Braking and Mechanical Considerations Interview Questions and Answers:

1. Why ordinary mechanical braking cannot be totally replaced by electrical braking ?

Ans. Because electric braking cannot hold the vehicle stationary.

2. On what factors does the amount of energy returned to the line depend ?

Ans. The amount of energy returned to the line depends upon

  • the initial and final speeds during regenerative braking
  • the train resistance and gradient of the track also in case the train is moving down the gradient and
  • efficiency of the system.

3. Why is regenerative braking not recommended for tramways and trolley buses ?

Ans. Because it will unnecessarily increase the capital cost as well as enhance the operating problems.

4. What is meant by mechanical regenerative braking ?

Ans. During coasting a part of the stored energy (kinetic energy) is utilized in propelling the train against frictional and other resistances to motion and, therefore, speed falls. Thus coasting may be considered as a form of mechanical regenerative braking.

5. Why gear drive is necessary ?

Ans. The size of the motor is reduced with the increase in speed for a given output, so gear drive is necessary to reduce the size of the motor for given output by operating it at higher speed.

6. Why is master controller usually equipped with ‘dead man’s handle’ ?

Ans. So as to stop the train in case the driver faints or becomes incapacitated.

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