I can't comment on Philadelphia Steam in the 70s (I was born in the 80s), but I am curious about how that soundtrack was chosen! If anything we should have heard a GG1's foghorn, right?
One of my favorite movies is Trading Places. It checks a lot of boxes for me: Eddie Murphy is in there, it's based in Philly (I went to college and grad school in Phiily), the Juice Train makes a cameo (that's my favorite train), we get a basic understanding of futures trading, and it's one of only two times I've ever laughed at a character in blackface (Ire, ire, ire!).
The characters also spend an evening on the northeast corridor and that's where the railfans have a fit. First of all, their train has an Amfleet Baggage car. It looks like they had a vinyl tarp painted in Phase I colors pinned over the windows of a coach. Second, the train has an engine swap or something because it starts out with an E60 and then there's an AEM7 at some point.
Oh, and the compartments!!! I've been riding on the northeast corridor for 20 years and I have never seen such fine coach accommodations! When I was younger, I assumed that was the interior of a viewliner, but now I guess that was just a Hollywood set designed by someone who has never been on an Amtrak train. It was a VERY convincing interior.
I want a "Baltimore Delta Club" amfleet coach now. I should print a decal...