For a second straight day, Boston commuters contended with congested roads and sluggish trains in the snowbound city on Wednesday — conditions compounded by the return of school buses and the presence of thousands of fans celebrating the New England Patriots’ Super Bowl victory.
Commuter rail trains reported delays throughout the day, evidence of mechanical problems and increased demand from revelers bound for the Patriots parade. Some afternoon and evening trains, including those on the Haverhill, Framingham/Worcester, and Lowell lines were canceled, according to the commuter rail’s Twitter account.
On Boston’s streets, 1,254 of approximately 1,580 morning buses carrying Boston public school students ran late, according to figures provided by Denise Snyder, a school district spokeswoman. Buses are expected to run earlier Thursday morning to get students to class on time, the School Department said.
Traffic was particularly clogged on Dorchester Avenue, beset with episodes of gridlock.
“Dorchester Avenue was tough today — I went down there,’’ Mayor Martin J. Walsh said. “A lot of Dorchester was tough.”
Brockton resident Joanne Lavey said her 11:57 a.m. train from South Station was delayed because of the throngs in the city for the parade. She said she needed to get home to a “very sick” 13-year-old daughter.
“They really shouldn’t hold up people to go home because of this,” said Lavey, as televisions in a South Station bar carried live coverage of the parade. “I pay for a monthly pass and I pay a lot of money; and for them to have me sitting here, I think it’s pretty sad.”
Mike Fortin and roommate Ryan McLane said the commuter train they took from TF Green Airport in Warwick, R.I., ran an hour late. When they arrived at noon, they figured they had missed the parade. At Park Street Station, however, they learned they had arrived in time.
“It was like this jump from depression to extreme, extreme joy,” Fortin said.
Keolis, the company that runs commuter rail service for the MBTA, said morning delays were “largely caused by huge crowds” boarding trains systemwide. Spokesman Mac Daniel estimated commuter trains carried 10,000 to 15,000 extra passengers.
“We ran extra trains to pick up passengers that could not get on crowded trains, and despite the delays, which happen when you have this kind of demand, things went well,” he said in an e-mail.
Subway service, which was hobbled Tuesday by an unprecedented level of breakdowns, experienced “significant improvement” Wednesday, but still had not returned to regular levels, said Beverly Scott, general manager of the MBTA.
“We have just tried to be very honest about what our capacity is, which we are improving, but we are not normal,” she said.
The number of subway cars in service increased on all subway lines, including the Red Line, which had 120 cars working Wednesday, compared to 84 the day before.
Crews worked Tuesday night into Wednesday morning to clear snow and ice from critical track components, resulting in fewer delays from signal or switch problems, MBTA spokesman Joe Pesaturo said.
“Despite the winter beating it took over the course of a week, the aging transit system performed well today,” Pesaturo said.
Some commuters, however, described long journeys on delayed trains and buses.
Donna Bayne was more than two hours into her commute to Canton on Wednesday morning but had made it only as far as Dorchester’s Ashmont Station.
“We can put a man on the moon but we can’t figure out how to insulate signals when they freeze up in the cold weather,” said Bayne, who lives in Revere.
For some, fraught travel did little to dampen the day. Shrewsbury resident Virginia Ogozalek said her train from Grafton to Boston was slow but “wonderful” as she traveled to the Patriots parade.
“I was so happy the train was there,” Ogozalek said. “It took me to see Tom Brady.”
Laura Crimaldi can be reached at email@example.com. Martin Finucane, Andrew Ryan, Peter Schworm, and James Vaznis of the Globe staff, and Globe correspondent Aneri Pattani contributed to this report.