Two trains of equal length are running on parallel lines in the same direction at 46 km/hr and 36 km/hr. The faster train passes the slower train in 36 seconds. The length of each train is:

Given Data

• Two trains of equal length run in the same direction
• Speeds = 46 km/hr and 36 km/hr
• Time for the faster to pass the slower = 36 s
• Required: length of each train

Step 1: Use relative speed (same direction ⇒ difference)v_rel = 46 − 36 = 10 km/hrConvert to m/s: 10 × (5/18) = 50/18 ≈ 2.7778 m/s

Step 2: Crossing distanceFor one train to completely pass the other, distance = sum of lengths = L + L = 2LTime t = 36 s = distance ÷ speed = (2L) ÷ v_rel2L = v_rel × t = (50/18) × 36 = 100 m ⇒ L = 50 m

Checks & Common Pitfalls

• Same direction uses the difference of speeds, not the sum.
• Crossing another train requires the sum of their lengths.
• Keep units consistent (convert km/hr to m/s).

Final AnswerEach train's length is 50 m.