Study Material — 13 PYQs (2021–2021) · Concept Notes · Shortcuts
SSC CPO Trains is a frequently tested subtopic — 13 previous year questions from 2021–2021 papers are included below with concept notes, key rules and shortcut tricks.
13 questions from actual SSC CPO papers · all shown free · click option to reveal solution
Exam Q 12021Previous Year Pattern
A train 100 m long crosses another train 150 m long moving in the opposite direction in 10 seconds. If the first train travels at 54 km/h, what is the speed of the second train in km/h?
Exam Q 22021Previous Year Pattern
Train A and Train B are moving in the same direction on parallel tracks. Train A travels at 72 km/h and Train B travels at 54 km/h. If Train A is 500 m behind Train B, how long will it take for Train A to catch up with Train B?
Exam Q 32021Previous Year Pattern
A train passes a stationary pole in 8 seconds. If the train is 240 m long, what is its speed in km/h?
Exam Q 42021Previous Year Pattern
A train 150 m long is moving at 72 km/h. How long will it take to cross a platform that is 350 m long?
Exam Q 52021Previous Year Pattern
Two trains are moving towards each other on parallel tracks. Train A travels at 60 km/h and Train B travels at 40 km/h. If they are 300 km apart, how long will it take for them to meet?
Exam Q 62021Previous Year Pattern
A train travels 288 km in 4 hours. What is the speed of the train in m/s?
Exam Q 72021Previous Year Pattern
A train travels 240 km in 4 hours. If the train increases its speed by 20%, how much distance will it cover in 5 hours at the new speed?
Exam Q 82021Previous Year Pattern
Two trains start from the same station at the same time. Train M travels at 50 km/h and Train N travels at 70 km/h, both in the same direction. After 3 hours, Train N stops for 30 minutes. How much further ahead is Train N than Train M when Train N resumes its journey?
Exam Q 92021Previous Year Pattern
Train X and Train Y are moving in the same direction on parallel tracks. Train X (length 120 m) travels at 80 km/h, and Train Y (length 80 m) travels at 60 km/h. How long will it take for Train X to completely overtake Train Y?
Exam Q 102021Previous Year Pattern
A train 200 m long takes 20 seconds to pass a man standing on the platform. The same train takes 50 seconds to completely cross a bridge. What is the length of the bridge?
Exam Q 112021Previous Year Pattern
Two trains start simultaneously from stations X and Y, which are 360 km apart. Train P travels from X towards Y at 60 km/h, and Train Q travels from Y towards X at 40 km/h. After how many hours will they meet?
Exam Q 122021Previous Year Pattern
Two trains, A and B, start simultaneously from stations X and Y respectively, which are 480 km apart. Train A travels at 60 km/h towards Y, while train B travels at 40 km/h towards X. After how much time will they meet, and at what distance from station X?
Exam Q 132021Previous Year Pattern
Two trains start from the same station at the same time. Train X travels at 80 km/h, and train Y travels at 60 km/h, both in the same direction. After 3 hours, train X stops for 30 minutes due to a breakdown. Train Y continues without stopping. How far apart will the two trains be 5 hours after they started?
Concept Notes
Trains— Rules & Concept
Core ConceptRead this first — the foundation of the topic
Core Concept
Train problems involve calculating time taken by trains to cross objects like poles, platforms, bridges, or other trains. The key is understanding that trains have length, unlike point objects
Key Rules
When a train crosses a stationary object like a pole, it travels a distance equal to its own length. When crossing a platform or bridge, it travels its own length plus the length of the platform/bridge. For two trains, use relative speed concept.
Formula BlockMemorise — at least one formula appears in every paper
Time = Distance/Speed
Speed = Distance/Time
Relative Speed (same direction) = |S1 - S2|
Relative Speed (opposite direction) = S1 + S2
Speed conversion: km/hr to m/s multiply by 5/18, m/s to km/hr multiply by 18/5
Exam PatternsWhat examiners ask — read before attempting PYQs
SSC CGL typically asks 1-2 train problems per paper. Common question types include trains crossing poles, platforms, bridges, and other trains. Questions often involve unit conversions and relative motion.
ShortcutsUse these to save 30–60 seconds per question
- The 5/18 Rule: To convert km/hr to m/s, multiply by 5/18. To convert m/s to km/hr, multiply by 18/5. Remember: 72 km/hr = 20 m/s (this conversion appears frequently).
Worked ExampleSolve this step-by-step before moving on
1
Step 1
Distance covered = Length of train = 120m
2
Step 2
Time taken = 8 seconds
3
Step 3
Speed = Distance/Time = 120/8 = 15 m/s
4
Step 4
Convert to km/hr = 15 × 18/5 = 54 km/hr
Answer: 54 km/hr
Worked Example 2: Two trains of lengths 100m and 150m are running in opposite directions at speeds 40 km/hr and 50 km/hr respectively. In how much time will they cross each other?
Relative speed = 100/9 + 125/9 = 225/9 = 25 m/s (opposite direction, so add)
3
Step 3
Total distance = 100 + 150 = 250m
4
Step 4
Time = Distance/Speed = 250/25 = 10 seconds
Answer: 10 seconds
Advanced Shortcut - Platform Formula: Time to cross platform = (Train length + Platform length)/Speed. This direct formula saves calculation steps in exams.
Most Common Trap: Students forget to add platform/bridge length when train crosses them. They only consider train length, leading to wrong answers. Always read whether the train crosses a pole (only train length) or platform/bridge (train length + platform/bridge length).
Another frequent mistake is wrong unit conversion. Practice the 5/18 conversion thoroughly. Many students confuse when to multiply or divide.
Speed-Distance-Time Shortcut: If train crosses pole in time T1 and platform in time T2, then platform length = speed × (T2 - T1). This eliminates the need to calculate train length first.