THE MBTA IS PLANNING to spend close to $60 million to nearly double the number of new or overhauled commuter rail locomotives in its fleet by the end of next year.

T officials said they have 44 new or overhauled locomotives currently, and plan to spend $57.1 million to add another 39. That would still leave the T seven short of its goal of 90 new or overhauled locomotives, but officials said they are looking at other options, including the lease of additional vehicles.

Keolis Commuter Services is responsible for operating and maintaining the T’s commuter rail locomotives and coaches, but the MBTA is responsible for the vehicles themselves. T officials said on Monday that 46 locomotives are in tough shape, most of them requiring major overhauls to extend their useful life.

Keolis has had difficulty meeting its performance targets in recent months because it has been unable to keep 67 locomotives ready for daily service. While the number of available locomotives has increased to more than 67 in recent weeks, MBTA officials said a large number of vehicles still need to be overhauled to make sure they last until a procurement for new vehicles can be completed. Locomotive procurements typically take six years, officials said.

Three of the planned overhaul programs would be done by Keolis, at a price of $1.2 million per locomotive.  Keolis is already under contract to overhaul 10 locomotives and a contract for another eight is being considered.

The MBTA is also putting out to bid the overhaul of another 16 locomotives at an estimated cost of $37 million. Another five locomotives are being fixed at a cost of $500,000, but officials said those repairs would not extend the life of the vehicles.  The T also plans to purchase 15 new locomotive engines at a cost of $4.5 million, or $300,000 per engine.

In a presentation to the MBTA’s Fiscal and Management Control Board, T officials said they expected to have 67 new or overhauled locomotives available for daily service by May or June of next year.