Heavily oil stained, 5 feet 6 inch gauge 3831 built in the 1950s as an ALCO DL500 nears Kolpur with the "Chiltan Express", 1000 Lahore to Quetta. Kolpur is the top of the tortuous Bolan Pass much of which is 1 in 25 (4%) grade. 2 sister locos were pushing at the rear of the train.