Aptitude Problems on Trains Concepts and Formulas

Points to remember:

Keep same units for all values mentioned in the problem i.e. as per the units of the given answers convert kilometer per hour (km/hr) to meters per second (m/s) and vice versa. In a similar way, convert meter (m) into centimeter (cm) and vice versa. See the examples given below:

Formula to convert Km/hr into m/s:

• 1km is equal to 1000 meters
• 1 hours is equal to 3600 seconds
• 1Km/hr is equal to meter/sec or m/s

So, to convert a value in Km/hr to m/s, we need to multiply it with See the example given below:

60 km/hr* = 16.7 m/s

Formula to convert m/s to Km/hr

• 1 meter is equal to 1/1000 km
• 1 sec is equal to 1/3600 hours
• 1 m/s is equal to

So, to covert a value in m/s to Km/hr, we will multiply it with 18/5. See the example given below:

20 m/s* =72 km/hr

Important facts about moving trains:

1. The distance traveled by a train to cross a pole or person is equal to the length of the train.
2. The distance traveled by train when it crosses a platform is equal to the sum of the length of the train and length of the platform.
3. When two trains are travelling in opposite directions at speeds V1 m/s and V2 m/s then their relative speed is the sum of their individual speeds (V1+V2) m/s.
4. Two trains are travelling in the same direction at V1 m/s and V2 m/s where V1 > V2 then their relative speed will be equal to the difference between their individual speeds (V1-V2) m/s.
5. When two trains of length X meters and Y meters are moving in opposite direction at V1 m/s and V2 m/s then the time taken by the trains to cross each other is =
6. When two trains of length X meters and Y meters are moving in same direction at V1 and V2 where V1> V2 then the time taken by the faster train to cross the slower train =
7. When two trains X and Y start moving towards each other at the same time from points A and B and after crossing each other the train X reaches point B in a seconds and train Y reaches points A in b seconds, then

Train X speed: Train Y speed = b^1/2: a^1/2