Well, I guess I'll have to clear up some errors on this subject here as well...

First off, the M.190 is not a "sister" to any of ATSF's other "doodlebugs"; it was actually built (in 1932) as an 900 h.p., 90-ft. articulated baggage motorcar that was designed to pull four standard passenger cars at speeds of up to 80 MPH; this performance was made possible through the use of a one-of-a-kind Winton 12-194 engine and four traction motors in the first two trucks which gave the M.190 a calculated tractive effort of 50,500 lbs. (as opposed to the other motorcars, which only developed 400 or 535 h.p. and could only pull either lightweight trailer cars or a single lightwieght passenger car). The Winton engine was replaced after WWII with a EMD 12-567 diesel and a Vapor-Clarkson steam generator was installed in place of the original Otis model sometime afterward, and the rear power truck was de-motored when M.190 was assigned to the Clovis-Carlsbad run (usually pulling car 3797 as mentioned in Mr. Gray's post). For the most part, the M.190 is more of a predecessor to the power cars used on many early lightweight trains (like UP's early Pullman-Standard "City" trains and the Budd-built CB&Q "Zephyr" and BM-MEC "Flying Yankee" trains) instead of being just another "doodlebug".

M.160, while painted in the same Warbonnet passenger scheme as the M.190 (both cars were repainted as such when assigned to the Clovis-Carlsbad service) is different not only from the M.190, but (like scrapped sister cars M.161 and M.162) also from the other Santa Fe motorcars. It is one of three Brill 80-ft. RPO-baggage cars built in 1931-32; like the M.190, all were rebuilt after WWII with EMD diesels (6-567Bs with the same horsepower rating as the original gasoline engines, in this case) and they also were fitted with automatic transition (becoming the only Santa Fe motorcars equipped with this feature). As mentioned earlier, M.160 was assigned to the Clovis-Carlsbad run, trains 25 and 26, along with M.190 and was fitted with a steam generator and repainted for this service.