Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.

Given Data

• Each train length = 500 m
• Speeds = 45 km/hr and 30 km/hr
• Opposite directions
• Required: time for the slower train to pass the driver (a point) of the faster train

Step 1: Relative speedv_rel = 45 + 30 = 75 km/hr = 75 × (5/18) = 20.8333 m/s

Step 2: Distance for passing a pointDistance = length of slower train = 500 mt = 500 ÷ 20.8333 = 24 s

Checks & Common Pitfalls

• Passing a point on another train uses only your train's length.
• Opposite directions ⇒ add speeds.

Final AnswerRequired time is 24 s.