They originally wanted streamlined power, and apparently the FPA4s were then (circa 1988) more readily available than EMD Fs. No, they never got any B-units, although the Grand Canyon Ry. did. They did buy an Alco RS-11 from the California Western. The intent was to scrap it for parts, but it turned out to be in pretty good shape so they used it instead.

They also have two GE 80-tonners, a rebuilt GP9, a GP20 borrowed from Sierra Northern, and a high-nose GP38-2. I heard the new unit is supposed to be one of those Knoxville low-emission things (probably like California Northern got) but I don't know exactly what it looks like or why they would only get one. I've also heard that they are going to return two of the FPA4s to service. Of course, the plague has put a wrench in the gears. I too would welcome any news.