Railway Adhesion and Wheel Slip Quiz

A measure of the frictional force between a wheel and rail.

Coefficient of adhesion at the start of motion.

Coefficient of adhesion at speed V.

Wet, oily, dusty rails, leaves, coal dust, poor rail/wheel contact, worn tracks, wheel problems lower friction.

The angle between wheel flange and rail gauge face on curves.

Shifting of weight on a train as it negotiates curves; impacts traction.

Distance between bogie wheels. Affects weight transfer effects.

Reduces load on the leading bogie, increasing load on the trailing bogie.

Nose direction affects axle load: towards motion increases load, opposite motion decreases it.

Calculated as 4.1 tonnes determined by its formula (calculated on the given text).

Torque from traction motors causes weight shift between bogies.

Subtractive from leading axle weight, increasing wheel slip tendency.

Adds to leading axle weight, improving adhesion and reducing slipping.

Can cause detachment between rail and wheel.

Maximum possible tractive effort (before slippage). Calculated as (No. of axles x Min.Net load on axle)

Max. T.E. values of WAG-7 (42.5 t) are higher than WAG-5 (32 t for the stated conditions), illustrating better load capacity and adhesion.

Equalizers hung directly on axle boxes, supported by a link and compensating beam arrangement. Distributes vertical load equally on all axles.

Two sets of equalizer beams between the end and middle axle. It provides a different load distribution method than WAG-7.

4 side bearers per bogie, supporting the full vertical load; centre pivot carries no vertical load.

Centre pivot (60%) and 2 side bearers(40%) share the vertical load.

Improved rail-wheel contact, leading to better adhesion and reduced loss of contact.

3800mm wheel base (1900 + 1900).

Primary and secondary suspension with helical springs and lateral friction dampers in the secondary suspension. Features a bolster support.

A type of bogie found in WAM-4 and WAG-5 locos. characterized by side bearers carrying 40% and centre pivot carrying 60% of the load.

Mechanical components in bogies that reduce vibration.

Limit the sideways swaying motion of the train.

The difference between the speed of a wheel and the speed of the train. This difference is called slip speed or creep, and it's important for traction and braking.

The maximum amount of slip speed before wheel slippage occurs. This speed is determined by track conditions and train speed.

A system that monitors wheel slip and prevents it by adjusting the speed of individual wheels.

A system that uses radar to measure train speed and wheel speeds to control creep and prevent wheel slippage.

A system that uses feedback from the train's traction motors to adjust wheel speed and prevent slippage.

The primary suspension uses springs and dampers to isolate the bogie from the locomotive body, absorbing shocks and vibrations from the track.

The secondary suspension, also using springs and dampers, further isolates the locomotive body from the bogie, providing additional comfort and stability.

Yaw dampers control the rotation of the bogie around its vertical axis, enhancing directional stability and preventing unwanted turning.

In WAP-5 locomotives, the motors are suspended independently from the axles, allowing for smoother operation and reduced wear.

In WAG-9 locomotives, the motors are directly mounted to the axles, providing a more rigid connection.

This curve shows how much force the locomotive can exert at different speeds. A steeper curve indicates a quicker response to wheel slip.

Series connection means all motors are in a chain, while parallel connection means motors are connected side-by-side. Parallel offers better adhesion.

This control method uses resistors to adjust the motor's power, causing sudden changes in tractive effort, reducing average TE and adhesion.

AC locomotives use this method to adjust motor power, offering more precise but still discrete steps, improving average TE and adhesion.

Weight transfer is the shifting of weight on a train due to forces like acceleration, braking, or negotiating curves. This impacts traction and can cause wheel slip.

Weight transfer between bogie axles and between bogies can be significant, especially during acceleration or braking. This affects the locomotive's ability to maintain traction.

Weight transfer is reduced by using resilient components to connect the bogies, designing for a low traction point, and incorporating special suspension systems.

Traction motor noses are the ends of the traction motors attached to the axles. Their direction affects the weight transfer between the bogies.

If traction motor noses point towards the direction of motion, it increases the load on the axle, but if they point opposite, it decreases the load.

Factors such as the height of the drawbar, distance between loading points on the bogie, secondary suspension, and the direction of the traction motor noses all influence weight transfer.

Reducing weight transfer is crucial for improving traction and preventing wheel slip. This ensures efficient and reliable train operation.

The force from the drawbar connecting locomotives pulls the trailing bogie more heavily, decreasing load on the leading bogie.

The maximum force a loco can exert without wheel slip, calculated by multiplying the number of axles by the minimum load on each axle.

Sudden bumps on the track can momentarily detach the rail from the wheel, potentially causing loss of traction.

WAG-7 has a higher maximum tractive effort compared to WAG-5 due to its superior adhesion design, making it more powerful.

A system that ensures optimal traction by managing the difference between the wheel speed and the vehicle speed, maximizing adhesion under varying circumstances, such as poor rail conditions.

The difference between the speed of a wheel and the speed of the train. This difference is called slip speed or creep and is related to the force needed to move the train.

These bogies feature a unique design with side bearers carrying 100% of the vertical load, while the center pivot only carries the traction/brake effort (TE/BE). This even distribution of load ensures better adhesion and reduces the chances of losing rail-wheel contact.

These bogies use a different approach compared to WAG-7, with the side bearers carrying 40% of the vertical load and the center pivot bearing the remaining 60%. This distribution influences adhesion and impacts weight transfer.

The primary suspension is the first layer of shock absorption between the bogie and the locomotive's body. It uses springs and dampers to reduce the impact of track irregularities, ensuring smoother ride and less stress on the train.

The secondary suspension works in tandem with the primary suspension, adding another layer of damping and isolation between the bogie and the body. It further reduces vibrations and ensures stability.

A bolster is a structural component in some bogie designs that provides additional support and stability. It connects the bogie frame to the locomotive body.

Lateral dampers help control the sideways swaying motion of the train. They limit the rocking or tilting movements that might cause instability and reduce comfort.

WAG-7 bogies have equal wheel base (1900mm + 1900mm), meaning both sets of wheels are equally spaced. WAG-5 trimount bogies have unequal wheel base (1702mm + 2108mm), leading to different weight distribution and potentially higher weight transfer.

Rubber thrust pads are used in the primary suspension, often in bearing systems to reduce friction and dampen shocks. They help maintain smooth operation of the axles and minimize wear and tear.

Flexi-coil bogies use helical springs in their primary suspension, which offers better flexibility and adaptability compared to traditional setups. This enhances comfort, absorbs shocks, and contributes to better stability.

The force exerted by the locomotive to pull the train, measured in tonnes.

A graph that shows the relationship between the tractive effort and the speed of the locomotive.

Motors are independently suspended from the axles to allow for smoother operation and reduced wear.

Motors are directly mounted to the axles, providing a more rigid connection.

Shifting of weight on a train due to forces like acceleration, braking or negotiating curves, impacting traction and potentially causing wheel slip.