Thanks for confirming. After your comment I looked at the photo again and there is a spot where a rail seems to be cut off - a concrete pattern wouldn't do that. Must have been interesting to piece it together out of rail without the usual hardware - the joints are pretty tight.

A question semi-related to the original subject: where was WP's ferry dock? Looking at remnants of the line in Google (based on diagonal property boundaries showing where the line went through Potrero Hill - yes I do remember the fire that prompted finally filling in the tunnel - it looks like it might have turned east on 23rd Street. There's a concrete structure at the bay shore, but it looks more like a sewer outfall than a pier anchor. And there aren't any remnants of a diamond in the leftover Illinois St. rails at 23rd, and if there ever were tracks on 23rd they were cleaned out a long time ago. So I'm not sure.

Also - did the WP complex get used after the tunnel closure? Supposedly SP handled any remaining local switching for WP after that.