Any information on the Great Northern's EMD F7s in the 270s series?

[Great Northern Fan 54]

I know that 274AB were protection units and that 274B became BN 610 and ultimately ended up as one of Doyle McCormick's units. But I can't find anything about 270AB, 271AB, 272AB, 273AB, and 274A

[BEAUSABRE]

GN           LATER     BN

270A        368C

270B        372B

271A                     600

271B                     602

272A       474A

272B       474B

273A                     604

273B                     606

274A                     608

274B                     610            

Presumably these are the numbers they went to the scrapper (except 274B/610) with

If you want to follow it up further with such things as retirement dates, you can try consulting BN rosters or the tech & historical societies