Problems on Trains Cheat Sheet
31 Oct 2026
Quick answer
A quick revision cheat sheet on problems on trains for SSC, Banking, Railway and state exams. It covers the km/h to m/s conversion, a train crossing a pole, a train crossing a platform, two trains passing in the same and opposite directions, and the relative-speed idea, with worked examples to revise quickly.
Problems on Trains Cheat Sheet
Quick Revision
Problems on trains are time-speed-distance problems where the moving object has a length, so the distance covered includes the train itself.
1. Unit Conversion
km/h → m/s : multiply by 5/18
m/s → km/h : multiply by 18/52. Crossing a Pole or a Platform
A pole has no length; a platform does:
Crossing a pole : time = (length of train) / speed
Crossing a platform : time = (train + platform length) / speed3. Two Trains Passing
Opposite directions : relative speed = sum of the two speeds
Same direction : relative speed = difference of the two speedsThe distance to clear is the sum of both train lengths.
4. Worked Example
A 120 m train runs at 54 km/h.
Speed = 54 × 5/18 = 15 m/s
Crossing a pole : 120 / 15 = 8 seconds
Crossing a 180 m platform : (120 + 180) / 15 = 20 seconds5. Exam Quick Tips
- Convert km/h to m/s first when lengths are in metres and times in seconds.
- Crossing a pole uses only the train's length; a platform adds its length too.
- For two trains, add the speeds when they meet head-on, subtract when one overtakes the other.
Keep revising with the rest of the Maths section:
How this was made: Drafted with AI assistance; spot-checked by the editor on 31 October 2026.