As I was involved in the trade from the FRRS side, and at the risk of walking into a shark tank, as I recall the rational was that Bay Area Electric wanted to focus on the electric era of the SN. So, the SN 44 ton 146 received from the FRRS was relevant since it served alongside the electrics, but SN GP7 712 was not. We took a lot of grief for giving up the 146 and caboose 1632 (a personal favorite of mine), but they fit the BAERA mission. And I must compliment them on the excellent restoration they have given our beloved "Grandma" caboose.

Note that later the FRRS acquired SN caboose 1642, which had the bulk of its service after the electric era and was painted green to match the 712, so they make a great set. The 1642 is currently undergoing extensive exterior work leading to repainting. And we have acquired a traction motor to replace a dead one in the 712 with a goal of getting it running again.

The FRRS mission, by the way, encompasses the entire WP family through the whole history from 1903 to 1983, so SN, TS, CCT equipment are all relevant, not just WP.