Could have been the overhead catenary arcing when the train went over. it’s possible the “explosion” was just the train derailing, as some people will call any loud noise a explosion.
my buddy's on scene on the tracks ... he just called me ... he said there's a crater in the track that the FBI won't let anybody near ... bomb squad on scene with bomb sniffer dogs ... i believe the engineer is one of the fatalities but not confirmed ... now we've seen plenty of derailments ... he said he'd never seen nothing like it ... concrete ties obliterated ... cat poles hanging ... my opinion ... something forced that train off the track and i'm starting to think with the info i just got that something sinister occured ...
And from another poster:
The damage to the one mangled, V'd car is bizarre. Similar accident on Pennsy in same area in 1943. Tank car on adjacent track but does not seem to have been involved or disturbed. The force needed to bend an Amfleet in half is tremendous. Built by Budd to withstand 800,000 pound compression load force at the ends and 300,000 lb horizontal load at the sides. I don't understand it! I was praying no fataltities, but someone has posted 5 dead. I am saddened by this news. NBC10 Philly just mentioned that rails were extremenly bent and what force would be needed to bend them by the derailed loco. The loco is almost 217,000 pounds. I am more interested in how that Amfleet became so mangled. I am totally perplexed and shocked at this!
If this is any thing other than a mechanical/track malfunction or unintentional human error, we have a new national security problem, though the Feds would likely try to bury it like TWA 800.