A technical snag in a diesel locomotive on the world heritage Kalka-Shimla route disrupted rail service for close to two-and-a-half hours on Friday.
Railway sources said the engine developed a problem near Solan town, 45 km from here, around 3 p.m. when the train was on way to Shimla from Kalka in Haryana.
In September, a chartered special toy train carrying a group of 37 foreigners derailed on the Kalka-Shimla route, killing two Britons.