It appears to be at Frankford Junction. The ex-PRR mainline sweeps in a broad left-hand curve (moving northeast towards NY). Back in the late 70s, my recollection is that it was 60 mph territory because of the curve. There are 4 mainline tracks. There used to be (may not be anymore) a separate Conrail industrial track (in poor condition) on the inside of the curve. To the outside, there are several tracks that split off from the main into the yard, then continue across a bridge towards Atlantic City.

In the accident photos, there is a badly twisted catenary bridge. It looks to me like it's from those junction tracks, not the mainline.

The PRR had a bad derailment just south of this many years ago.

-- Steve