A train is a long vehicle, which even while in motion, is visible for a longer period of time. This gives the observer ample time to observe the necessary attributes to calculate the speed of the train. If the distance covered by the train in unit time is guessed or known correctly, the speed of the train can be determined easily.
Moreover, devices like radar speed guns can be put to use to measure the speed of the train. Also, many mobile applications that help accurately measure the speed of moving objects are available on the internet and official application stores easily.
