You can also "cheat" and figure out the phase of an Amtrak F40PH by its road number:
Phase I (Nos. 200-229) featured 1500-gallon fuel tanks mounted just in front of the rear truck.
Phase II (Nos. 230-328) had larger (1800 gallons) fuel tanks mounted just behind the front truck.
Phase III (Nos. 329-400) were similar to Phase II F40PHs, but had EMD's Q-style (quiet) radiator fans.
Hope this helps,
DFF
P.S. I've never seen those angular fuel tanks on an F40PH before. They must be a replacement for some reason.
The CSX F40's have a longer EMD 2600 gal fuel tank (I believe, based on some posts on Trainorders) , and the battery box was moved back. I think I am going to try to model that by using the fuel tank off the Kato GP50 that I have, or possibly cutting down an Atlas GP40 tank ...