differences between htcr-1 and htcr-2 trucks?

[lyled1117]

'Fraid these are too modern for me. I wonder if someone can point out any noticeable differences between these two trucks. I need to identify what I have on an Athearn SD70MAC. According to the exploded parts diagram, it could be either. If it helps to identify, the loco in question is a BN SD70MAC, old enough to be in the Genesis yellow/blue box, product number is in the G64xx range if that helps. I have a damaged sideframe I'd like to see if I can get a replacement, just need to know what I'm replacing

Edited to add, on the current truck there is a molded in HTCR , imitating something embossed on the real thing. Any chance later trucks had a 2 or II after the HTCR?  That would suggest what I have are HTCR-1s, having come first and no # ID necessary

Lyle D

[EMDX6043]

Here's a link to a brief description: HTCR=I/II

Differences on the II are the addition of an electronic parking brake, 45" wheels and split bearing adaptors. The text notes that the II will fit any 70-series unit, but overall the appearance is similar to the HTCR-I.

Photo below from Mike Danemann, illustrating an HTCR-II being reassembled.

[ssgburme]

A lot of the later BNsf Aces have the radial truck frame without the linkage.