Tips for train questions:

1.when a train passes a man,tower,poll,we will take length of train as distance.
2. When a train crosses a platform/bridge of particular length. We will add both train and bridge/platform length for distance. Speed of train as a speed. Time is given in questions.
* be aware about units. One thing always different.
3. When two train running in same direction.
We will add length of both trains,
but we will substrate speeds (from more to less).
4. When two trains runing in opposite direction. We will add the speed.
S= s1 + s2.
S = distance/time
for distance add lengths of both trains.
5. When a train driver passes a passenger of another train sitting at window.and train runing in opp. Direction.
Than we take the length of the train in which driver is sitting. Only this length be the distance.
For speed, we will add speed of both the trains. As they r movinp in opp. Direction.
Km/hr change to m/s. Always u find one unit different.
Speed = distance/time