MANHATTAN — It's going to be a madhouse.
Transit officials canceled dozens of trains, re-routed existing commutes and warned of massive delays after a morning derailment injured two people at Penn Station.
The MTA canceled 29 evening rush-hour trains out of Penn Station to let NJ Transit and Amtrak take over tracks 13-16, which they normally share with the Long Island Rail Road, officials said.
The changes come after an Amtrak train leaving Penn Station derailed and sideswiped a NJ Transit train as it pulled into the hub, officials said.
NJ transit suspended its service immediately after the crash.
Trains in and out of the station were disrupted in the immediate aftermath, but officials expected more to extend into the evening rush.
Here's what officials say commuters should expect, train by train:
► NJ Transit — There was limited outbound service from Penn Station starting at 4 p.m.
MidTown Direct trains continued to operate in and out of the Hoboken Terminal.
Cross honoring was also in effect for the evening commute.
Cross honoring will remain in effect with NJT bus, private bus, NY Waterway & PATH at Newark, Hoboken & NY 33rd— NJ TRANSIT (@NJTRANSIT) March 24, 2017
► Amtrak — Service in and out of Penn Station was delayed as their officials investigated the derailment, they said.
Keystone service will run in and out of Newark where passengers can then transfer to Northeast Regional trains, which will go into New York, Amtrak officials said. PATH trains will honor Keystone ticketed passengers, officials said.
Empire service will transfer to Metro-North, which will go in and out of Grand Central Terminal, officials said.
► LIRR — Officials said that commuters should expect evening rush cancellations and delays as their trains will only run on four tracks in and out of Penn Station at less than 50 percent of normal capacity. Officials canceled 29 trains between 4 p.m. and 8 p.m., including on the Babylon, Far Rockaway, Long Beach, Hempstead, Montauk, Port Washington and Port Jefferson branches, among others.
Westbound Port Washington Branch trains will end at Woodside, where riders can to transfer to the 7 to Manhattan. There will be no westbound service between Jamaica and Penn Station on other branches.
New York City Transit will cross-honor LIRR tickets at Woodside and Jamaica. Riders should use Atlantic Terminal, officials said.
The MTA will cross-honor LIRR tickets at Union Turnpike-Kew Gardens, Forest Hills-71st Avenue, 61st Street-Woodside, Hunters Pointe Avenue, Flushing-Main Street and at the Barclays Center.
► PATH — PATH trains should be running normally and will cross honor NJ Transit and Amtrak fairs.