Railway Engineering: Cant on Curved Tracks

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Questions and Answers

What is the purpose of marking the gauge face of the outer rail at a distance of at least 30 m behind the beginning of the curve?

To determine the revised alignment of the curve
To ensure inclusion of the point of commencement of the curve (correct)
To measure the versine readings along the gauge face of the outer rail
To compute the slews including provision of correct super-elevation

At what interval should the stations be marked on the rail if station markings are not available at every 10 m interval?

Every 10 m interval (correct)
Every 5 m interval
Every 20 m interval
Every 30 m interval

What is the accuracy level at which the versines are measured?

5 mm
0.5 mm
1 mm (correct)
0.1 mm

What is the purpose of the fishing cord or wire in the versine survey?

To stretch out over the full length of the curve (C) Signup and view all the answers

Where should the mark be made on the gauge face of the outer rail at the beginning of the curve?

At a distance of at least 30 m behind the beginning of the curve (C) Signup and view all the answers

What is the purpose of operation No. 1 in string lining operations?

Versine survey of the curve (C) Signup and view all the answers

What is the criteria for realignment of a curve based on service limit for station to station versine variation?

As per Para 524 (A) Signup and view all the answers

How should the 'stations' be marked on the rail?

In white paint (A) Signup and view all the answers

What is the unit of cant, as per the given content?

mm (A) Signup and view all the answers

What is the maximum cant allowed on Broad Gauge Group 'A', 'B', and 'C' routes?

165 mm (C) Signup and view all the answers

For what purpose is a maximum cant of 185 mm assumed on Group 'A' routes?

All of the above (D) Signup and view all the answers

Who needs to approve changes to the super-elevation of a line?

Chief Engineer (D) Signup and view all the answers

What is the maximum value of cant deficiency allowed on routes with sectional speed more than 100 Kmph?

100 mm (D) Signup and view all the answers

Why should cant excess be kept low on sections carrying predominantly goods traffic?

To minimize wear on inner rail (B) Signup and view all the answers

What is the formula for calculating the length of transition 'L' in terms of cant excess 'Cd'?

L = 0.008 Cd × Vm (D) Signup and view all the answers

What is the purpose of providing a transition length on a curve?

To provide a smooth transition from one cant to another (D) Signup and view all the answers

What is the rail type used in subassembly 7?

60 Kg/m Rail (C) Signup and view all the answers

What is the gradient of subassembly 3?

1 in 12 (B) Signup and view all the answers

What type of sleeper is used in all subassemblies?

PSC sleeper (D) Signup and view all the answers

What is the purpose of SEJs in LWR?

To isolate turnouts from LWR/CWR (D) Signup and view all the answers

What is the rail type used in subassembly 1?

52 Kg/m Rail (B) Signup and view all the answers

What type of web switch is used in subassembly 9?

Zu – 1 – 60 rails (B) Signup and view all the answers

What is common to subassemblies 10 and 11?

Symmetrical split and 1 in 8½ gradient (A) Signup and view all the answers

What is the purpose of turnouts in LWR?

To change the direction of trains (A) Signup and view all the answers

What type of expenditure is mentioned in the context of removing restrictions to slewing?

Moderate expenditure (B) Signup and view all the answers

What is the purpose of measuring and recording the existing Super-elevation?

To identify restrictions to slewing (C) Signup and view all the answers

What is the format of the record obtained from the survey?

A table with columns for Station, Versine, Cant, and Remarks (C) Signup and view all the answers

What is indicated by the 'Remarks' column in the record?

Restrictions to slewing or other relevant information (D) Signup and view all the answers

Why is the versine survey continuous in the case of reverse curves?

Because it is necessary to transfer the survey to the outer rail at points where the curvature changes sign (A) Signup and view all the answers

What is the purpose of recording the features that restrict slewing of the track?

To identify restrictions to slewing and plan for their removal (C) Signup and view all the answers

What is indicated by the 'Versine' column in the record?

The deviation of the track from a true circular arc (C) Signup and view all the answers

What is the significance of the 'G B obligatory point' remark in the record?

It indicates a point where the track is restricted to slewing (C) Signup and view all the answers

What is the pattern of spacing observed in the table?

Constant spacing with occasional variations (A) Signup and view all the answers

What is the value of the cumulative spacing from SRJ at row 14?

8233 (A) Signup and view all the answers

What is the purpose of the annexure pages in the document?

To provide additional information about the table (B) Signup and view all the answers

What is the significance of the value 600 in the table?

It is the standard spacing used in the table (C) Signup and view all the answers

What is the relationship between the spacing and the cumulative spacing from SRJ?

The spacing is always added to the cumulative spacing from SRJ (B) Signup and view all the answers

What is the unit of measurement for the spacing and cumulative spacing from SRJ?

Meters (D) Signup and view all the answers

What is the purpose of the table?

To show the location of tongue rails (D) Signup and view all the answers

What is the significance of the rows in the table?

Each row represents a different location on the railway track (C) Signup and view all the answers

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Study Notes

Cant and Super-elevation

Cant should be rounded off to the multiple of 5 mm.
Maximum cant on curved tracks:
- Broad gauge - Group 'A', 'B', and 'C' routes: 165 mm
- Broad gauge - Group 'D' and 'E' routes: 140 mm
Maximum cant deficiency:
- Routes with sectional speed over 100 km/h: 100 mm
- Other Broad gauge routes: 75 mm
Cant excess should not exceed 75 mm for all types of rolling stock.

Length of Transition Curve and Setting-out Transitions

The desirable length of transition 'L' shall be the maximum of three values:
- L = 0.008 Ca × Vm
- L = 0.008 Cd × Vm
- L = 0.72 × Ca
Criteria for realignment of a curve based on service limit for station-to-station versine variation.

String Lining Operations

Operations involve:
- Survey of the existing curve by measurement of versines
- Determination of the revised alignment and computation of slews, including provision of correct Super-elevation
- Slewing of the curve to the revised alignment
Versine survey of curve:
- Versine readings are taken along the gauge face of the outer rail
- Markings are made on the gauge face of the outer rail at a distance of at least 30 m behind the beginning of the curve and at the end of the curve
- Stations are marked and numbered in white paint on the rail
- Versines are measured to 1 mm accuracy serially at each station from one end of the curve to the other
- Certain features that restrict slewing of the track are recorded
- Existing Super-elevation is measured and recorded against each station

LWR through Points and Crossings

Turnouts shall be isolated from LWR/CWR by provision of SEJs on either side.

Rails and Switches

Various types of rails and switches are listed with their respective characteristics and specifications.

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