SEE ALSO: Norfolk Southern Trains Collide, Derailing Into Lehigh River
The road was reopened around 3 p.m., Lower Saucon police said.
The collision happened on tracks parallel to Riverside Drive around 7:15 a.m., officials have said.
The National Transportation Safety Board said an eastbound train hit a parked train on the same tracks, causing both to derail. Loose cars from one of those trains collided with a third one, causing it to derail as well, according to investigators' preliminary findings.
All three were Norfolk Southern trains.
No injuries were reported, though diesel from one locomotive spilled into the Lehigh River and polypropylene pellets spilled out of a train car, authorities said over the weekend.
Northampton County officials said Saturday there is "currently no danger to the general public due to the derailment."
NTSB said it sent a team of "experts in train operations, signals & train control, mechanical systems, and human performance" to Lower Saucon. Their investigation is ongoing and Norfolk Southern said it is cooperating with regulators.
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