Railway Bridges Design Quiz and Flashcards

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Questions and Answers

What should not fall within the breathing lengths in LWR/CWR territory?

Glued joints

Level crossings (correct)

Points and crossings

Bridges with ballasted deck

What type of joint shall be provided between the stock rail joint and SEJ, as well as between the crossing and SEJ?

Three rail panel (correct)

Four rail panel

Two rail panel

Single rail panel

What is the type of glued joint that shall be used for track circuiting in LWR/CWR?

G4(L) type

G2(L) type

G3(L) type (correct)

G1(L) type

What factor should be considered while fixing the exact location of SEJ?

Location of various obligatory points Signup and view all the answers

On which type of curves can the conventional SEJ (RT-4160 and RT-4165) be located?

Curves sharper than 0.5° (3500 m radius) Signup and view all the answers

On which type of curves can the improved SEJs (RT-6902, RT-6914, RT-6922, RT-6930) be located?

Curves up to 2° Signup and view all the answers

What is the condition for locating SEJ on curves between 2° and 4°?

With consultation of PCE and RDSO Signup and view all the answers

Which type of bridges can LWR/CWR be continued over?

Bridges with ballasted deck without bearings Signup and view all the answers

What is the maximum allowed length of a single span for bridges with rail-free fastenings and partly box-anchored?

30.5 metre Signup and view all the answers

How many anchoring arrangements are required for central sleepers in end spans?

Two each Signup and view all the answers

What is the standard for track structure in the approaches?

As stated in (1) (b) & (c) Signup and view all the answers

When should the sliding bearings be inspected and cleared of foreign materials?

During the months of March and October each year Signup and view all the answers

How often should the sliding bearings be lubricated?

Once in two years Signup and view all the answers

What is the purpose of centralizing the girders with reference to the location strips on the bearing?

Before laying LWR/CWR Signup and view all the answers

Which type of fastenings are used for the remaining sleepers?

Rail-free fastenings Signup and view all the answers

What is the special feature of the bridges with rail-free fastenings and partly box-anchored?

Sliding bearings at both ends Signup and view all the answers

What is the quantity of Aluminium/steel rod for thermal plugging?

2 Nos. Signup and view all the answers

What is the purpose of the hot sets (chisels) in the tool box?

For emergency use only. Signup and view all the answers

What is the weight of the sledge hammer?

5 kg Signup and view all the answers

What is the quantity of leather washers for pump?

4 Nos. Signup and view all the answers

What is the purpose of the pyrometer/thermal chalk?

For measuring the rail temperature. Signup and view all the answers

What is the quantity of mould shoes?

6 Pairs. Signup and view all the answers

What is the quantity of asbestos gloves?

4 Pairs. Signup and view all the answers

What is the quantity of slag container (bowl)?

2 Nos. Signup and view all the answers

Where should the package containing igniters be kept?

In a steel container Signup and view all the answers

What is the minimum duration of traffic block required for complete operation of welding?

70-75 minutes Signup and view all the answers

When can traffic be allowed after welding of the joint?

After 30 minutes Signup and view all the answers

What should be provided on AT welds that have undertaken traffic equal to or more than 50% of stipulated fatigue life of the rail?

Joggled fish plate with far end bolts Signup and view all the answers

What should be provided on good AT welds on banks having a height of 5 m or more?

Joggled fish plate with clamps Signup and view all the answers

How far away should SEJ be installed from the abutments?

15 metres Signup and view all the answers

What is the maximum gap of Improved SEJ according to Drawing no.RDSO/T-6922 and RDSO/T-6930?

65 mm Signup and view all the answers

What is the reference manual for Alumino Thermic Welding of rails?

Manual for Fusion Welding of Rails by Alumino Thermic Process Signup and view all the answers

What is the initial gap to be provided at Zone IV?

7.0 cm Signup and view all the answers

What should be done to a Thermit welding done in-situ?

It should be joggled fish plated with two clamps and supported on wooden blocks Signup and view all the answers

Where else should joggled fish plate with clamps or two far end bolts on good AT welds be provided?

On bridges having a length of waterway as 100 m or more Signup and view all the answers

What type of bearings are used on both sides of the girder?

Sliding bearings Signup and view all the answers

At what distance from the abutments can welded rails be provided with rail-free fastenings and SEJ?

30 m Signup and view all the answers

How many sleepers are used for box-anchoring the rail at the fixed end of the girder?

4 sleepers Signup and view all the answers

What is the gap of SEJ used in Zone II?

120 mm Signup and view all the answers

What is the overall length of the bridge used in Zone II?

110 m Signup and view all the answers

Study Notes

Bridge Construction

Bridges with rail-free fastenings and partly box-anchored can have a single span not exceeding 30.5 meters with sliding bearings at both ends.
The overall length of the bridge should not exceed the maximum as provided in Table-1.
Central sleepers shall be anchored with an anchoring arrangement, and the remaining sleepers shall be provided with rail-free fastenings.

Sliding Bearings

Sliding bearings shall be inspected during the months of March and October each year and cleared of all foreign materials.
Lubrication of the bearings shall be done once in two years.

AT Portion and Welding

AT Portion should not be transported in passenger coaches.
The package containing igniters should be kept in tin cases/steel containers.
For detailed guidelines on storage and transportation, AT Welding Manual may be referred.

Equipment, Staff, and Traffic Block for Welding

The list of one set of AT welding equipment by short pre-heating process is given in Annexure - 3/2.
The composition of Thermit welding team is given in Annexure - 3/3.
A minimum traffic block of 70-75 minute duration is required for complete operation of welding and to ensure good quality of AT weld.
Traffic can be allowed only after 30 minutes have elapsed after welding of the joint, and suitable speed restriction shall be imposed until the grinding operation is completed.

Execution of Welding and Precautions

Alumino Thermic Welding of rails may be carried out in accordance with the detailed procedure laid down in the ‘Manual for Fusion Welding of Rails by Alumino Thermic Process’.
Joggled fish plates with clamps or two far end bolts shall be provided on AT welds, which have undertaken traffic equal to or more than 50% of stipulated fatigue life (GMT) of the rail.

Level Crossings and Points and Crossings

Level crossings situated in LWR/CWR territory shall not fall within the breathing lengths.
In case, LWR is terminated near Points & Crossings, one three rail panel (39 m) shall be provided between stock rail joint (SRJ) and SEJ as well as between the crossing and SEJ.
In case, LWR/CWR is taken through Points & Crossings, the provisions contained in RDSO report no.CT-48 shall be followed.

Provision of Glued Joints

All insulations for track circuiting in LWR/CWR shall be done by providing glued joints of G3(L) type.

Location of SEJ

The exact location of SEJ shall be fixed taking into account the location of various obligatory points such as level crossings, bridges, points and crossings, gradients, curves, and insulated joints.
The conventional SEJ (RT-4160 and RT-4165) with straight tongue and stock shall not be located on curves sharper than 0.5° (3500 m radius).
The improved SEJs (RT-6902, RT-6914, RT-6922, RT-6930) may be located on curves up to 2°.
SEJ beyond 2° and up to 4° shall be laid with approval of PCE in consultation with RDSO.

Bridges with Ballasted Deck

LWR/CWR can be continued over bridges with ballasted deck without bearings like slabs, box culverts, and arches.
The rail shall be box-anchored on four sleepers at the fixed end of the girder if the girder is supported on rollers on one side and rockers on other side.
In case of girder supported on sliding bearings on both sides, the central portion of the welded rails over each span shall be box-anchored on four sleepers.

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Description

This quiz covers the design specifications for railway bridges, including rail-free fastenings, box-anchored bridges, and sliding bearings. It also includes stipulations for central sleepers and anchoring arrangements.

Railway Bridges Design