Problems on Trains
Crossing poles, platforms and trains
Problems on trains are a classic topic in aptitude tests that involve calculating time, speed, and distance in scenarios involving trains crossing various objects like poles, platforms, bridges, and other trains. These problems test your understanding of relative speed and distance concepts in practical situations.
Key formulas and rules
Key concepts
Crossing a Stationary Object (Pole/Signal Post)
When a train crosses a stationary object like a pole or signal post, the distance covered equals the length of the train itself. The object has negligible length, so time taken = Length of train / Speed of train. This is the simplest case of train problems.
Crossing a Platform or Bridge
When a train crosses a platform or bridge, the total distance to be covered is the sum of the train's length and the platform/bridge length. The time taken = (Length of train + Length of platform) / Speed of train. This is because the train is considered to have completely crossed only when its rear end clears the far end of the platform.