Subway service on the A, B, C, and D lines in Upper Manhattan came to a screeching halt Monday after weekend track work exposed cracks underneath the trackbed, according to the MTA.

Emergency repairs are underway at 81st Street and Central Park West. The problem was discovered there over the weekend during planned track work.

As of early Monday afternoon, there’s no downtown local service from 125 St to 59 St-Columbus Circle. Downtown B and C service are running express, skipping all local stops in the downtown direction.

The MTA says there won’t be any B trains in the Bronx or Upper Manhattan through at least the day Monday.

The agency is working to implement a temporary fix, with permanent repairs scheduled for a later date. They say crews are working “around the clock” to get downtown service up and running as quickly as possible.

In the meantime, uptown A, B, C, and D service is running with delays. B and C trains are making all uptown local stops. Get the latest from the MTA here.