India, June 28 -- India's first hydrogen-powered train ran a fresh set of trials between New Delhi and Jind on Friday, with engineers tracking emergency braking distance and oscillation as the project moves closer to commercial service.

The train touched a top speed of 120kmph on the Jind-Sonipat section during testing, though its operational speed will be set at 75kmph. An earlier round of trials had already been completed between Sonipat and Jind.

The Railway Board had cleared the introduction of the ten-coach trainset in a May 22 letter. The railways ministry's announcement of the approval followed five days later, on May 27, but it is yet to announce a date for starting passenger services.

Here's what is known about the project so ...