Due to power problems caused by the loss of a Con Edison feeder cable, Metro-North service on the New Haven Line will be "extremely limited," according to its website, new.mta.info.

Service out of Grand Central Terminal is being offered at 10 past every hour via diesel-powered trains. Those trains will make stops from Grand Central Terminal to Stamford. Electric-powered trains will take riders between Stamford and New Haven, with those trains departing Stamford at 14 past the hour.

"The service plan can accommodate 10% of the regular ridership on the New Haven Line," the website said.

In a news conference, Gov. Dannel Malloy estimated the repair of the feeder cable could take two to three weeks.

Con Edison reported that the 138-kilovolt feeder cable failed at about 5:22 a.m. The failure nearly brought all train traffic into New York’s Grand Central Station to a halt.

The electrical issue will force Metro-North to operate diesel-powered trains between Stamford and New York’s Grand Central Terminal. Those trains will only run once per hour while Con Edison crews work on making repairs, Mr. Malloy said.

Using only diesel trains to get into New York will allow Metro-North to carry only about 30 percent of its daily traffic, Mr. Malloy said.

A Con Ed representative said Wednesday that another feeder normally providing service to the New Haven line was out on scheduled repairs to accommodate Metro-North upgrades on their equipment.

Mr. Malloy cautioned commuters that the repairs could take about three weeks to fix and that the change will have commuters dealing with more crowded trains. While he hopes the problem can be rectified soon, Mr. Malloy told commuters to plan for lengthy delays.

“I think people need to now assume this is a long-term problem,” Mr. Malloy said in a Wednesday afternoon press briefing with reporters.

Monthly New Haven line customer tickets will be honored along the Harlem line, though Mr. Malloy encouraged commuters to make other plans, including telecommuting or carpooling to cut down on the traffic.

Aaron Donovan, a spokesman for the Metropolitan Transportation Authority, said that while New Haven line users can board on the Harlem line, commuter parking lots there are already crowded regularly. Donovan said it is “strongly suggested” that New Haven line commuters get dropped off at those Harlem line stops rather than try to park in New York.

Emily Moser, a commuter who runs the blog Iridetheharlemline.com, said that parking would be a concern if Connecticut riders decided to park at Harlem line stations. “Many stations on the Harlem Line have large lots with daily parking, but it’s of course first come first served. Getting there early would be a very good suggestion. The further south you get, the harder it might be to find parking,” Moser said.

The best spots to park, Ms. Moser said, would be the Southeast and Goldens Bridge stations, which have large lots and plenty of parking.