Update at 1:13 a.m. ET:
Officials have started the process of notifying families, it was announced at a press conference, though it wasn't certain if everyone on the train had been accounted for. The number of injured transported to the hospital was increased to 65, but the number of dead remained at five.
Philadelphia Mayor Michael Nutter said some major work would have to wait until the morning, as operating some of the heavy machinery in the dark wouldn't be safe. The next press conference also likely will wait until late Wednesday morning, he said.