The shortages have major implications for reliability: The company canceled at least one train on more than half of the weekdays in March, according to a review of the company’s public cancellation alerts. On four days in March, nine trains appear to have been canceled. This week, multiple rush-hour trains were canceled from Tuesday through Friday.

Keolis Commuter Services operated without the required number of locomotives for regular service through the vast majority of weekdays in March and April largely because of equipment failure and defects, according to newly released statistics that shed light on the delays that have plagued the commuter lines that carry tens of thousands of Greater Boston workers daily .


The problem has become so pronounced that Keolis employees will be working through the weekend to ensure there are enough locomotives available, according to MBTA spokesman Joe Pesaturo.

Pesaturo said Keolis crews “are making progress every day.” The operation began with five more locomotives on Friday morning than on Thursday morning, he said. The company was still five locomotives short of the 67 locomotives required by its contract, however.

“Work will continue nonstop throughout the weekend to ensure that even more locomotives are in service Monday morning and all of next week,” said Pesaturo. MBTA personnel will be on-site to continue to oversee the contractor’s progress, he said.

Keolis was able to provide the required number of locomotives for only four of 23 weekdays in March. For every April weekday so far, Keolis has been at least five locomotives short of the required 67, dipping to just 58 locomotives on Thursday, according to figures from the MBTA and Keolis.

Keolis has blamed defects in the MBTA’s newest locomotives, as well as unreliable older locomotives, for shortcomings in service. A Keolis official on Friday said that an older locomotive — which had a “last-minute equipment failure” — had bungled that morning’s commute on several lines.


“We made significant progress on locomotive maintenance over the past several days, including through last night, and were ready to operate full service this morning,” Keolis spokesman Tory Mazzola wrote in an e-mail Friday. “We appreciate the patience of the customers as we resolve this as quickly as possible.”

Since July, the MBTA has fined Keolis more than $204,000 for not having enough locomotives available for regular weekday service, according to the MBTA. About $44,000 of those penalties stemmed from March.

The contractor, which took over in 2014, has faced questions about whether it was equipped to run the operation with its $2.7 billion bid, which competitors criticized as too low. Others have questioned the MBTA’s newest locomotives, made by Idaho-based Motive Power Inc. with General Electric. Although Keolis Commuter Services is paid to operate and maintain the trains, the equipment is owned by the MBTA.

Jacquelyn Goddard, a spokeswoman for the Massachusetts Department of Transportation, said Friday that Governor Charlie Baker’s administration “will continue to hold the operator accountable for performance and expects existing mechanical issues to be addressed.”

Riders’ patience is running out — as is that of the board that oversees the MBTA, which had harsh words for the service in recent weeks. Some board members expressed disappointment in recent weeks about the paucity of available locomotives, as the agency had agreed last year to give the company at least $66 million over the life of its contract to invest in improving service, take on more trips, and become more aggressive with maintenance.


Part of that deal included additional fines that would be levied for every day the company failed to have 67 locomotives available in the morning. Of those 67, two are reserved as spares, to pick up the slack for breakdowns. Keolis officials say that around 63 locomotives can run a full schedule, though it increases the chance for delays.

The company fared much better with locomotive availability in February, but the MBTA still fined Keolis for locomotive shortages eight days that month.

The MBTA’s newest locomotives have had problems, and the MBTA has said that many of the older locomotives have not gone through all the recommended overhauls. Officials said on Monday that only 27 of 40 of the MBTA’s newest locomotives were in service, partly because of problems with an engine part that must now be replaced on all of the newest locomotives.

Don Wheaton, president of the union that represents Keolis’s conductors, also put blame on the aging locomotives, saying that many that are decades old must be refurbished.

“The chickens are coming home to roost,” he said. “How do you maintain a 40-year-old engine? They’re just getting old and worn out.”

But Keolis has also had trouble maintaining enough coaches because two crucial wheel-repairing machines had to be replaced, a process that takes up to six weeks.

That’s partly why riders have had to deal with overcrowded trains.


In March, Keolis Commuter Services was able to provide the required 362 coaches during only 17 of 23 weekdays in March, according to data from the MBTA.

Keolis declined to provide a breakdown of the number of train cancellations by week, but officials said they had canceled a total of 121 trains from Jan. 1 until Thursday afternoon, 61 of which were during peak hours.

The bulk of this year’s delays and cancellations have occurred during the rush-hour commutes since the beginning of March. Keolis officials provided statistics showing that the record since Jan. 1 has been much better. They say that since that date, 99.7 percent of all scheduled trains have run, including weekend and non-rush-hour trains.

Mary Z. Connaughton, a director at the Pioneer Institute, a fiscally conservative think tank, said riders have had enough. Connaughton, who rides the Worcester/Framingham line, said she frequently sees exasperated riders crammed into trains because they don’t have enough coaches.

Connaughton said she worries that Keolis may not have done “adequate due diligence” when assessing the condition of the MBTA’s trains during the bidding process, and that the MBTA may have to again revisit the contract.

“Ultimately, riders don’t care what the reasons are,” she said. “They need to get where they need to go in a timely way. If you’re taking your kid to a doctor’s appointment and your train is canceled, it has very significant rippling effects.”

Nicole Dungca can be reached at nicole.dungca@globe.com. Follow her on Twitter @ndungca.