railway coursework

8/11/2019 Railway Coursework

1/8


2/8

Section 169/880-169/1320

This section has carried out 8 tamping in 4 years. Obviously tamping does not reduce the

standard deviation significantly; in fact it may leave the ballast in a loosened state. For that

reason, immediate settlement is expected as shown in figure below.

Figure below show the ground penetrating radar for section 169/880-170. The ballastinterface at apparent depth of 0.7m is generally weak and relatively poor defined. The weak

image could have been caused by a poor contrast at the interface or by dirt accumulation in

the ballast.

0

0.5

1

1.5

2

2.5

3

3.5

01/0

/0

11/03/0

16/11/06

1

/10/06

20/08/06

25/06/06

28/05/06

30/0

/06

28/02/06

2

/01/06

29/12/05

08/09/05

12/08/05

03/06/05

29/0

/05

1

/10/0

09/09/0

30/0

/0

02/0

/0

05/03/0

10/01/0

StandardDeviationmm

169/880-169/1100 169/1100-169/1320


3/8

Figure below show the Automatic Ballast Sampling at a few points along the railway on

section 169 miles. Clean ballast is observed at depth of 0.4m however at about 0.5m depth

consists of dirty ballast.

Section 169/1320-170/880

This section is generally being tamped 3 times over 4 years. This section is in good conditionfor the entire period. Therefore no maintenance work is required.

Section 170/880-170/1100

Deteriorate rate of standard deviation increased because this section has no maintenance

since 2006. This may lead to track unevenness and affect the riding quality.

Section 170/1100-173/1320

This section is generally being tamped once per year. This section is in good condition for

the entire period. Therefore no maintenance work is required.

Section 173/1320-174/660

This section has carried out 3 tamping and 5 S&C tamping in 4 years time. From the historic

data, this section has the highest standard deviation on the entire track. The reason for that

is due to its heavy traffic and it serves as switches and crossings on this section. At the

switches and crossings, the train has to slow down therefore the subgrade beneath it may

subject to a large stress. The maintenance work did not improved the quality of the track, in

fact, it deteriorate the condition of the track rapidly.

0

0.2

0.4

0.6

0.8

1

1.2

500 600 700 800 900 1000 1100 1200 1300 1400 1500

Depth,

m

169 miles

Well compacted weak rock Very Dirty Ballast Dirty Ballast

Clean Ballast Very Clean Ballast


4/8

From the GPR diagram as shown below, it clearly show the extremely weak ballast or

formation interface at the highlighted area. The weak ballast interface can be further

confirmed through the ABS data, as shown below.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

173.2 173.4 173.6 173.8 174 174.2 174.4 174.6

Depth,

m

173 -174 miles

Series1 Clean Ballast Dirty Ballast Well Compacted Weak Rock


5/8

Section 174/660-182/1320

Under appropriate maintenance, this section has a lower standard deviation comparing with

data from 10/1/2004. Traffic volume is much lower in this section and the initial quality of

track is good, therefore under normal tamping the rate of deteriorate is kept to the

minimum.

Section 182/1320-182/1540

This section has the same problem with section 173/1320 to 174/660, as these two sections

are switches and crossings. However, this section has less traffic load compares to the

sections mentioned above. This section has carried out 4 tamp in 4 years and an S&C tamp.

However, from the figure below it can be seen that the standard deviation did not increase

the quality of the track much.

Summary of Ballast Sample Information

Figure below shows the summary of the ABS test which carried in certain point for the

whole 13miles of the track. The ballast for the overall section is well maintained as clean

ballast appeared until depth of 0.4m. However the ballast for section 169-172miles, dirty

ballast is observed at 0.5m, therefore suitable survey and maintenance should carry out to

decrease the rate of deteriorate of rail.

2

2.2

2.4

2.6

2.8

3

3.2

3.4

3.6

01/0

/0

11/03/0

30/01/0

16/11/06

1

/10/06

2

/01/06

29/12/05

30/11/05

0

/10/05

1

/10/0

09/09/0

Standar

dDeviation,

mm

182/1320-182/1540


6/8

0

0.2

0.4

0.6

0.8

1

1.2

Depth

(m)

Distance (169miles to 183 miles)

Very Clean Ballast Clean Ballast Slightly Dirty Ballast

Dirty Ballast Very Dirty Ballast(non cohesive) Very Dirty Ballast (cohesive)

Dirty Ballast

172 miles


7/8

Plot of FWD data (Section 173-174)

The two figures below show the FWD data from Section 173/1100 to 174/205. For section

173, it can be seen that the deflection are less consistence which mean the subgrade for the

whole section might not have the same subgrade strength. However in Section 174, the

deflection is more consistence as from the red line show in figure 2, this section has the

same subgrade strength.

Figure 1

Figure 2

0

200

400

600

800

1000

1200

1000 1100 1200 1300 1400 1500 1600 1700 1800

Deflection(microns)

yards

Section 173

d0 d300 d1000 d2000

0

200

400

600

800

1000

1200

0 50 100 150 200

eflections(microns)

Yards

Section 174

d0 d300 d1000 d2000


8/8

Recommendations Summary

For section 169/880-169/1320

Ballast cleaning or ballast replacing would be the appropriate method to clean the dirt

accumulated. Ballast replacing is much more expensive compare with ballast cleaning. Boththese methods cannot improve the variation in subgrade and the track will still remember

where to settle. It can only be solve on fully reconstruction, however it is not recommended

due to it high cost.

For section 170/880-170/1100

Tamping would be the appropriate method to decrease the deteriorate rate.

ForSection 173/1320-174/660 and 182/1320-182/1540

Ballast Cleaning would be appropriate method to improve the condition of the ballast, and

therefore reduce the standard deviation.

Besides the ballast and subgrade inspection, investigation on rail head corrugation head has

to be carried out frequently. Because the steel of the rails is continually deforming, it is

necessary to grind the top and side surfaces of the rail head smooth. Drainage survey should

be conducted on the dirty ballast to observe the drainage condition.

Conclusion

The entire section of track is well maintained, further maintenance are only focuses to a

small section listed on the recommendations summary. Railway has to be maintain well in

order to have a high quality of ride, reduce the deteriorate rate of ballast, reduce the

accident occurs, and minimize the cost of maintenance in the future.

railway coursework

Documents