Here's one that might be more of a challenge: ;)

How about-----Glendale Train-New Riders of the Purple Sage
-----Boxcars-Butch Hancock

Some of my favourites that come to mind right away are :

900 Miles by Odetta

Train Song by Vashti Bunyan (also a nice version of the same song done by Feist and Ben Gibbard)

The L & N by Jeannie Ritchie

Canadian Railroad Trilogy by Gordon Lightfoot

Freight Train by Elizabeth Cotton

"Monkey and the Engineer" Bob Weir/GD
"Back on the Train" -Phish

"Train Junkie" -Greensky Bluegrass
"Randall Collins" -Norman Blake
"Midnight Special" is technically a train song


Train adjacent (don't know if these have to be ABOUT trains, or just have trains or train themes in them):
"I Know you Rider" -Trad/Grateful Dead (maybe not a train song per se, but got that one line)
"Ginseng Sullivan" -Norman Blake (again, not a straight up train song)
"Marie" by Townes Van Zandt (this is a real downer of a song, though)
"No Expectations" -Stones ("take me to the station, put me on a train")

That Elvis tune
Mystery Train

Second that - of my favorite Doc so songs.

Arthur "Big Boy" Crudup Mean Old Frisco Blues

https://youtu.be/X6d2GTYG4lc

Steel Rails
Paddy on the Railway
Freight Train Blues
She Caught the Katy
Cherry River Line
Yodel Train
San Francisco Bay Blues
D***ed Old Piney Mountain
Pecos River Queen
Linin' Track

https://youtu.be/V41gDDWEPso

a recent discovery of mine Ramblin’ Man by the legendary Hank Williams.

train songs
 

"Glendale Train", by The New Riders of the Purple Sage.

Old train is a great tune. I like Rice’s version from Manzanita. Josh Turner and his friends do an awesome version here:

https://youtu.be/KkKLKM98GNU

A bit on the edge of train songs but a great one anyway.

Corey's Coming by Harry Chapin

https://youtu.be/TfTtG_awEJY