MBTA officials will unveil the first of 40 new environmentally friendly commuter rail locomotives at North Station on Wednesday, transportation officials said.
Each new locomotive will be tested and put into service on the MBTA’s 12 commuter rail lines as they arrive over the summer.
That will allow older equipment, some of which has been in use for 40 years, to be taken out of service.
The first engine will begin its run Wednesday morning at North Station, and will traverse the Haverhill Line.
Idaho company MotivePower, Inc. was awarded a $222 million contract in August 2010 to design and build the diesel-electric locomotives at its headquarters in Boise.
The new locomotives will be more reliable and will have better air systems than the engines they are replacing, said Kelly Smith, spokeswoman for the Massachusetts Bay Transportation Authority.
The new locomotives are compliant with Environmental Protection Agency standards and are more fuel efficient, officials say.
The MBTA expects up to a 6 percent increase in fuel efficiency, resulting in about 10,000 gallons of fuel saved per locomotive per year, or the equivalent of $1 million in annual savings, officials said.Jacqueline Tempera can be reached at jacqueline.tempera
@globe.com. Follow her on Twitter @jacktemp.