There's no freight trackage left along the Embarcadero. The Alcos can be found in Hunters Point, southeast of where Third Street crosses Islais Creek, in the vicinity of Cargo Way and Evans Ave. The outside connection is with the UP's Quint St. lead off the Caltrain line. They mostly switch cars of "dirty dirt" that are picked up by the UP's South City Switcher (based out of South San Francisco); the UP job goes to work about 0600 M-F but they don't necessarily go there every day. A few months ago, I went over there and found the office staff pretty friendly and was able to photograph the Alcos (and the ex-Navy repowered Baldwin) with no problems. Find the yard full of dirty-dirt cars and look for a prefab office that says "San Francisco Shortline Railroad" (or something like that). For those unfamiliar with the area, it's definitely not somewhere to be after dark, and keep the bling out of sight.