T OFFICIALS SAY A NEW APPROACH to dealing with commuter rail delays improved performance dramatically on the Worcester Line, which in November had its best month in terms of on-time performance in almost three years. The high performance on the line continued into the first two weeks of December.

Dan Grabauskas, a consultant brought in the by the MBTA to oversee commuter rail, said the key to gaining the improvement was getting teams from the T and Keolis Commuter Services, the company running the trains, to work together in exploring the cause of delays and what can be done to eliminate or reduce them.

“It may sound pretty straightforward, but it was not happening that way,” Grabauskas told the T’s Fiscal and Management Control Board. He said an “unhealthy tension” existed between the two sides prior to them coming together.

The first job of the group was to identify where the problems were occurring. Grabauskas said the group identified more than 60 types of problems, lumped within broader categories such as locomotives, signals, heavy ridership, weather, and speed restrictions. In October, Grabauskas said 279 delays were identified across the system due to insufficient staffing and heavy ridership, with 28 percent of the delays occurring on the Worcester Line. According to the presentation, insufficient staffing accounted for 58 delays, which averaged seven minutes apiece.

Steve Poftak, a member of the control board, raised concerns about using heavy ridership as a cause of delays, saying Keolis should be prepared to cope with more passengers. Grabauskas agreed, saying he would look more closely at that category to see what was really causing the delays.

The next step for the T-Keolois group was eliminating or cutting down on the delays, starting with the Worcester Line, which over the last year has been the line with the second-highest ridership and the worst on-time performance. From October 2016 through October 2017, the Worcester Line’s on-time performance ranged from a low of 51 percent to a high of 92.5 percent, with an average of 77.8 percent. A train is considered on-time if it arrives within five minutes of its scheduled arrival time.

Grabauskas said the group identified a number of steps to address delays, including adding staffing on heavy ridership trains, eliminating recurring signal issues, and increasing track speeds. “There was no silver bullet,” he said, adding that one person was put in charge of the effort to provide some accountability.

The changes were put in place on October 23, and the results have been dramatic. Grabauskas said the month started off with on-time performances of 86 percent and 89 percent during the first two weeks. Keolis then rattled off four weeks of 90 percent or higher, something that hadn’t been done since January 2015.  The on-time performance during the week of December 11 was 97.6 percent.

Grabauskas said the Worcester Line has had 100 percent on-time performance during the morning peak 19 times since October 27. On five days, the line had 100 percent on-time performance all day long.

The T also added a ninth car to the Number 508 train, which departs Worcester at 6:57 a.m. and is scheduled to arrive at South Station at 8:20 a.m. Grabauskas said the Number 508 is the highest ridership train on the entire commuter rail network and 160 people were often left standing for a good chunk of the trip, Grabauskas said. By adding a ninth car, Grabauskas said, everyone got seats initially, but now he said traffic appears to be growing and passengers are again standing.

He said the added passenger car provided convenience, but the biggest draw is that the Number 508 was late only once in November. In October, it was late 20 times, he said.

“As a Worcester Line rider, thank you. And don’t slip backward,” said Transportation Secretary Stephanie Pollack.

Grabauskas said the next line the T-Keolis group plans to focus on will be the Haverhill Line.

David Scorey, general manager of Keolis, said October commuter rail revenues were up 3.8 percent over the same month a year ago. “We can’t say it’s a trend,” Scorey said, but he was hopeful improved on-time reliability combined with fare vigilance and better marketing would keep revenues increasing.

Keolis has been checking passengers at North Station during the evening peak to make sure they have tickets before boarding trains. He said about 500,000 passengers were checked in October and November, and between 180 and 200 lacked proper tickets before boarding. He said the inspections will expand to Back Bay Station early next year, at the same time conductors will begin using on-board devices for collecting fares and Keolis rolls out a new marketing campaign to attract more riders.