The BL-2 was EMD’s response to railroad criticism that the F units left a lot to be desired in switching situations and was an attempt at greater visibility. The problem for EMD was centered around the fact that on F units the car body was part of the structural integrity of the loco. The curving side members on the BL-2 were actually the equivalent of bridge members. Then one of their engineers (Dilworth but forget his first name) came up with the GP-7 design (probably copied from Alco RS-1 engines) with the comment he wanted to make something so ugly the railroads would be forced to use it in yards and branchlines where it wouldn’t be seen. The rest is history.
The BL1/2 was the forerunner of the GP7. It proved that EMD could build a branchline switcher on a frame instead of their previous design which used a bridge truss (covered wagon type) to support their engines. It could be considered the first GP only there was room for improvement in the walkways and rearward visability.
It’s ironic that an antique/oddball like the BL-2 would set the stage for 21st century power: a full width cab in front and a ‘narrow’ road switcher style long hood in the back. I even have an HO model, painted for my imaginary ‘Ontario and Buffalo’ layout name.
The pics are kind of fuzzy but if that is the old AHM BL2 then it used the trucks from their Fairbanks Morse C Liner engine. The real BL2s had the same kind of trucks as F and GP units did, and the Proto 2000 version of the BL2 is more accurate.
There are two preserved BL2s at the National Railroad Museum in Green Bay WI by the way:
Don’t feel bad when I first saw a model of a BL-2 at a club I belong to in Sandusky it took a bit of research on railpictures.net to figure out with it is.