CM3 Trackmobile near Wasilla.
Photo courtesy of Louis Friend
A trackmobile is a vehicle with a bi-modal transport
system providing an efficient and economical means of switching railcars
within industrial plants and railroad terminals.
All Trackmobile vehicle models utilize two unique
features that make them much more efficient and economical than conventional
switching locomotives. First, a bi-modal wheel system in which steel wheels
are used in the rail-working mode and rubber tired wheels are used to facilitate
movement of the vehicle over roadway to new rail-working locations. And
second, special couplers which transfer weight from the railcar to the
Trackmobile, thus providing a tractive effort equal to much larger conventional