Quantitative Aptitude

Problems on Trains questions with solutions

Train questions are the most common speed–time–distance type in SSC and railway papers. They all reduce to one idea: what distance does the train have to cover, and at what relative speed.

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Prepared by the CBTAdda content team · Updated 28 October 2026 · How we check our content

How to solve problems on trains questions

Convert km/h to m/s by multiplying by 5/18 (72 km/h = 20 m/s).
Crossing a pole or a person: distance = length of the train. Crossing a platform or another train: add both lengths.
Trains in opposite directions: add speeds. Same direction: subtract them.

Common trap: Forgetting to add the platform length, or mixing km/h with metres, gives exactly the wrong options the examiner has prepared.

12 practice questions

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Two trains 120 m and 100 m long run at 72 km/h and 36 km/h in the same direction. How long will they take to cross each other?
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Answer: (A) 22 s. Relative speed = 72 − 36 = 36 km/h = 10 m/s. Total length = 220 m. Time = 220 ÷ 10 = 22 seconds.
Two trains 240 m and 200 m long run at 108 km/h and 36 km/h in the same direction. How long will they take to cross each other?
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Answer: (C) 22 s. Relative speed = 108 − 36 = 72 km/h = 20 m/s. Total length = 440 m. Time = 440 ÷ 20 = 22 seconds.
A train 330 m long runs at 108 km/h. How long will it take to cross a pole?
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Answer: (D) 11 s. 108 km/h = 108 × 5/18 = 30 m/s. Time = 330 ÷ 30 = 11 seconds.
Two trains 480 m and 395 m long run at 72 km/h and 54 km/h in opposite directions. How long will they take to cross each other?
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Answer: (B) 25 s. Relative speed = 72 + 54 = 126 km/h = 35 m/s. Total length = 875 m. Time = 875 ÷ 35 = 25 seconds.
Two trains 40 m and 35 m long run at 72 km/h and 54 km/h in the same direction. How long will they take to cross each other?
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Answer: (B) 15 s. Relative speed = 72 − 54 = 18 km/h = 5 m/s. Total length = 75 m. Time = 75 ÷ 5 = 15 seconds.
Two trains 590 m and 490 m long run at 90 km/h and 54 km/h in opposite directions. How long will they take to cross each other?
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Answer: (A) 27 s. Relative speed = 90 + 54 = 144 km/h = 40 m/s. Total length = 1080 m. Time = 1080 ÷ 40 = 27 seconds.
A train 370 m long runs at 108 km/h. How long will it take to cross a platform 560 m long?
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Answer: (B) 31 s. Distance = 370 + 560 = 930 m. Speed = 30 m/s. Time = 930 ÷ 30 = 31 seconds.
Two trains 20 m and 20 m long run at 36 km/h and 54 km/h in the same direction. How long will they take to cross each other?
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Answer: (B) 8 s. Relative speed = 36 − 54 = 18 km/h = 5 m/s. Total length = 40 m. Time = 40 ÷ 5 = 8 seconds.
A train 500 m long runs at 90 km/h. How long will it take to cross a pole?
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Answer: (C) 20 s. 90 km/h = 90 × 5/18 = 25 m/s. Time = 500 ÷ 25 = 20 seconds.
Two trains 390 m and 310 m long run at 72 km/h and 54 km/h in opposite directions. How long will they take to cross each other?
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Answer: (B) 20 s. Relative speed = 72 + 54 = 126 km/h = 35 m/s. Total length = 700 m. Time = 700 ÷ 35 = 20 seconds.
A train 225 m long runs at 54 km/h. How long will it take to cross a pole?
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Answer: (C) 15 s. 54 km/h = 54 × 5/18 = 15 m/s. Time = 225 ÷ 15 = 15 seconds.
A train 90 m long runs at 36 km/h. How long will it take to cross a platform 60 m long?
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Answer: (A) 15 s. Distance = 90 + 60 = 150 m. Speed = 10 m/s. Time = 150 ÷ 10 = 15 seconds.