A train derailment on the Northeast Corridor late Wednesday is expected to continue causing delays for commuters into Friday.

SEPTA will run limited service on the Wilmington/Newark Line on Friday, but far fewer trains than would be needed to handle typical weekday commuter traffic. Service on that line will end at 9 p.m. The agency advised riders to consult a special timetable it will post online as selected trains will operate at different times than regularly scheduled.

"SEPTA is working to design a schedule that will provide as much service as possible, but there will not be enough trains to accommodate normal weekday ridership levels," a statement from the transit agency said.

Two hopper cars on a Norfolk Southern freight train derailed in Delaware County about 11:30 p.m. Wednesday. The 88-car freight train was carrying crushed stone from Birdsboro, Pa., and Edgemoor, Del., and was pulled by two locomotives, a railroad spokesman said.

The derailed cars were the last two on the train. They tipped over and spilled their loads between SEPTA's Eddystone and Crum Lynne stations, officials said.

The incident halted service on SEPTA's Wilmington/Newark Line and seriously disrupted service on Amtrak between Washington and Philadelphia. No one was injured.

After suspending service around 5 a.m. Thursday, Amtrak announced three hours later that service was resuming but with significant delays because of a reduced number of tracks through the derailment area. It later announced a series of cancellations.

SEPTA said service on its southernmost Regional Rail line would remain suspended overnight Thursday after about a mile of track was reported damaged in the derailment.

There are four parallel tracks in the area of the derailment, rail officials said, and as of Thursday morning, two of them, tracks one and four, were open to traffic. The derailment happened on track three, Amtrak officials said. The Federal Railroad Administration is investigating and inspectors were at the scene Thursday morning, an FRA spokesman said.

He had no information on the cause of the derailment.

Two freight trains a day, one in each direction, travel on that stretch of track near the I-95 overpass in Ridley Township, Amtrak reported. The speed limit in that area is 110 mph for passenger trains and 50 mph for freight trains.

Thursday's incident happened only a few miles north of the site of another derailment two years ago. In April 2016, two Amtrak workers were killed while cleaning the tracks in Chester when an Amtrak train was mistakenly routed onto a track adjacent to where the workers were.