The length of train is equal to the length of the platform. Suppose the train is running at a speed of 72 km/hr and it crosses a platform in 2 minutes. What is then the length of the train?

Speed in m/sec = 36km/hr x (5/18) = 10 m/sec
Given, Time taken by train to cross the platform = 2 min = 120 sec
Therefore, the distance covered by train in crossing the platform = 10 m/sec x 120 sec = 1200 m
Now, distance covered by train in crossing the platform = Length of train + Length of Platform
Given, Length of train = Length of Platform = x
Therefore, 2x = 1200
so, x = Length of train = 1200/2 = 600 m