I just came upon this one. I do not know if it has been posted before and I apologize if it is a repeat.
In any event, it is good footage of New York City New Haven and New York Central electric plus some diesel action in July 1961.
Keep your eyes open for the S motor hops from/to Mott Haven including the 20th Century being taken to Mott Haven for servicing.
I was a kid then and remember all of these trains. I thought this was the way it always was and that it would always be just like this.