mmmmmmmmmmmmmmSouthern Pacific SPMW 4679 Flatcar

This ex SP work train flat car found a new life as a service road bridge (no, it's not supporting the locomotive) a short distance timetable east of Santa Rosa,
New Mexico. At the time of the photo, mid-1984, Wx4 staff calculated that this must be an early-1900's Pressed Steel Car Company product, so we thought
that an underside shot might be useful, especially since this may have been the only like SP flat still extant at the time. Is it still there?

What we DO know about the car comes from the SPH&TS Southern Pacific Car Roster as of January 31, 1956: It was converted to a MW "Rdy Flat" from gondola 54977 on Oct. 19, 1928. Unfortunately, the roster on page 67 of Tony Thompson's Southern Pacific Freight Cars Volume 1, Gondols and Stock Cars lists no such number. Hmm, hmm...