If you’re taking a commuter train west of Boston, which track has the greatest chance of making you late for work?
It’s the Fitchburg/South Acton Line — although the odds are still good that you’ll arrive on time.
Its trains stayed on schedule 90.26 percent of the time last year, which falls short of the operator’s contractual goal of a 95 percent on-time rate. This year, the Fitchburg/South Acton Line has done better, with an on-time rate of 93.8 percent through October, according to the Massachusetts Bay Commuter Railroad Co., which runs the system for the Massachusetts Bay Transportation Authority.
While train breakdowns or big storms, like the snow that hit the area last week, can make for a day of frustration for any commuter, the region’s rail lines got generally good grades from riders in recent interviews.
Most people interviewed during two days of rides across several commuter lines this month were either happy with their line or stoic about the occasional delay. But some were frustrated and angry about the late trains because their bosses are not very understanding when they show up late.
The overall on-time performance for all of the system’s rail lines was above 95 percent last year and so far this year, according to Mass. Bay Commuter Rail figures.
The company is facing competition from Keolis, an international transit giant, for the next contract to run the MBTA’s system. A vote on the contract, which will take effect on July 1, is expected early in the new year.
MBCR runs nearly 500 trains a day and carries more than 35 million riders annually for the T.
On-time performance is “critical, absolutely critical” to commuter rail passengers, said Paul Regan, executive director of the MBTA Advisory Board, which is an independent entity comprising representatives from the 175 cities and towns served by the transportation authority.
Many delays are the result of dispatch woes caused by berth overcrowding at North and South stations, old signal equipment, and the age of the trains themselves, he said.
MBCR’s official on-time record of 95 percent comes with a large asterisk. Delays that are caused by forces outside MBCR’s control — medical or police emergencies, snowstorms, slow freight trains that have priority — are not counted against it.
Breakdowns of passenger cars or locomotives, and problems with infrastructure such as signals and switches are the responsibility of MBCR, and the company pays a fine for late trains if the cause is considered to be under its control.
Using delays from any cause to calculate MBCR’s on-time record drops its performance by about 4 percentage points, according to a Globe analysis.
There are many reasons for delays. A fire Monday afternoon at a rail maintenance yard in Somerville meant the cancellation of nine North Station trains, including an inbound and outbound train on the Fitchburg/South Acton Line.
But Regan, speaking in general, said riders don’t care whose fault it is. “Most people can’t roll into work 20 minutes late routinely and not have repercussions,” he noted.
Stephanie Pollack, associate director at Northeastern University’s Dukakis Center for Urban and Regional Policy, said taking the train often has huge advantages over travel by car.
According to the MBTA’s website, a monthly pass runs between $70 and $314, depending on the starting point, which can be a good deal when compared with the cost of gas and upkeep of a car, parking in the city, and tolls.
Pollack pointed out, however, that the contract with MBCR offers no incentives for growing ridership. Commuters notice when the air conditioning or heat doesn’t work, or if the cars are dirty, she said, highlighting problems that could discourage people from taking the train.
“If ridership is growing, you are providing a service that people are willing to pay for,’’ she said. “If it’s declining, that’s a sign of trouble.”
And ridership has been dropping. The average number of daily commuters fell 12.5 percent between 2003 and 2013, which runs against the national trend of rising usage.
But John Hogan, the chief transportation officer for Mass. Bay Commuter Rail, said ridership during peak hours was up 6 percent this fall compared with a year ago.
The company is working hard to improve its on-time performance, he said. New locomotives and passenger cars will make a real difference, for the simple reason that they are less prone to break down, Hogan said. The average age of the T’s locomotives is 40 years old.
Response time to problems has also improved, he said. If a train breaks down, a replacement typically leaves within five minutes, the MBCR says.
A delay for a breakdown or a medical emergency can have ripple effects through a line, said Scott Farmelant, a spokesman. A fatality delays trains on average by 40 minutes, with the trains directly affected being late by more than an hour.
Several commuters complained that the text alert system for late or canceled trains was poor. Farmelant noted the system has been changed to make it more responsive. The information is posted on signs at stations and the company’s Twitter feed, @MBCR_info .
Improvements are coming to the Fitchburg line, the oldest line in terms of infrastructure and the longest, according to Hogan and Farmelant, that should improve performance.
Ongoing work, to be mostly completed by the end of 2015, includes replacing or repairing eight bridges, upgrading signals, and “double tracking” an 11-mile stretch of single tracks between South Acton and Ayer. Also, the stations in Littleton and South Acton will be upgraded, and a Wachusett extension will be added.
“There will be quicker service, more service, and maybe more express trains,” said Hogan. “There will be a little pain for existing customers until we get there.”
On-time performance is always on riders’ minds.
Deborah Neisel-Sanders has been taking the train from Lincoln for almost 10 years but isn’t all that happy with its performance through the years. Nearly a decade ago, she lost her old job as an administrative assistant because the train’s on-time record was erratic.
“It’s one of the big challenges of my life,” said the Lincoln resident. The way she sees it, people at higher-level jobs are less affected by delays because their work schedules are more flexible, and they can work on the train or at home.
Waiting at the open-air stop is no joy trip, either. “If I have to wait more than 10 minutes, I’m a popsicle,” she said.
Margie Brown, who works for the National Park Service, usually in Charlestown, said the train is much better than driving. It’s faster and better for the environment, she noted. “There’s so much congestion on the roads,” she said.
Peg Hedstrom, of Concord, takes a stoic attitude toward the delays. “I’m so used to it,” said the program administrator at Harvard College Observatory.
“It’s no worse than the buses, and still more reliable than getting stuck in traffic,” she said. “No amount of sitting here reading is worse than sitting in traffic.”Matt Carroll can be reached at email@example.com. Follow him on Twitter @globemattc.