About 130,000 people a day use the commuter rail, and transit specialists have long said ridership would jump sharply if the service were reliable.

The major repairs are the latest roadblock in a years-long effort by the MBTA to acquire a fleet of new locomotives to revitalize its rail service, which has had chronic difficulty with on-time performance.

The 40 new commuter rail locomotives delivered to the MBTA late last year at a cost of $222 million have all been sidelined to have their traction motor bearings replaced after the manufacturer discovered last summer that at least some of the bearings are faulty.


So far, just eight of the locomotives have been repaired. The work will delay the debut of the full complement of locomotives until late this year.

The MBTA knew about the defective bearings last August, but chose to make no public disclosure until the Globe learned about the problems last week.

The decision to remain silent followed criticism of the MBTA for another troubled acquisition. The transit system spent $190 million for 75 new commuter rail passenger cars, which were delivered 30 months late by the South Korean manufacturer Hyundai Rotem and so trouble-prone many of their parts have had to be replaced.

Joe Pesaturo, an MBTA spokesman, said last week that the eight locomotives that have been repaired are in service.

But according to records reviewed by the Globe on Monday, just four were in service Friday and Monday. The other four had been taken out of service for maintenance problems unrelated to the bearings, according to the records.

Last November, when the Globe asked about 11 of the locomotives that had just been delivered, Pesaturo said they were “undergoing testing.’’

Asked last Friday why he failed to disclose that the traction motor bearings needed replacement, he said: “The traction motor bearing replacement had not yet begun on the 11 locomotives in question.’’


Also in November, the MBTA fined the rail system’s operator, Keolis, more than $400,000 for falling short of on-time performance standards. Yet commuter rail analysts say those benchmarks are not attainable without the new locomotives whose defects the MBTA decided not to disclose.

Technically, all 40 of the locomotives were delivered by the end of 2014 by the principal manufacturer, Motive Power Inc. of Boise, Idaho. But 20 were sent directly to Altoona, Pa., to have the traction motor bearings replaced. The rest are having the work done at a Providence and Worcester Railroad maintenance facility in Worcester.

The delays matter to daily commuters, and to Keolis, the French railway company that began operating the rail system in July and has an eight-year contract with the MBTA. The 40 locomotives are supposed to replace unreliable locomotives, many of which have been in service since the late 1970s.

For commuters, it has been a very long wait. After a false start that began in 2008, the MBTA contracted with Motive Power in 2010 for the first 20 of the 40 locomotives. The delivery date was supposed to be 2013. After the order was expanded, the delivery date was moved back a year. When Keolis took over the service, it anticipated having the new equipment in service by the end of 2014. On Friday, Pesaturo said all of the locomotives are now expected to be in service by late this year.


When the MBTA fined Keolis for not meeting on-time performance goals, Eric Asselin, the executive vice president of Keolis North America, attributed the anemic performance to the aged and unreliable locomotive fleet. He said the new equipment will be needed to resolve on-time issues.

Asselin’s complaint is borne out by the MBTA’s own statistics. The transit authority sets a goal for its commuter rail locomotives to travel an average of 10,200 miles between mechanical failures. In October, the month for which the fines were levied, that number nose-dived to 3,193 miles, less than half what it was the previous month.

Half of all local commuter rail delays are caused by substandard locomotives, according to transit officials.

Mac Daniel, a spokesman for Keolis, declined on Monday to answer questions about the recent impact of the delayed deliveries.

The new locomotives are diesel-electric hybrids. Each has a 4,600-horsepower diesel engine that powers four electric traction motors that drive the wheels. The engines and motors were manufactured by General Electric.

The high-precision ball bearings reduce friction and make possible the smooth rotation of the axles that are driven by the electric motors.

In e-mails, Pesaturo initially said the locomotives did not require post-delivery modifications to make them operable. He said they only needed to have the bearings replaced “as a precaution to ensure that the traction motor bearings last for their design life.’’

The bearings, he said, were not improperly installed, but some were damaged when they were shipped from Pennsylvania to Idaho in a way that could diminish the life of the bearings. They are being replaced at no cost to the transit authority, according to Pesaturo.


Pesaturo, who refused to talk to a Globe reporter, said in one of several e-mail responses that the MBTA saw no need to disclose the defective bearings since the repairs are being done at no cost to the MBTA, the locomotives were manufactured on schedule, and they were “operational” when they left Idaho.

Jonathan Klein, a former chief mechanical officer for Amtrak who has long experience in contracts for new commuter rail equipment, said he is heartened that Motive Power and GE discovered the problem and are replacing the bearings.

Even so, Klein said, “something is fundamentally screwed-up with a contract to pay nearly a quarter billion dollars for locomotives that immediately go into storage for repairs.’’

Klein said the transit system has a “dismal history” with its purchases of new commuter rail and rapid transit equipment.

Moreover, he said, “keeping quiet about this and pretending that nothing major happened is questionable contract management when your new fleet won’t operate. You owe it to riders and crews to let them know there is a major problem and you are working on it.’’

The bearings aside, one mechanical specialist raised concerns about the reliability of the locomotives.

Joseph A. English, a long-time foreman who is also the union representative for commuter rail mechanical supervisors at the MBTA and at Amtrak, said there have been ongoing service issues with the new locomotives. Many of the problems, he said, stem from failures in the system’s software that impede communications with the passenger cars.


Long-term, English said, the mechanics who work on the locomotives fear “there will be ongoing reliability issues.’’

Walter Robinson can be reached at walter.robinson@globe.com.