"The passenger train's engine had broken down after which we sent a relief engine. The relief engine was moving at a slow speed of 10 kmph and it bumped into the stationary Nangal Dam-Ambala passenger train near the Industrial Area here," Northern Railways (Ambala) Divisional Railway Manager, P K Sanghi said.
While the DRM said only two to three persons sustained minor injuries, eyewitness accounts claimed that five or more were injured.
The injured had been admitted to GMCH hospital in Sector 32 here, Sanghi said.
Due to the accident, the movement of Jan Shatabdi express train was affected.
"We are inspecting the spot. Efforts are on to pull back the train to Mohali side," he added.
The passenger train runs between Ambala in Haryana and Nangal in Punjab and mostly covers areas falling in Punjab including Mohali, Ropar and Anandpur Sahib.