And with construction continuing along Interstate 95 in Delaware, many highway travelers are likely to face delays this week, too.
"We're making the same recommendations as we did for Thanksgiving: look for alternative routes, plan for nonpeak times at night or early mornings," said Bob King, a spokesman for the Delaware Transportation department. He suggested that drivers consider taking the Bay Bridge as an alternative to I-95, depending on their final destination.
Monday morning, a southbound MARC train on the Penn Line ran into mechanical problems, along with downed overhead electrical wires, according to Maryland Transit Administration spokesman Terry Owens. That caused delays to both north- and southbound trains, he said.
"Somehow a train got tangled up in the wires at a switch," said Christina Leeds, an Amtrak spokeswoman.
MTA officials turned around train 417 at West Baltimore, and it departed at 8:10 a.m., Owens said. The first train to leave Penn Station departed at 8:13 a.m., he added.
Meanwhile, Amtrak commuters at Penn Station were warned to expect delays of up to 20 minutes in departure times Monday, as the train line worked to clear up congestion from a power outage.
The 10-minute outage on two tracks affected three Amtrak trains. Power was restored at 8:03 a.m., and "some minor residual delays" were expected, Leeds said.
Amtrak schedules additional trains and adds cars to existing trains for the Thanksgiving travel period, but around Christmas, seats are only added as needed, said spokesman Steve Kulm. So far, the heaviest days would seem to be Wednesday and Thursday, he said, and travel levels off for the rest of the time.
He warned that passengers may see increased security in stations and on trains.
Anyone headed north on I-95 this week should expect the same construction delays that were seen at the Newark toll plaza in November, said Bob King, a spokesman for Delaware's transportation department.
The turnpike toll area has been reduced temporarily from nine lanes to six as part of a project to address the frequent backups that occur there.
After major delays were reported on the Wednesday before Thanksgiving, Delaware suspended toll charges from 3 p.m. to 11 p.m. to expedite travel. But there has been no discussion of doing that again, King said.
Charlie Gischlar, a spokesman for Maryland's State Highway Administration, said drivers should check for traffic alerts at roads.maryland.gov before they leave. "Before you go, log on," he said.
Any planned lane construction will be suspended throughout Maryland starting Wednesday to give highways more capacity, and the suspensions will resume again around Dec. 29. There hasn't been much scheduled, however.
"We can't do much because it's cold outside," Gischlar said. "There won't be a lot of roadwork going on other than emergency roadwork in the next two weeks."
If conditions indicate that a white Christmas is a possibility, SHA plans to pretreat interstates with either a salt brine or, in Frederick or Howard, a mix of brine and sugar beet molasses. But crews can only pretreat when the forecast calls for snow, not rain, because the liquid would just wash away, Gischlar said.
The film must hit the roadway and have time to dry, he said. "It buys a little time that way," he said. "It keeps the initial bonding of snow and ice from forming."
Holiday travel woes extended across the Atlantic to London, where transplanted Baltimoreans Jon Cylus and Olivia Nuccio say their flights home were canceled after a weekend snowstorm.
The couple, who moved to London six months ago, said they were baffled by the widespread travel disruptions in England because it only snowed briefly, if intensely, on Saturday. Nuccio, 28, who's studying at the London School of Hygiene and Tropical Medicine, said her Sunday flight out of Heathrow was canceled. Cylus, 26, who works for the World Health Organization and attends the London School of Economics, wasn't scheduled to fly out until Tuesday, but his flight also was canceled.
Nuccio tried to rebook flights via computer and phone, but couldn't get through to British Airways. So she journeyed an hour from their home to Heathrow, where she saw "hundreds, if not thousands" of people camped out waiting to catch delayed flights.
Nuccio now plans to leave Friday. Cylus is scheduled to fly Saturday night — though he's nervous that snowy weather in the Baltimore area by week's end might throw off his travel plans yet again.
"We're hoping to be home at least for New Year's," he said.
Jonathan Dean, the BWI Marshall Airport spokesman, said the airport, which has set monthly growth records since July, expects to be busy over the next two weeks. Given the potential for snow, passengers might want to consider parking their cars in one of the airport garages rather than in a long-term lot to make travel easier, he said.
Baltimore Sun reporters Yeganeh June Torbati and Timothy B. Wheeler contributed to this article.