Rolling Stock Inspection Chapter 3

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Questions and Answers

What is the primary function of laminated springs in four-wheeler stock?

To increase vehicle speed on uneven tracks

To ensure normal functioning and load transmission (correct)

To minimize weight and enhance fuel efficiency

To provide better aesthetics for the vehicle

What can occur if the defects in springs affect their functioning?

Prone to derailment due to lack of dampening force (correct)

Improved traction on wet surfaces

Enhanced comfort for passengers

Increased fuel consumption

What is the maximum allowable difference in working camber among the four springs on the same vehicle?

10 mm

5 mm

20 mm

13 mm (correct)

What type of springs is mostly used in coaches instead of laminated springs?

Coil springs Signup and view all the answers

What aspect of spring design must be consistent to prevent derailment?

Working camber of the springs Signup and view all the answers

What is the acceptable maximum measurement for the broad gauge wheel gauge?

1602 mm Signup and view all the answers

What must be ensured before measuring the wheel gauge to avoid erroneous readings?

The back surface of wheels is cleaned thoroughly. Signup and view all the answers

If the wheel gauge exceeds the maximum permissible limit, which of the following issues might occur?

The wheel may hit the nose of crossing. Signup and view all the answers

What is the primary purpose of measuring the wheel gauge?

To check potential clearance issues at crossings. Signup and view all the answers

What can happen if the wheel gauge is below the minimum value?

The wheel may hit the back of a tongue rail. Signup and view all the answers

How many points on a wheel set should the wheel gauge be measured for accuracy?

Four points Signup and view all the answers

Which of the following is NOT a main item of inspection for rolling stock?

Train weight Signup and view all the answers

What is the variation in wheel gauge that can occur under tare load conditions for a 15 ton BG axle?

About 3 mm Signup and view all the answers

Under which condition must the wheel gauge tolerances of 1600 ± 2 mm be checked?

No-load conditions Signup and view all the answers

What is a consequence of a bent axle during motion?

Severe vibrations Signup and view all the answers

What feature of the tyre profile avoids sharp edges according to the specifications?

A chamfer of 6 mm Signup and view all the answers

What is the purpose of the upward inclination in the tyre profile?

To ensure central positioning on the track Signup and view all the answers

How is a bent axle typically confirmed?

Checking on a sensitive machine Signup and view all the answers

What is the route radius provided at the bottom of the flange for B.G. tyres?

15 mm Signup and view all the answers

Which statement is TRUE regarding the measurement of wheel gauge in the horizontal plane?

It eliminates the effect of bending of the axle. Signup and view all the answers

What happens when small burs project beyond the outer surface of the wheel?

They may create sharp edges. Signup and view all the answers

What is the maximum allowed difference in wheel diameter for four-wheeled trolleys on the same axle for BG?

13 Signup and view all the answers

Which type of vehicle requires the maximum wheel diameter variation of 25 mm?

Four wheeled units Signup and view all the answers

What is the minimum lateral clearance between the axle box lug and the horn cheek for box type trolleys?

20 mm Signup and view all the answers

What is the maximum lateral clearance between the axle guard and the axle box groove?

10 mm Signup and view all the answers

According to the specified limits, what is the total lateral clearance maximum for axle box regarding its groove?

10 mm Signup and view all the answers

What will happen if the lateral clearance goes below the minimum limit?

Freedom of wheels gets restricted Signup and view all the answers

During periodic overhaul, which wheel type has the lowest maximum diameter variation limit for six-wheeled units?

Both BG and MG Signup and view all the answers

What is the maximum lateral clearance indicated for a minimum of 12 mm longitudinal clearance?

18 mm Signup and view all the answers

Which type of trolley is subject to the same wheel diameter variation limits as six-wheeled trolleys?

Both four and six wheeled trolleys Signup and view all the answers

What is the prescribed maximum difference in wheel diameter for six-wheeled trolleys on the same axle for both BG and MG?

6 mm Signup and view all the answers

What issue arises if bent axle guards cannot move freely?

The axle box may get jammed. Signup and view all the answers

What is the minimum buffer projection for short case buffers?

445 mm Signup and view all the answers

What must be ensured when measuring buffer height?

Buffers should be checked for drooping. Signup and view all the answers

What is the consequence of buffers being displaced more than the specified amounts?

They can cause the vehicle to derail. Signup and view all the answers

What does drooping of a buffer indicate?

The buffer height measurement will be inaccurate. Signup and view all the answers

Which packing piece is used for goods stock to adjust buffer heights?

Between axle box crown and bearing spring buckles. Signup and view all the answers

What can cause the adjacent stock buffers to be at different levels?

Different conditions of loading. Signup and view all the answers

What action is not allowed for dead buffers according to guidelines?

They cannot be permitted from the sick line. Signup and view all the answers

How can buffer heights be restored to maximum permissible limits?

By inserting a packing piece. Signup and view all the answers

What force is exerted when buffers compress due to track sag or brake application?

Compressive forces. Signup and view all the answers

Which of the following describes the lateral clearance between axle guard and axle box groove?

10 mm maximum Signup and view all the answers

What happens if the lateral clearance goes below the minimum limit specified for axle box lugs?

Restricted freedom of wheels Signup and view all the answers

For six-wheeled units, what is the maximum allowable wheel diameter difference that can be observed?

6 mm Signup and view all the answers

What is the prescribed maximum difference in wheel diameter for four-wheeled units on the same axle?

25 mm for BG, 13 mm for MG Signup and view all the answers

What is the purpose of inspecting the wheel gauge at four points on a wheel set?

To assess variations in the wheel gauge for safety Signup and view all the answers

What could be a consequence of having a wheel gauge greater than the maximum permissible limit?

Potential contact of wheels with structures at crossings Signup and view all the answers

Why is it important to clean the back surface of wheels before measuring the wheel gauge?

To ensure accurate readings by removing debris Signup and view all the answers

If the wheel gauge is measured below the minimum value, what situation may arise?

Damage to the tongue rail while navigating switches Signup and view all the answers

Which factor must be considered when measuring wheel gauge to avoid errors?

Consistency in the method of measuring across different wheel sets Signup and view all the answers

What is the correct action if variations in wheel gauge are detected?

Conduct a detailed investigation to assess implications Signup and view all the answers

What does the term 'slackness of gauge' indicate during the inspection process?

The wheels may not provide adequate grip on the rail Signup and view all the answers

What is the main consequence of a wheel gauge exceeding the acceptable tolerances?

Potential derailment of the coach Signup and view all the answers

What method is recommended to confirm whether an axle is bent?

Using a sensitive machine or measuring table Signup and view all the answers

What feature of the tyre profile is designed to prevent small burs from projecting beyond the outer surface of the wheel?

The chamfer of 6 mm at 45 degrees Signup and view all the answers

Why must the wheel gauge tolerances be checked under 'No-load' conditions?

To accurately assess the bending effect of a loaded condition Signup and view all the answers

What is the effect of the upward inclination of 1 in 20 in the tyre profile?

It aligns the wheels centrally on the track Signup and view all the answers

The variation in wheel gauge under loaded conditions has what primary implication?

It is negligible and does not impact safety Signup and view all the answers

What is the standard route radius provided at the bottom of the flange for B.G. tyres?

15 mm Signup and view all the answers

What happens to an axle once it becomes bent during motion?

It causes severe vibrations and wobbling Signup and view all the answers

What measurement cannot be relied upon to determine the true condition of an axle under load?

Vertical plane measurements Signup and view all the answers

What is the threshold height for a wheel flange to be classified as thin for B.G.?

16 mm Signup and view all the answers

Which of the following describes the condition of a sharp flange?

The radius at the tip is less than 5 mm Signup and view all the answers

What additional condition is described when a flange is referred to as worn out?

The radius at the root is less than 13 mm Signup and view all the answers

What measurement indicates the presence of a deep flange?

Greater than 35 mm from the top to the tread Signup and view all the answers

What common defect is associated with flat places appearing on tyres?

Increased lateral play and instability Signup and view all the answers

What indicates that a flange has sharp edges?

Radius at the tip is less than 5 mm Signup and view all the answers

What is the maximum permissible flange thickness for B.G. to avoid being classified as thin?

16 mm Signup and view all the answers

When is a flange considered deep based on its depth measurement?

Greater than 35 mm from top to tread Signup and view all the answers

What defect is measured at a distance of 13 mm below the flange tip?

Thin flange Signup and view all the answers

What factor does a thin flange increase between the wheel set and the track?

Lateral play Signup and view all the answers

What effect does a hollow tyre have on the conicity of the wheel tyre?

It increases the conicity. Signup and view all the answers

What can happen to a wheel with a false flange while negotiating crossing points?

It can get wedged between the rails, causing lifting. Signup and view all the answers

What is the maximum permissible flatness on a B.G. wheel tyre for goods stock?

60 mm Signup and view all the answers

How does wheel flatness impact the rails?

It increases contact stresses damaging the rails. Signup and view all the answers

At which measurement distance should wheel diameter be measured for B.G. wheels?

63.5 mm from the inside face Signup and view all the answers

What is a potential consequence of excessive conicity due to wheel wear?

Increased risk of derailment. Signup and view all the answers

What is a common effect of running on a false flange?

Increased likelihood of wheel lift. Signup and view all the answers

What range is acceptable for the difference in wheel diameter for four-wheeled trolleys on the same axle for B.G.?

25 mm Signup and view all the answers

What happens when a wheel is subject to a high degree of flatness?

It may lead to rail fracture. Signup and view all the answers

What does a wheel travelling on a false flange instead of the tread lead to during switching?

Sudden lifting and dropping of the wheel. Signup and view all the answers

Study Notes

Chapter 3: Inspection of Rolling Stock

Rolling stock involved in accidents must be inspected in the presence of supervisors.
Inspection results are recorded in a specific format (Appendix A).
Key inspection items include wheel gauge.

3.1 Wheel Gauge

Wheel gauge is the distance between inside faces of the flanges on the right and left side wheels of an axle.
Wheel gauge values should be consistent at four 90-degree points on a wheel set.
Acceptable variations in wheel gauge are based on tolerances in Table 3.1 (IRCA Part III, Para 2.8.7).

Figure 3.1: Measurement of Wheel Gauge

Wheels are gauged at three or four quarters (if possible).
Records should indicate tightness/slackness of gauge and any wheel shifting on the axle.
Wheel surfaces must be cleaned before measurement to prevent inaccurate readings.

3.1.1 Wheel Gauge Limits

If wheel gauge exceeds permissible limits, a newer wheel might hit the crossing nose.
Wheel gauge is a parameter affecting clearance at check rail opposite the crossing nose.

3.1.2 Wheel Gauge Minimum Limits

If wheel gauge is less than minimum, there's a possibility of the wheel hitting the back of a tongue rail during switch passages.

3.1.3 Variation in Wheel Gauge

Variation in wheel gauge after lowering the coach body was examined by RDSO Lucknow and circulated to relevant railways (letter no. MC/WA/GENL dated 27.6.88).
Wheel gauge variation under no-load and loaded conditions was examined by RDSO.
A 15-ton BG axle under tare load condition might have a 3mm variation in wheel gauge. This variation is due to axle bending under coach load, but variation in horizontal dimensions has no bearing on safety.

3.2 Bent Axle

Bent axles cause wobble and vibrations during motion.
Axles should be checked on sensitive machines or tables.

3.3 Tyre Profile

The outer periphery of a wheel in contact with the rail is the tyre profile.
Standard B.G. (Broad Gauge) tyre profile is shown in Figure 3.2.
Key characteristics include a 6mm chamfer at 45 degrees on the outer edge and a 1 in 20 upward inclination.

3.3.1 Tyre Chamfer

A 6mm, 45-degree chamfer prevents sharp edges and burrs (metal chips) on the outer wheel surface.

3.3.2 Tyre Inclination

A 1 in 20 upward inclination ensures wheels stay centered on the track.
Enables outer wheels to travel on a larger diameter compared to inner wheels on curves.

3.3.3 Route Radius

A root radius of 15mm is provided at the bottom of B.G. wheel flanges.

3.3.4 Wheel Flange Height

Wheel flange height is measured from wheel tread and is 28.5mm for B.G.

3.4 Wheel Defects

Examination of suspected wheels involves checking for:
- Condemnation limits
- Flat spots on tyre/skidding
- Flanges (sharp/deep/thin)
- Small flange radii at the root
- Slack/tight gauge
- Cracks

3.4.1 Thin Flange

Flange thickness reduced to less than 16mm is considered a thin flange.
Measure flange thickness 13mm below the flange tip (Figure 3.5).

3.4.2 Sharp Flange

Flange wears down to a radius of less than 5mm resulting in a sharp edge.
Risk of wheel riding over chipped tongue rail.

3.4.3 Worn Out Flange

Flange root radius reduces to less than 13mm, increasing lateral play between wheel set and track.

3.4.4 Deep Flange

Flange depth measured from flange top to a point on the wheel tread exceeding 35mm is considered deep flange (Figure 3.6).
Deep flange can cause the wheel to ride on the fish plate, stressing the track.

3.4.5 False Flange/Hollow Tyre

Projection of wheel tread below tyre hollow exceeding 5mm creates a false flange (Figure 3.7).
Hollow tyre can lead to false flange creation and increased potential for derailment. This effect is independent of angularity or eccentricity. It increases the wheel conicity, decreases the critical speed of rolling stock, and increases flange forces which increase derailment risk.

3.4.6 Flat Places on Tyre

Maximum permissible flatness on B.G. wheel tyres is 60mm (Figure 3.9).

3.4.7 Difference of Wheel Diameter on Tread

Wheel diameter is measured on the tread 63.5mm from the inside face for B.G. wheels and 57mm for M.G. wheels.
Measurements are taken 180° apart on each wheel (Figure 3.10).

3.5 Axle Box Lateral and Longitudinal Clearances

Lateral play between B/Brass and Journal collar (5mm min, 10mm max).
Total lateral clearance between Axle guard and Axle box grove (maximum 10mm).
Lateral/longitudinal clearance between axle box lug and horn cheek (20mm min/12mm, 25mm max/18mm).

3.6 Buffing Gear

Buffer projection limits from headstock (max/min).
Buffer heights in BG stock have limits and are measured on level tracks.
Buffer placement from centre of buffer socket to rail head.
For Goods stock, packing piece between axle box crown and bearing, and springs.
For ICF coaching stock, packing piece between lower spring and axle box wing.

3.7 Spring and Spring Gear

Laminated springs are standard in four-wheelers.
Coaches typically use coil springs.

3.7.1 Spring Defects

Spring defects hinder normal functioning, affecting load transmission and wheel adjustment to track irregularities.
Lack of proper damping leads to higher proneness to derailment.

3.7.2 Spring Camber Variation

Camber variation (difference in working camber amongst the four springs under load) should not exceed 13mm to prevent derailment.

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This quiz covers the essential aspects of rolling stock inspection, focusing specifically on wheel gauge measurements and tolerances. Learn about the importance of consistency in wheel gauge and the procedures necessary for accurate inspections. Key concepts include acceptable variations and the significance of maintaining proper wheel gauge standards.