As told to me by my Father, that wreck on the NYCRR bridge over Ellicot Creek was a result of a misunderstanding of radio instructions to one of the trains. 1962 was still early in the use of radios.
There were two trains, one was an engine and a few cars with a caboose. It was switching around the former Spaulding Fiber Plant (on Wheeler St, City of Tonawanda) about a half mile south from that bridge and about 2 miles from the yard in North Tonawanda.
This train received radio instructions to "Get in the Clear". The crew took that to mean "go back to the yard and get off the main track". So they headed North (coming into that photo from the left side).
The Dispatcher said (or meant to say depending on who you asked); "Stay in the Clear", meaning pull into the siding they were switching and close up the main track switch. The siding at that factory could hold half a dozen cars easy.
The dispatcher thought the switching crew was off the main, and sent the train with the empty hoppers south from the yard in N. Tonawanda.
There was no signal between the the two trains that would warn the coal train to stop. That was a double track section without bidirectional signalling, the switching crew was going against the normal traffic flow so there was no signal for them.
There are curves leading up to both sides of that bridge so neither crew saw the other train until it was too late.
An unfortunate misunderstanding, however (IMHO) the dispatcher should not have released the coal train without first confirming the switching crew was indeed "In the Clear" (off the main track someplace). At that time that track was "dark territory" and the Dispatcher could not see what tracks were occupied. The Dispatcher was responsible for knowing (or finding out with a radio call) that the main track was clear before releasing a train into it.
After that wreck the operating crews had to write down radio instructions regarding occupying main tracks and read them back much like a tower operator would do with a written train order received over the phone from a dispatcher.
There was another tragedy on that bridge back in the late 60's early 70's. There was a neighborhood on the east side of the creek and the kids went to school on the west side of the creek. The nearest road/pedestrian bridge that crosses the creek is about an 1/8 mile north of that bridge, adding a whole quarter mile to the trek to/from school. So kids being kids (Junior high school ~12-14 years old) that railroad bridge became a convenient "short cut" on the way to/from school. Unfortunately the day came when kids were on the bridge and two trains crossed it at the same time. It was a while ago, but I believe there where 2 or 3 fatalities with one kid jumping into the Creek but not surviving.
RIP folks, Kevin.