Relative speed of the train = (40 - 22) km/hr = 18 km/hr
Relative speed of the train in m/sec = 18 x (5/18) = 5 m/sec.
Let the length of 2nd train be L meters.
Then, (125 + L) / 5 = 60 sec.
⇒ 125 + L = 300
⇒ L = 175
∴ Length of second train = 175 meters