Metro Railway has been saddled with five glitch-prone air-conditioned rakes that are more often in the maintenance shed than on the tracks. Worse, eight more are to join the fleet by next March without a dry run to detect possible problems.

The first of the AC rakes, all built at the Integral Coach Factory (ICF) in Perambur, near Chennai, had joined the ageing Metro fleet in September last year and four more have since arrived. The problem is, none of these rakes has yet been on full-time duty because of breakdowns every few rides.

“All the AC rakes we have received so far have given us problems. The Perambur unit does not have the infrastructure to do a dry run of coaches fresh off the assembly line, so there is no guarantee that the rest of the lot will be glitch-free,” said a senior official of Metro Railway.

The railway ministry has spent nearly Rs 500 crore on the 13 AC rakes.

An ICF official confirmed that the Perambur facility lacked facilities for a dry run of the new Metro rakes. “We don’t have a third rail here (the one that supplies power to the rakes). We are modifying the rakes that have yet to be delivered on the basis of feedback from Calcutta,” he said.

Metro Railway is planning to send a proposal to the Railway Board to set up a dry run facility at the ICF factory. “Even a two-kilometre stretch will solve the problem,” an official said.

Three of the rakes in operation were withdrawn from the Metro fleet on October 12 and have since been undergoing extensive repairs at the Noapara maintenance shed. A snag forced out the fourth during its first commercial run before Puja.

The only one that was doing two runs a day on an average developed a snag last Friday and has since been out of action.

“The train had reached New Garia station and was changing tracks when the motorman discovered that the brakes weren’t working properly,” a maintenance engineer said.

The first of the two rakes that had joined the fleet on Mahalaya last year has had the roughest ride with doors, brakes and other systems functioning erratically. The rake is undergoing extensive modifications.

Engineers of Metro Railway and the Research Standards and Design Organisation are making the technical changes, sources said.