Actually, it's not a "sister" to M160 at all; M190 is more like a diesel-electric passenger locomotive with an attached baggage-mail (later converted to all baggage) section that can handle regular passenger cars (as opposed to the lightweight trailer cars normally pulled by the M160 and other doodlebugs). Nonetheless, it is a unique and very historic piece of equipment that deserves both recognition and better treatment, and it will certainly receive both here in New Mexico, where it was last in service.