  # Problems on Trains - Aptitude Questions and Answers - RejinpaulPlacement 1.
A train 100m long is running at the speed of 30 km/hr. Find the time taken by it to pass a man standing near the railway line. [S.S.C. 2001]

Solution:   Speed of the train = (30 * 5/18) m/sec = (25/3) m/sec.

Distance moved in passing the standing man = 100 m.

Required time taken = 100 / (25/3) = (100 * 3/25) sec = 12 sec. 2.
A train is moving at a speed of 132 km/hr. f the length of the train is 110 metres, how long will it take to cross a railway platform 165 metre long? [ Section Officer's 20013]

Solution:   Speed of train = ( 132 * 5/18) m/sec = (110/3) m/sec.

Distance covered in passing the platform = (110 + 165) m = 275 m.

Therefore, time taken = ( 275 * 3/110) sec = 15/2 sec = 7 ½ sec. 3.
A man is standing on a railway bridge which is 180 m long. He finds that a train crosses the bridge in 20 seconds but himself in 8 seconds. Find the length of the train and its speed.

Solution:   Let the length of the train be x metres.

Then, the train covers x metres in 8 seconds and (x + 180) metres in 20 seconds.

x/8 = (x + 180)/20
=> 20x = 8(x + 180)
=> x = 120

Length of the train = 120 m.

Speed of the train
= (120/8) m/sec = (15 * 18/5) kmph = 54 kmph. 4.
A train 150 m long is running with a speed of 68 kmph. In what time will it pass a man who is running at 8 kmph in the same direction in which the train is going?

Solution:   Speed of the train relative to man
= (68 – 8) kmph
= (60 * 5/18) m/sec = (50/3) m/sec

Time taken by the train to cross the man
= Time taken by it cover 150 m at (50/3) m/sec
= (150 * 3/50) sec = 9 sec. 5.
A train 220 m long is running with a speed of 59 kmph. In what time will it pass a man who is running at 7 kmph in the direction opposite to that in which the train is going?

Solution:   Speed of the train relative to man
= (59 + 7) kmph = (66 * 5/18) m/sec = (55/3) m/sec.

Time taken by the train to cross the man
= Time taken by it to cover 220 m at (55/3) m/sec
= (220 * 3/55) sec = 12 sec. 6.
Two trains 137 metres and 163 metres in length are running towards each other on parallel lines, one at the rate of 42 kmph and another at 48 kmph. In what time will they be clear of each other from moment they meet?

Solution:   Relative speed of the trains
= (42 + 48) kmph = 90 kmph
= (90 * 5/18) m/sec = 25 m/sec.

Time taken by the trains to pass each other
= Time taken to cover (137 + 163) m at 25 m/sec
= (300/25) sec = 12 sec. 7.
Two trains 100 metres and 120 metres long are running in the same direction with speeds of 72 km/hr and 54 km/hr. In how much time will the first train cross the second? [C.B.I. 1997] 