A commuter rail coach detached from its train set Monday morning, causing widespread delays on all routes in and out of South Station.

In an event that Keolis officials say was not weather-related, an outbound train "experienced a mechanical issue leaving South Station that caused a coach car to become unattached from the train" at about 7:05 a.m., said Keolis spokesman Justin Thompson. Keolis operates the MBTA's commuter rail system.

"The train's safety features were working correctly and the train came to a complete stop," Thompson said, noting the train was headed for Foxborough. "There were 10 passengers onboard, who were transferred to another train."

There were no injuries and the train set was moving at less than 15 miles per hour when the incident occurred just outside the train terminal, where several routes converge, Thompson said.

At 7:35 a.m., the MBTA issued an email alert to customers that "terminal congestion caused by a disabled train near South Station's entrance" was creating delays of up to 20 minutes inbound and outbound on the Framingham/Worcester, Needham, Franklin, Fairmount, Providence/Stoughton, Middleborough/Lakeville, Kingston/Plymouth, and Greenbush lines.

The problem surfaced during the rush-hour commute only hours after Keolis touted its preparations for the state's first significant snowstorm of the season. The storm is dumping snow and rain unevenly across the state, with precipitation overnight Sunday followed by a respite before another round of rain and snow Monday night.

Keolis on Sunday reported that the company and the T had invested more than $100 million since 2014 to make operations more resilient during wintertime. In advance of the storm, Keolis said more than 350 workers would be deployed across the rail system to shovel, sand and salt passenger areas and to respond to incidents that occur during the storm, with crews pre-positioned at switch and signal infrastructure "to help ensure normal operations."

"Our goal is to minimize the storm’s impact on service to ensure passengers who need to travel can use Commuter Rail as an alternative to driving in these conditions," David Scorey, Keolis CEO and general manager, said in a statement on Sunday.

In mid-November, Gov. Charlie Baker, whose administration is in the midst of a years-long effort to improve MBTA service, predicted passengers would be able to count on the T this winter for reliable service.

"I think people will have a winter where the T will be there when it needs to be," Baker said on WCVB's "On the Record."

Baker also urged the Legislature to act on his $18 billion long-term borrowing bill for transportation. The House and Senate are in the midst of a multi-week break from formal sessions, recessing in mid-November without taking action on the bond bill or separate legislation aimed at raising revenue for transportation.

Thompson reported just before 9 a.m. Monday that trains operating in and out of North Station were operating on or close to schedule.