Here are a few technical notes regarding Alaska Railroad F units from Dan Napoliello:
All ARR F-7A's & FP-7's had single headlights. #1510 and others acquired
the double headlight doors from the ex-D&RGW units.
First F's lacked dynamic brakes; kits were installed in Anchorage, 1955-57.
By 1967, the EMD blue/yellow scheme was being replaced by black and yellow. The bright yellow started in late 1971/early 1972 with the new streamliner AuRoRa. The FP-7's when repainted in early 1972 has gray trucks for 2-3 months max.
#1502 also had the AAR Roadfreight trucks as well as Blombergs.
#1510-1512-1514 were purchased new by the ARR. I've seen a delivery photo at LaGrange of #1514 with a unit destined for Saudi Arabia. Therefore, #1514 was not a secondhand unit. Have seen an Extra 2200 South roster also saying purchased new. Had a cab ride in #1510-#1512 from Nenana to Denali, in May of 1973, one of two times I had a chance to take photos is in Anchorage; the other was March 1971.