the mole and harbour, and the third wonder of

the island, the great temple to Hera, thought by many to be the largest in the

Greek world). The precise location of the tunnel was only re-established in the

19th century by German archaeologists. The tunnel proper is 1,030 m long

(3,380 ft) and visitors can still enter it Eupalinos tunnel.

The Via Flaminia, an important Roman road, penetrated the Furlo pass in the

Apennines through a tunnel which emperor Vespasian had ordered built in 76-

77. A modern road, the SS 3 Flaminia, still uses this tunnel, which had a

precursor dating back to the 3rd century BC; remnants of this earlier tunnel

(one of the first road tunnels) are also still visible.

Sapperton Canal Tunnel on the Thames and Severn Canal in England, dug

through hills, which opened in 1789, was 3.5 km (2.2 mi) long and allowed boat

transport of coal and other goods. Above it runs the Sapperton Long Tunnel

which carries the "Golden Valley" railway line between Swindon and

Gloucester.

The 1796 Stoddart Tunnel in Chapel-en-le-Frith in Derbyshire is reputed to be

the oldest rail tunnel in the world. Rail wagons were horse-drawn.

The tunnel was created for the first true steam locomotive, from Penydarren to

Abercynon. The Penydarren locomotive was built by Richard Trevithick. The

locomotive made the historic journey from Penydarren to Abercynon in 1804.

Part of this tunnel can still be seen at Pentrebach, Merthyr Tydfil, Wales. This

is arguably the oldest railway tunnel in the world, for self-propelled steam

engines on rails.

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` The Montgomery Bell Tunnel in Tennessee, a 88 m (289 ft), high water

diversion tunnel, 4.50-×-2.45 m high (15-×-8.0 ft), to power a water wheel, was

built by slave labour in 1819, being the first full-scale tunnel in North America.

Crown Street Station , Liverpool, 1829. Built by George Stephenson, a single

track tunnel 291 yd long (266 m) was bored from Edge Hill to Crown Street to

serve the world's first passenger railway station. The station was abandoned in

1836 being too far from Liverpool city centre, with the area converted for

freight use. Closed down in 1972, the tunnel is disused. However it is the

oldest rail tunnel running under streets in the world. [1]

The 1.26 mile (2.03 km) 1829 Wapping Tunnel in Liverpool, England, was the

first rail tunnel bored under a metropolis. Currently disused since 1972.

Having two tracks, the tunnel runs from Edge Hill in the east of the city to the

south end Liverpool docks being used only for freight. The tunnel is still in

excellent condition and is being considered for reuse by Merseyrail rapid

transit rail system, with maybe an underground station cut into the tunnel. The

river portal is opposite the new Liverpool Arena being ideal for a serving

station. If reused it will be the oldest used underground rail tunnel in the world

and oldest part of any underground metro system.

1836, Lime St Station tunnel, Liverpool. A two track rail tunnel, 1.13 miles

(1,811 m) long was bored under a metropolis from Edge Hill in the east of the

city to Lime Street. In the 1880s the tunnel was converted to a deep cutting

four tracks wide. The only occurrence of a tunnel being removed. A very short

section of the original tunnel still exists at Edge Hill station making this the

oldest rail tunnel in the world still in use, and the oldest in use under a street,

albeit only one street and one building.

Box Tunnel in England, which opened in 1841, was the longest railway tunnel

in the world at the time of construction. It was dug and has a length of 2.9 km

(1.8 mi).

The 0.75 mile long 1842 Prince of Wales Tunnel, in Shildon near Darlington,

England, is the oldest sizable tunnel in the world still in use under a

settlement.

The Thames Tunnel, built by Marc Isambard Brunel and his son Isambard

Kingdom Brunel and opened in 1843, was the first underwater tunnel and the

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` first to use a tunnelling shield. Originally used as a foot-tunnel, it was a part of

the East London Line of the London Underground until 2007, being the oldest

section of the system. From 2010 the tunnel becomes a part of the London

Overground system.

The 2.07 miles (3.34 km) Victoria Tunnel in Liverpool, opened in 1848, was

bored under a metropolis. Initially used only for rail freight and later freight

and passengers serving the Liverpool ship liner terminal, the tunnel runs from

Edge Hill in the east of the city to the north end Liverpool docks. Used until

1972 it is still in excellent condition, being considered for reuse by the

Merseyrail rapid transit rail system. Stations being cut into the tunnel are

being considered. Also, reuse by a monorail system from the proposed

Liverpool Waters redevelopment of Liverpool's Central Docks has been

proposed.

The oldest underground sections of the London Underground were built using

the cut-and-cover method in the 1860s. The Metropolitan, Hammersmith &

City, Circle and District lines were the first to prove the success of a metro or

subway system. Dating from 1863, Baker Street station is the oldest

underground station in the world.

The 1882 Col de Tende Road Tunnel, at 3182 metres long, was one of the first

long road tunnels under a pass, running between France and Italy.

The Mersey Railway tunnel opened in 1886 running from Liverpool to

Birkenhead under the River Mersey. The Mersey Railway was the world's first

deep-level underground railway. By 1892 the extensions on land from

Birkenhead Park station to Liverpool Central Low level station gave a tunnel

3.12 miles (5029 m) in length. The under river section is 0.75 miles in length,

being the longest underwater tunnel in world in January 1886.

The rail Severn Tunnel was opened in late 1886, at 4 miles 624 yd (7,008 m)

long, although only 2¼ miles (3.62 km) of the tunnel is actually under the river.

The tunnel replaced the Mersey Railway tunnel's longest under water record,

which it held for less than a year.

James Greathead , in constructing the City & South London Railway tunnel

beneath the Thames, opened in 1890, brought together three key elements of

tunnel construction under water: 1) shield method of excavation; 2) permanent

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` cast iron tunnel lining; 3) construction in a compressed air environment to

inhibit water flowing through soft ground material into the tunnel heading.[9]

St. Clair Tunnel , also opened later in 1890, linked the elements of the

Greathead tunnels on a larger scale.[9]

The 1927 Holland Tunnel was the first underwater tunnel designed for

automobiles. This fact required a novel ventilation system.

Longest

The Delaware Aqueduct in New York USA is the longest tunnel, of any type, in

the world at 137 km (85 mi). It is drilled through solid rock.

The Gotthard Base Tunnel is the longest rail tunnel in the world at 57 km

(35 mi). It will be totally completed in 2017.

The Seikan Tunnel in Japan was the longest rail tunnel in the world at 53.9 km

(33.5 mi), of which 23.3 km (14.5 mi) is under the sea.

The Channel Tunnel between France and the United Kingdom under the

English Channel is the second-longest, with a total length of 50 km (31 mi), of

which 39 km (24 mi) is under the sea.

The Lötschberg Base Tunnel opened in June 2007 in Switzerland was the

longest land rail tunnel, with a total of 34.5 km (21.4 mi).

The Lærdal Tunnel in Norway from Lærdal to Aurland is the world's longest

road tunnel, intended for cars and similar vehicles, at 24.5 km (15.2 mi).

The Zhongnanshan Tunnel in People's Republic of China opened in January

2007 is the world's second longest highway tunnel and the longest road tunnel

in Asia, at 18 km (11 mi).

The longest canal tunnel is the Rove Tunnel in France, over 7.12 km (4.42 mi)

long.

Notable

The Lincoln Tunnel between New Jersey and New York is one of the busiest

vehicular tunnels in the United States, at 120,000 vehicles/day.

The Central Artery Tunnel in Boston carries approximately 200,000

vehicles/day.

19D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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` The Fredhälls Tunnel in Stockholm, Sweden, and the New Elbe Tunnel in

Hamburg, Germany, both with around 150,000 vehicles a day, two of the most

trafficked tunnels in the world.

Gerrards Cross tunnel in Britain is notable in that it is being built over a

railway cutting that was dug in the early part of the 20th Century. Thus,

arguably, making it the tunnel longest in construction by the cut and cover

method. When complete a branch of the Tesco supermarket chain will occupy

the space above the railway tunnel.

Williamson's tunnels in Liverpool, built by a wealthy eccentric are probably the

largest underground folly in the world.

New York City Water Tunnel No. 3 [2] , started in 1970, has an expected

completion date of 2020.

The Chicago Deep Tunnel Project is a network of 175 km (109 mi) of tunnels

designed to reduce flooding in the Chicago area. Started in the mid 1970s, the

project is due to be completed in 2019.

Moffat Tunnel in Colorado straddles the Continental Divide. The tunnel is

6.2 mi (10.0 km) long and at 9,239 ft (2,816 m) above sea level is the highest

railroad tunnel in the United States.

The Fenghuoshan tunnel on Qinghai-Tibet railway is the world's highest

railway tunnel, about 4,905 m (16,093 ft) above sea level.

The La Linea Tunnel in Colombia, will be (2013) the longest, 8.58 km (5.33 mi),

mountain tunnel in South America. It crosses beneath a mountain at 2,500 m

(8,202.1 ft) above sea level with six lanes and it has a parallel emergency

tunnel. The tunnel is subject to serious groundwater pressure. The tunnel,

which is currently under construction, will link Bogotá and its urban area with

the coffee-growing region and with the main port on the Colombian Pacific

coast.

The Honningsvåg Tunnel (4.443 km (2.76 mi) long) on European route E69 in

Norway is the world's northernmost road tunnel, except for mines (which exist

on Svalbard).

The Eiksund Tunnel [3] on national road Rv 653 in Norway is the world's

deepest subsea road tunnel (7,776 m long, with deepest point at -287 metres

below the sea level, opened in feb. 2008)

20D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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Other uses

Excavation techniques, as well as the construction of

underground bunkers and other habitable areas, are often associated with military

use during armed conflict, or civilian responses to threat of attack. The use of

tunnels for mining is called drift mining. One of the strangest uses of a tunnel was

for the storage of chemical weapons.

3.5 Natural tunnels

Lava tubes are partially empty, cave-like conduits underground, formed during

volcanic eruptions by flowing and cooling lava.

Natural Tunnel State Park (Virginia, USA) features an 850-foot (259 m) natural

tunnel, really a limestone cave, that has been used as a railroad tunnel since

1890.

Punarjani Guha Kerala, India. Hindus believe that crawling through the tunnel

(which they believe was created by a Hindu god) from one end to the other will

wash away all of one’s sins and thus attain rebirth, although only men are

permitted to crawl through the cave.

Small "snow tunnels" are created by voles, chipmunks and other rodents for

protection and access to food sources. For more information regarding tunnels

built by animals, see Burrow

3.6 Temporary way

During construction of a tunnel it is often convenient to install a

temporary railway particularly to remove spoil. This temporary railway is often

narrow gauge so that it can be double track, which facilitates the operation of empty

and loaded trains at the same time. The temporary way is replaced by the permanent

way at completion, thus explaining the term Perway.

3.7 Enlargement

The vehicles using a tunnel can outgrow it, requiring replacement or

enlargement. The original single line Gib Tunnel near Mittagong was replaced with a

21D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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double line tunnel, with the original tunnel used for growing mushrooms.[citation needed]

The Rhyndaston Tunnel was enlarged using a borrowed Tunnel Boring Machine so as

to be able to take ISO containers.

The 1836 Lime Street two track 1 mile tunnel from Edge Hill to Lime

Street in Liverpool was totally removed, apart from a short 50 metre section at Edge

Hill. Four tracks were required. The tunnel was converted into a very deep 4 track

open cutting. However, short larger 4 track tunnels were left in some parts of the

run. Train services were not interrupted as the work progressed. Photos of the work

in progress: There are other occurrences of tunnels being replaced by open cuts, for

example, the Auburn Tunnel.

3.8 Location

Most of the tunnels listed below are located in the Western Ghats,

the only mountain range in the country that has good railway connectivity. There are

longer tunnels that are under construction in the Himalayas in Jammu and Kashmir,

as part of the USBRL Project.`

Name

(numbe

r on

route)

Length Between stations State

Zonal

Railwa

y

Year of

commission

ing

Coordinat

es

Karbude

(T-35)

6,506 met

res

(21,345

ft)

Ukshi BhokeMaharas

htra

Konkan

Railwa

y

1997

17°6′9″N

73°24′59″E

/ 17.1025°

N

73.41639°

E

Nathuw

adi (T-6)

4,389 met

res

(14,400 ft

)

Karanjad

i

Diwan

Khavati

Maharas

htra

Konkan

Railwa

y

1997

17°53′37″

N

73°23′14″E

22D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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` / 17.89361

°N

73.38722°

E

Tike (T-

39)

4,077 met

res

(13,376 ft

)

Ratnagir

iNivasar

Maharas

htra

Konkan

Railwa

y

1997

16°58′48″

N

73°23′42″E

/ 16.98°N

73.395°E

Berdewa

di (T-49)

4,000 met

res

(13,000 ft

)

Adavali VilawadeMaharas

htra

Konkan

Railwa

y

1997

16°53′43″

N

73°36′22″E

/ 16.89528

°N

73.60611°

E

Savarde

(T-17)

3,429 met

res

(11,250 ft

)

Kamathe SavardeMaharas

htra

Konkan

Railwa

y

1997

17°27′35″

N

73°31′19″E

/ 17.45972

°N

73.52194°

E

Sangar

(T-4)

2,445 met

res

(8,022 ft)

Sangar Manwal

Jammu

and

Kashmir

Northe

rn

Railwa

y

2005

23D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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Monkey

Hill (T-

25C)

2,156 met

res

(7,073 ft)

Karjat KhandalaMaharas

htra

Central

Railwa

y

1982

Aravali

(T-21)

2,100 met

res

(6,900 ft)

AravaliSangamesh

war

Maharas

htra

Konkan

Railwa

y

1997

Chiplun

(T-16)

2,033 met

res

(6,670 ft)

Chiplun KamatheMaharas

htra

Konkan

Railwa

y

199717°29′45″

N

73°31′50″E

TABLE: 1

Chapter 4:

4.1 Railroad Construction

24D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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4.1.1 LGV construction is the process by which the land on which TGV trains

are to run is prepared for their use, involving carving the trackbed and laying the

track. It is similar to the building of standard railway lines, but there are differences.

In particular, construction process is more precise in order for the track to be

suitable for regular use at 300 km/h (186 mph). The quality of construction was put

to the test in particular during the TGV world speed record runs on the LGV

Atlantique; the track was used at over 500 km/h (310 mph) without suffering

significant damage. This contrasts with previous French world rail speed record

attempts which resulted in severe deformation of the track.

4.1.2 Preparing the trackbed

The work on a high-speed line (ligne à grande vitesse, or LGV)

begins with earth moving. The trackbed is carved into the landscape, using scrapers,

graders, bulldozers and other heavy machinery. All fixed structures are built; these

include bridges, flyovers, culverts, game tunnels, and the like. Drainage facilities,

most notably the large ditches on either side of the trackbed, are constructed. Supply

bases are established near the end of the high-speed tracks, where crews will form

work trains to carry rail, sleepers and other supplies to the work site.

Next, a layer of compact gravel is spread on the trackbed.

This, after being compacted by rollers, provides an adequate surface for vehicles

with tyres. TGV tracklaying then proceeds. The tracklaying process is not

particularly specialized to high-speed lines; the same general technique is applicable

to any track that uses continuous welded rail. The steps outlined below are used

around the world in modern tracklaying. TGV track, however, answers to stringent

requirements that dictate materials, dimensions and tolerances.

4.1.3 Laying the track

To begin laying track, a gantry crane that rides on rubber

tires is used to lay down panels of prefabricated track. These are laid roughly in the

location where one of the tracks will be built (all LGVs have two tracks). Each panel

25D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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is 18 metres (60 feet) long, and rests on wooden sleepers. No ballast is used at this

stage, since the panel track is temporary.

Once the panel track is laid, a work train (pulled by diesel

locomotives) can bring in the sections of continuous welded rail that will be used for

the permanent way of this first track. The rail comes from the factory in lengths

varying from 200 m (660 ft) to 400 m (1310 ft). Such long pieces of rail are just laid

across several flatcars; they are very flexible, so this does not pose a problem. A

special crane unloads the rail sections and places them on each side of the

temporary track, approximately 3.5 m (12 ft) apart. This operation is usually carried

out at night, for thermal reasons. The rail itself is standard UIC section, 60 kg/m

(40 lb/ft), with a tensile strength of 800 newtons per square millimetre or

megapascals (116,000 psi).

For the next step, a gantry crane is used again. This time,

however, the crane rides on the two rails that were just laid alongside the temporary

track. A train of flatcars, half loaded with LGV sleepers, arrives at the site. It is

pushed by a special diesel locomotive, which is low enough to fit underneath the

gantry cranes. The cranes remove the panels of temporary track, and stack them

onto the empty half of the sleeper train. Next, they pick up sets of 30 LGV sleepers,

pre-arranged with the proper spacing (60 cm, or 24 in), using a special fixture. The

sleepers are laid on the gravel bed where the panel track was. The sleeper train

leaves the worksite loaded with sections of panel track.

The sleepers, sometimes known as bi-bloc sleepers, are U41

twin block reinforced concrete, 2.4 m (7 ft 10 in.) wide, and weigh 245 kg (540 lb)

each. They are equipped with hardware for Nabla RNTC spring fasteners, and a

9 mm (3/8 in.) rubber pad. (Rubber pads are always used under the rail on concrete

sleepers, to avoid cracking). Next, a rail threader is used to lift the rails onto their

final position on the sleepers. This machine rides on the rails just like the gantry

cranes, but can also support itself directly on a sleeper. By doing this, it can lift the

rails, and shift them inwards over the ends of the sleepers, to the proper gauge

(standard gauge). It then lowers them onto the rubber sleeper cushions, and workers

26D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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use a pneumatically operated machine to bolt down the Nabla clips with a

predetermined torque. The rails are canted inward at a slope of 1 in 20.

4.4.4 Joining track sections

The sections of rail are welded together using thermite.

Conventional welding (using some type of flame) does not work well on large metal

pieces such as rails, since the heat is conducted away too quickly. Thermite is better

suited to this job. It is a mix of aluminium powder and rust (iron oxide) powder,

which reacts to produce iron, aluminum oxide, and a great deal of heat, making it

ideal to weld rail.

Before the rail is joined, its length must be adjusted very

accurately. This ensures that the thermal stresses in the rail after it is joined into one

continuous piece do not exceed certain limits, resulting in lateral kinks (in hot

weather) or fractures (in cold weather). The joining operation is performed by an

aluminothermic welding machine which is equipped with a rail saw, a weld shear and

a grinder. When the thermite welding process is complete, the weld is ground to the

profile of the rail, resulting in a seamless join between rail sections. Stress in the rail

due to temperature variations is absorbed without longitudinal strain, except near

bridges where an expansion joint is sometimes used.

4.4.5 Adding ballast

The next step consists of stuffing a deep bed of ballast

underneath the new track. The ballast arrives in a train of hopper cars pulled by

diesel locomotives. Handling this train is challenging, since the ballast must be

spread evenly. If the train stops, ballast can pile over the rails and derail it.

A first layer of ballast is dumped directly onto the track, and a

tamping-lining-levelling machine, riding on the rails, forces the stones underneath

the sleepers. Each pass of this machine can raise the level of the track by 8 cm (3 in),

so several passes of ballasting and of the machine are needed to build up a layer of

ballast at least 32 cm (1 ft) thick under the sleepers. The ballast is also piled on each

side of the track for lateral stability. The machine performs the initial alignment of

27D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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the track. Next, a ballast regulator distributes the ballast evenly. Finally, a dynamic

vibrator machine shakes the track to perform the final tamping, effectively

simulating the passing of 2500 axles.

4.4.6 Finishing construction

Now that the first track is almost complete, work begins on

the adjacent track. This time, however, it is not necessary to lay a temporary track.

Trains running on the first track bring the sleepers, and then the rail, which is

unloaded directly onto the sleepers by dispensing arms that swing out to the proper

alignment. The Nabla fasteners are secured, and the ballast is stuffed under the

track as before.

The two tracks are now essentially complete, but the work on

the line is not finished. The catenary masts need to be erected, and the wire strung

on them. Catenary installation is not complicated; it will suffice to give a brief

summary of specifications. The steel masts are I-beams, placed in a concrete

foundation up to 63 m (206 ft) apart. The supports are mounted on glass insulators.

The carrier wire is bronze, 65 mm² cross section, 14 kN (3100 lbf) tension. The stitch

wire is bronze, 15 m (49.21 ft) long, 35 mm² cross-section. The droppers are 5 mm

stranded copper cable. The contact wire is hard drawn copper, 120 mm², flat section

on the contact side, 14 kN tension. The maximum depth of the catenary (distance

between carrier and contact wires) is 1.4 m (4.59 ft). The contact wire can rise a

maximum of 240 mm (9.44 inches) but the normal vertical displacement does not

exceed 120 mm (4.72 inches).

Now that the catenary is complete, the track is given final alignment adjustments

down to millimeter tolerances. The ballast is then blown to remove smaller gravel

fragments and dust, which might be kicked up by trains. This step is especially

important on high-speed tracks, since the blast of a passing train is strong. Finally,

TGV trains are tested on the line at gradually increasing speeds. The track is

qualified at speeds slightly higher than will be used in everyday operations (typically

350 km/h, or 210 mph), before being opened to commercial service.

28D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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4.5 Stations and lines

The London Underground's 11 lines are divided into two classes: the subsurface

routes and the deep-tube routes. The Circle, District, Hammersmith & City, and

Metropolitan lines make up the subsurface class. The Bakerloo, Central, Jubilee,

Northern, Piccadilly, Victoria and Waterloo & City lines make up the deep-tube

routes.

There was a twelfth line, a fifth subsurface route, the East London line, until 2007,

when it closed for rebuilding work. It reopened as part of London Overground in

April 2010.[38]

The Underground serves 270 stations by rail. Fourteen

Underground stations are outside Greater London, of which five (Amersham,

Chalfont & Latimer, Chesham, and Chorleywood on the Metropolitan Line, and

Epping on the Central Line) are beyond the M25 London Orbital motorway. Of the 32

London boroughs, six (Bexley, Bromley, Croydon, Kingston, Lewisham and Sutton)

are not served by the Underground network, while Hackney has Old Street and

Manor House only just inside its boundaries.

FIG: 4.1

29D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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Zone 1 (central zone) of the Underground (and DLR) network in a

geographically more accurate layout than the usual Tube map, using the same style.

FIG: 4.2

Underground trains come in two sizes, larger subsurface trains

and smaller tube trains. A Metropolitan line A Stock train (left) passes a Piccadilly

line 1973 Stock train (right) in the siding at Rayners Lane

Lines on the Underground can be classified into two types:

subsurface and deep-level. The subsurface lines were dug by the cut-and-cover

method, with the tracks running about 5 m (16 ft 5 in) below the surface. The deep-

level or tube lines, bored using a tunnelling shield, run about 20 m (65 ft 7 in) below

the surface (although this varies considerably), with each track in a separate tunnel.

These tunnels can have a diameter as small as 3.56 m (11 ft 8 in), and the loading

gauge is thus considerably smaller than on the subsurface lines. Lines of both types

usually emerge on to the surface outside the central area.

While the tube lines are for the most part self-contained with a

few exceptions, the subsurface lines are part of an interconnected network: each

shares track with at least two other lines. The subsurface arrangement is similar to

the New York City Subway, which also runs separate "lines" over shared tracks.

30D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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`

4.6 Rolling stock and electrification

London Underground rolling stock

FIG: 4.3

1996 Stock trains at Stratford Market Depot

The Underground uses rolling stock built between 1960 and the

present. Stock on subsurface lines is identified by a letter (such as A Stock, used on

the Metropolitan line), while tube stock is identified by the year in which it was

designed (for example, 1996 Stock, used on the Jubilee line). All lines are worked by

a single type of stock except the District line, which uses both C and D Stock. Two

types of stock are currently being developed — 2009 Stock for the Victoria line and S

stock for the subsurface lines, with the Metropolitan line A Stock due to be replaced

first. Rollout of both began in 2009. In addition to the electric multiple units

described above, there is engineering stock, such as ballast trains and brake vans,

identified by a 1–3 letter prefix then a number.

The Underground is one of the few networks in the world that

uses a four-rail system. The additional rail carries the electrical return that on third-

rail and overhead networks is provided by the running rails. The reason for this is

that the return current, if allowed to flow through the running rails, would also tend

to flow through the cast-iron tunnel segments. These were never designed to carry

31D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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electrical currents and would suffer from galvanic corrosion if significant currents

were allowed to flow through the joints. On the Underground, a top-contact third rail

is beside the track, energised at +420 V DC and a top-contact fourth rail is centrally

between the running rails, at −210 V DC, which combine to provide a traction

voltage of 630 V DC.

In cases where the lines are shared with mainline trains which use a three-rail

system (usually above ground and not within cast iron tunnel segments), the third

rail is set at +630 V and the fourth rail at 0 V DC.[40]

4.7 Planned improvements and expansions

The Crossrail line will provide a new east-west link and will be

integrated with the tube network, but will not be part of it.

Each line is being upgraded to improve capacity and reliability,

with new computerised signalling, automatic train operation (ATO), track

replacement, station refurbishment and, where needed, new rolling stock. A trial of

mobile phone coverage on the Waterloo & City line determined that coverage would

be appropriate for the entire network, with aims to have the service installed in time

for the 2012 Olympics. Mayor of London Boris Johnson revealed the plans would be

funded through investment from the five main UK mobile networks; Vodafone,

Orange, T-Mobile, 3 and O2.

In summer, temperatures on parts of the Underground can

become very uncomfortable due to its deep and poorly ventilated tube tunnels;

temperatures as high as 47 °C (117 °F) were reported in the 2006 European heat

wave. A trial programme for a groundwater cooling system in Victoria station took

place in 2006 and 2007; it aimed to determine whether such a system would be

feasible and effective if in widespread use for cooling the Underground. Posters may

be observed on the Underground network advising passengers to carry a bottle of

water to help keep cool. The new S Stock trains will have air conditioning.

32D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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Although not part of London Underground, the Crossrail scheme

will provide a new route across central London by 2018, integrated with the tube

network but not part of it. The long proposed Chelsea-Hackney Line, which would

not be built until after Crossrail, may become part of the London Underground. It

would give the network a new Northeast to South cross-London line to provide more

interchanges with other lines and relieve overcrowding on other lines. However, it is

still on the drawing-board and may be either part of the London Underground

network or the National Rail network. The Croxley Rail Link proposal envisages

diverting the Metropolitan line Watford branch to Watford Junction station along a

disused railway track. The project awaits funding from the Department for Transport

and remains at the proposal stage.

Boris Johnson has suggested extending the Bakerloo Line to

Lewisham, Catford and Hayes as South London lacks Underground lines (instead

having a suburban rail network).

Proposals have also been made to reorganise the sub-surface

lines and split the Northern line and extend the Charing Cross branch to Battersea,

although both of these are dependent upon other upgrades being completed first.

The plan to extend the Northern line to Battersea has been given planning

permission by the London Borough of Wandsworth and could be open by 2015. In

early 2011 the London Mayor also suggested extended the Northern Line to better

accommodate workers in Greater London. Mr Johnson said that following recent

office developments in Vauxhall and Battersea, the council are now thinking about

extending the Northern Line west from Kennington - such an extension would create

two new stops along the Northern Line.

4.8 History

History of the London Underground

Railway construction in the United Kingdom began in the early 19th century. By

1854 six railway terminals had been built just outside the centre of London: London

Bridge, Euston, Paddington, London King's Cross, Bishopsgate and Waterloo. At this

point, only Fenchurch Street station was located in the actual City of London. Traffic

33D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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congestion in the city and the surrounding areas had increased significantly in this

period, partly due to the need for rail travellers to complete their journeys into the

city centre by road. The idea of building an underground railway to link the City of

London with the mainline terminals had first been proposed in the 1830s, but it was

not until the 1850s that the idea was taken seriously as a solution to traffic

congestion.

The first underground railways

FIG: 4.4

Construction of the Metropolitan Railway near King's Cross

station, 1861

In 1855 an Act of Parliament was passed approving the

construction of an underground railway between Paddington Station and Farringdon

Street via King's Cross which was to be called the Metropolitan Railway. The Great

Western Railway (GWR) gave financial backing to the project when it was agreed

that a junction would be built linking the underground railway with their mainline

terminus at Paddington. GWR also agreed to design special trains for the new

subterranean railway.

A shortage of funds delayed construction for several years. The

fact that this project got under way at all was largely due to the lobbying of Charles

Pearson, who was Solicitor to the City of London Corporation at the time. Pearson

had supported the idea of an underground railway in London for several years. He

advocated plans for the demolition of the unhygienic slums which would be replaced

by new accommodation for their inhabitants in the suburbs, with the new railway

34D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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providing transportation to their places of work in the city centre. Although he was

never directly involved in the running of the Metropolitan Railway, he is widely

credited as being one of the first true visionaries behind the concept of underground

railways. And in 1859 it was Pearson who persuaded the City of London Corporation

to help fund the scheme. Work finally began in February 1860, under the guidance of

chief engineer John Fowler. Pearson died before the work was completed.

The Metropolitan Railway opened on 10 January 1863. Within a

few months of opening it was carrying over 26,001 passengers a day. The

Hammersmith and City Railway was opened on 13 June 1864 between Hammersmith

and Paddington. Services were initially operated by GWR between Hammersmith and

Farringdon Street. By April 1865 the Metropolitan had taken over the service. On 23

December 1865 the Metropolitan's eastern extension to Moorgate Street opened.

Later in the decade other branches were opened to Swiss Cottage, South Kensington

and Addison Road, Kensington (now known as Kensington Olympia). The railway had

initially been dual gauge, allowing for the use of GWR's signature broad gauge

rolling stock and the more widely used standard gauge stock. Disagreements with

GWR had forced the Metropolitan to switch to standard gauge in 1863 after GWR

withdrew all its stock from the railway. These differences were later patched up,

however broad gauge was totally withdrawn from the railway in March 1869.

On 24 December 1868, the Metropolitan District Railway

began operating services between South Kensington and Westminster using

Metropolitan Railway trains and carriages. The company, which soon became known

as "the District", was first incorporated in 1864 to complete an Inner Circle railway

around London in conjunction with the Metropolitan. This was part of a plan to build

both an Inner Circle line and Outer Circle line around London.

A fierce rivalry soon developed between the District and the

Metropolitan. This severely delayed the completion of the Inner Circle project as the

two companies competed to build far more financially lucrative railways in the

suburbs of London. The London and North Western Railway (LNWR) began running

their Outer Circle service from Broad Street via Willesden Junction, Addison Road

and Earl's Court to Mansion House in 1872. The Inner Circle was not completed until

35D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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1884, with the Metropolitan and the District jointly running services. In the

meantime, the District had finished its route between West Brompton and Blackfriars

in 1870, with an interchange with the Metropolitan at South Kensington. In 1877, it

began running its own services from Hammersmith to Richmond, on a line originally

opened by the London & South Western Railway (LSWR) in 1869. The District then

opened a new line from Turnham Green to Ealing in 1879 and extended its West

Brompton branch to Fulham in 1880. Over the same decade the Metropolitan was

extended to Harrow-on-the-Hill station in the north-west.

The early tunnels were dug mainly using cut-and-cover

construction methods. This caused widespread disruption and required the

demolition of several properties on the surface. The first trains were steam-hauled,

which required effective ventilation to the surface. Ventilation shafts at various

points on the route allowed the engines to expel steam and bring fresh air into the

tunnels. One such vent is at Leinster Gardens, W2. In order to preserve the visual

characteristics in what is still a well-to-do street, a five-foot-thick (1.5 m) concrete

façade was constructed to resemble a genuine house frontage.

On 7 December 1869 the London, Brighton and South Coast

Railway (LB&SCR) started operating a service between Wapping and New Cross

Gate on the East London Railway (ELR) using the Thames Tunnel designed by Marc

Brunel, who designed the revolutionary tunnelling shield method which made its

construction not only possible, but safer, and completed by his son Isambard

Kingdom Brunel. This had opened in 1843 as a pedestrian tunnel, but in 1865 it was

purchased by the ELR (a consortium of six railway companies: the Great Eastern

Railway (GER); London, Brighton and South Coast Railway (LB&SCR); London,

Chatham and Dover Railway (LCDR); South Eastern Railway (SER); Metropolitan

Railway; and the Metropolitan District Railway) and converted into a railway tunnel.

In 1884 the District and the Metropolitan began to operate services on the line.

By the end of the 1880s, underground railways reached

Chesham on the Metropolitan, Hounslow, Wimbledon and Whitechapel on the

District and New Cross on the East London Railway. By the end of the 19th century,

the Metropolitan had extended its lines far outside of London to Aylesbury, Verney

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Junction and Brill, creating new suburbs along the route, later publicised by the

company as Metro-land. Right up until the 1930s the company maintained ambitions

to be considered as a main line rather than an urban railway, ambitions that are still

continued somewhat today.

4.9 First tube lines

FIG: 4.5

The nickname "the Tube" comes from the circular tube-like tunnels through which

the trains travel. Northern Line train leaving a tunnel mouth just north of Hendon

Central station.

Following advances in the use of tunnelling shields, electric

traction and deep-level tunnel designs, later railways were built even further

underground. This caused much less disruption at ground level and it was therefore

cheaper and preferable to the cut-and-cover construction method.

The City & South London Railway (C&SLR, now part of the

Northern Line) opened in 1890, between Stockwell and the now closed original

terminus at King William Street. It was the first "deep-level" electrically operated

railway in the world. By 1900 it had been extended at both ends, to Clapham

Common in the south and Moorgate Street (via a diversion) in the north. The second

such railway, the Waterloo and City Railway (W&CR), opened in 1898. It was built

and run by the London and South Western Railway.

37D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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On 30 July 1900, the Central London Railway (now known as

the Central Line) was opened, operating services from Bank to Shepherd's Bush. It

was nicknamed the "Twopenny Tube" for its flat fare and cylindrical tunnels; the

"tube" nickname was eventually transferred to the Underground system as a whole.

An interchange with the C&SLR and the W&CR was provided at Bank. Construction

had also begun in August 1898 on the Baker Street & Waterloo Railway, however

work came to a halt after 18 months when funds ran out.

4.10 Integration

In the early 20th century the presence of six independent

operators running different Underground lines caused passengers substantial

inconvenience; in many places passengers had to walk some distance above ground

to change between lines. The costs associated with running such a system were also

heavy, and as a result many companies looked to financiers who could give them the

money they needed to expand into the lucrative suburbs as well as electrify the

earlier steam operated lines. The most prominent of these was Charles Yerkes, an

American tycoon who secured the right to build the Charing Cross, Euston and

Hampstead Railway (CCE&HR) on 1 October 1900, today also part of the Northern

Line. In March 1901, he effectively took control of the District and this enabled him

to form the Metropolitan District Electric Traction Company (MDET) on 15 July.

Through this he acquired the Great Northern and Strand Railway and the Brompton

and Piccadilly Circus Railway in September 1901, the construction of which had

already been authorised by Parliament, together with the moribund Baker Street &

Waterloo Railway in March 1902. The GN&SR and the B&PCR evolved into the

present-day Piccadilly Line. On 9 April the MDET evolved into the Underground

Electric Railways Company of London (UERL). The UERL also owned three tramway

companies and went on to buy the London General Omnibus Company, creating an

organisation colloquially known as "the Combine" which went on to dominate

underground railway construction in London until the 1930s.

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FIG: 4.6

The Circle Line and District Line platforms at Embankment

station

With the financial backing of Yerkes, the District opened its

South Harrow branch in 1903 and completed its link to the Metropolitan's Uxbridge

branch at Rayners Lane in 1904—although services to Uxbridge on the District did

not begin until 1910 due to yet another disagreement with the Metropolitan. Today,

District Line services to Uxbridge have been replaced by the Piccadilly Line. By the

end of 1905, all District Railway and Inner Circle services were run by electric trains.

The Baker Street & Waterloo Railway opened in 1906, soon

branding itself the Bakerloo and, by 1907, it had been extended to Edgware Road in

the north and Elephant & Castle in the south. The newly named Great Northern,

Piccadilly and Brompton Railway, combining the two projects acquired by MDET in

September 1901, also opened in 1906. With tunnels at an impressive depth of

200 feet (61 m) below the surface, it ran from Finsbury Park to Hammersmith; a

single station branch to Strand (later renamed Aldwych) was added in 1907. In the

same year the CCE&HR opened from Charing Cross to Camden Town, with two

northward branches, one to Golders Green and one to Highgate (now Archway).

Independent ventures did continue in the early part of the

20th century. The independent Great Northern & City Railway opened in 1904

between Finsbury Park and Moorgate. It was the only tube line of sufficient diameter

to be capable of handling main line stock, and it was originally intended to be part of

a main line railway. However money soon ran out and the route remained separate

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from the main line network until the 1970s. The C&SLR was also extended

northwards to Euston by 1907.

In early 1908, in an effort to increase passenger numbers, the

underground railway operators agreed to promote their services jointly as "the

Underground", publishing new adverts and creating a free publicity map of the

network for the purpose. The map featured a key labelling the Bakerloo Railway, the

Central London Railway, the City & South London Railway, the District Railway, the

Great Northern & City Railway, the Hampstead Railway (the shortened name of the

CCE&HR), the Metropolitan Railway and the Piccadilly Railway. Other railways

appeared on the map but with much less prominence; these included the Waterloo &

City Railway and part of the ELR, which were both owned by main line railway

companies at the time. As part of the process, "The Underground" name appeared on

stations for the first time and electric ticket-issuing machines were also introduced.

This was followed in 1913 by the first appearance of the famous circle and horizontal

bar symbol, known as "the roundel", designed by Edward Johnston. In January 1933

the UERL experimented with a new diagrammatic map of the Underground,

designed by Harry Beck and first issued in pocket-size form. It was an immediate

success with the public and is now commonly regarded as a design classic; an

updated version is still in use today.

Meanwhile, on 1 January 1913 the UERL absorbed two other

independent tube lines, the C&SLR and the Central London Railway. As the Combine

expanded, only the Metropolitan stayed away from this process of integration,

retaining its ambition to be considered as a main line railway. Proposals were put

forward for a merger between the two companies in 1913 but the plan was rejected

by the Metropolitan. In the same year the company asserted its independence by

buying out the cash strapped Great Northern and City Railway, a predecessor to the

Piccadilly Line. It also sought a character of its own. The Metropolitan Surplus Lands

Committee had been formed in 1887 to develop accommodation alongside the

railway and in 1919 Metropolitan Railway Country Estates Ltd. was founded to

capitalise on the post-World War One demand for housing. This ensured that the

Metropolitan would retain an independent image until the creation of London

Transport in 1933.

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The Metropolitan also sought to electrify its lines. The District

and the Metropolitan had agreed to use the low voltage DC system for the Inner

Circle, comprising two electric rails to power the trains, back in 1901. At the start of

1905 electric trains began to work the Uxbridge branch and from 1 November 1906

electric locomotives took trains as far as Wembley Park where steam trains took

over. This changeover point was moved to Harrow-on-the-Hill on 19 July 1908. The

Hammersmith & City branch had also been upgraded to electric working on 5

November 1906. The electrification of the ELR followed on 31 March 1913, the same

year as the opening of its extension to Whitechapel and Shoreditch. Following the

Grouping Act of 1921, which merged all the cash strapped main line railways into

four companies (thus obliterating the original consortium that had built the ELR), the

Metropolitan agreed to run passenger services on the line.

The Bakerloo Line extension to Queen's Park was completed in

1915, and the service extended to Watford Junction via the London and North

Western Railway tracks in 1917. The extension of the Central Line's branch to Ealing

Broadway was delayed by the war until 1920.

The major development of the 1920s was the integration of the

CCE&HR and the C&SLR and extensions to form what was to become the Northern

line. This necessitated enlargement of the older parts of the C&SLR, which had been

built on a modest scale. The integration required temporary closures during 1922—

24. The Golders Green branch was extended to Edgware in 1924, and the southern

end was extended from Clapham Common to Morden in 1926 with new stations

designed by Charles Holden.[21] Through Holden's work as consulting architect,

designing new stations during the 1920s and 1930s, London Underground was

modernised and every aspect of design carefully integrated.

The Watford branch of the Metropolitan opened in 1925 and in

the same year electrification was extended to Rickmansworth. The last major work

completed by the Metropolitan was the branch to Stanmore which opened in 1932

and which is now part of the Jubilee Line.

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By 1933 the Combine had completed the Cockfosters branch

of the Piccadilly Line, with through services running (via realigned tracks between

Hammersmith and Acton Town) to Hounslow West and Uxbridge. The extension of

the Piccadilly line was heavily promoted by London Underground.

CASE STUDY

London Transport

In 1933 the Combine, the Metropolitan and all the municipal

and independent bus and tram undertakings were merged into the London Passenger

Transport Board (LPTB), a self-supporting and unsubsidised public corporation which

came into being on 1 July 1933. The LPTB soon became known as London Transport

(LT).

Shortly after it was created, LT began the process of

integrating the underground railways of London into one network. All the separate

railways were renamed as "lines" within the system: the first LT version of Beck's

map featured the District Line, the Bakerloo Line, the Piccadilly Line, the Edgware,

Highgate and Morden Line, the Metropolitan Line, the Metropolitan Line (Great

Northern & City Section), the East London Line, and the Central London Line. The

shorter names Central Line and Northern Line were adopted for two lines in 1937.

The Waterloo & City line was not originally included in this map as it was still owned

by a main line railway and not part of LT, but was added in a less prominent style,

also in 1937.

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FIG: 4.7

Londoners sheltering from The Blitz in a tube station

LT announced a scheme for the expansion and modernisation of

the network entitled the New Works Programme, which had followed the

announcement of improvement proposals for the Metropolitan Line. This consisted of

plans to extend some lines, to take over the operation of others from main-line

railway companies, and to electrify the entire network. During the 1930s and 1940s,

several sections of main-line railways were converted into surface lines of the

Underground system. The oldest part of today's Underground network is the Central

line between Leyton and Loughton, which opened as a railway seven years before the

Underground itself.

LT also sought to abandon routes which made a significant

financial loss. Soon after the LPTB started operating, services to Verney Junction and

Brill on the Metropolitan Railway were stopped. The renamed Metropolitan Line

terminus was moved to Aylesbury.

The outbreak of World War II delayed all the expansion schemes.

From mid-1940, the Blitz led to the use of many Underground stations as shelters

during air raids and overnight. The Underground helped over 200,000 children

escape to the countryside and sheltered another 177,500 people. The authorities

initially tried to discourage and prevent people from sleeping in the tube, but later

supplied 22,000 bunks, latrines, and catering facilities. After a time there were even

special stations with libraries and classrooms for night classes. Later in the war,

eight London deep-level shelters were constructed under stations, ostensibly to be

43D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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used as shelters (each deep-level shelter could hold 8,000 people) though plans were

in place to convert them for a new express line parallel to the Northern line after the

war. Some stations (now mostly disused) were converted into government offices: for

example, Down Street was used for the headquarters of the Railway Executive

Committee and was also used for meetings of the War Cabinet before the Cabinet

War Rooms were completed; Brompton Road was used as a control room for anti-

aircraft guns and the remains of the surface building are still used by London's

University Royal Naval Unit (URNU) and University London Air Squadron (ULAS).

After the war one of the last acts of the LPTB was to give the go-

ahead for the completion of the postponed Central Line extensions. The western

extension to West Ruislip was completed in 1948, and the eastern extension to

Epping in 1949; the single-line branch from Epping to Ongar was taken over and

electrified in 1957.

GLC Control

On 1 January 1970, the Greater London Council (GLC) took over

responsibility for London Transport, again under the formal title London Transport

Executive. This period is perhaps the most controversial in London's transport

history, characterised by staff shortages and a severe lack of funding from central

government. In 1980 the Labour-led GLC began the 'Fares Fair' project, which

increased local taxation in order to lower ticket prices. The campaign was initially

successful and usage of the Tube significantly increased. But serious objections to

the policy came from the London Borough of Bromley, an area of London which has

no Underground stations. The Council resented the subsidy as it would be of little

benefit to its residents. The council took the GLC to the Law Lords who ruled that

the policy was illegal based on their interpretation of the Transport (London) Act

1969. They ruled that the Act stipulated that London Transport must plan, as far as

was possible, to break even. In line with this judgement, 'Fares Fair' was therefore

reversed, leading to a 100% increase in fares in 1982 and a subsequent decline in

passenger numbers. The scandal prompted Margaret Thatcher's Conservative

Government to remove London Transport from the GLC's control in 1984, a

development that turned out to be a prelude to the abolition of the GLC in 1986.

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However the period saw the first real postwar investment in the

network with the opening of the carefully planned Victoria line, which was built on a

diagonal northeast-southwest alignment beneath central London, incorporating

centralised signalling control and automatically driven trains. It opened in stages

between 1968 and 1971. The Piccadilly line was extended to Heathrow Airport in

1977, and the Jubilee Line was opened in 1979, taking over the Stanmore branch of

the Bakerloo line, with new tunnels between Baker Street and Charing Cross. There

was also one important legacy from the 'Fares Fair' scheme: the introduction of

ticket zones, which remain in use today.

London Regional Transport

In 1984 Margaret Thatcher's Conservative Government removed

London Transport from the GLC's control, replacing it with London Regional

Transport (LRT) on 19 June 1984 – a statutory corporation for which the Secretary of

State for Transport was directly responsible. The Government planned to modernise

the system while slashing its subsidy from taxpayers and ratepayers. As part of this

strategy London Underground Limited was set up on 1 April 1985 as a wholly owned

subsidiary of LRT to run the network.

The prognosis for LRT was good. Oliver Green, the then Curator

of the London Transport Museum, wrote in 1987:

In its first annual report, London Underground Ltd was able to

announce that more passengers had used the system than ever before. In 1985–86

the Underground carried 762 million passengers – well above its previous record

total of 720 million in 1948. At the same time costs have been significantly reduced

with a new system of train overhaul and the introduction of more driver-only

operation. Work is well in hand on the conversion of station booking offices to take

the new Underground Ticketing System (UTS)...and prototype trials for the next

generation of tube trains (1990) stock started in late 1986. As the London

Underground celebrates its 125th anniversary in 1988, the future looks promising.

However, cost-cutting did not come without critics. At 19:30 on

18 November 1987, a massive fire swept through the King's Cross St Pancras tube

45D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING

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station, the busiest station on the network, killing 31 people. It later turned out that

the fire had started in an escalator shaft to the Piccadilly Line, which was burnt out

along with the top level (entrances and ticket hall) of the deep-level tube station. The

escalator on which the fire started had been built just before World War II. The steps

and sides of the escalator were partly made of wood, meaning that they burned

quickly and easily. Although smoking was banned on the subsurface sections of the

London Underground in February 1985 as a consequence of the Oxford Circus fire,

the fire was most probably caused by a commuter discarding a burning match, which

fell down the side of the escalator onto the running track (Fennell 1988, p. 111). The

running track had not been cleaned in some time and was covered in grease and

fibrous detritus. The Member of Parliament for the area, Frank Dobson, informed the

House of Commons that the number of transportation employees at the station,

which handled 200,000 passengers every day at the time, had been cut from 16 to

ten, and the cleaning staff from 14 to two. The tragic event led to the abolition of all

wooden escalators at all Underground stations and pledges of greater investment.

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Conclusion

References

47D.Y.P.C.O.E, AKURDI.PUNE DEPARTMENT OF CIVIL ENGINEERING