In the 1920s, Southern Pacific had a need for powerful locomotives, but found that the new articulated 2-8-8-2's did not work well for them. They were a hazard to the crews when traveling through the long tunnels and snow sheds on their system. The exhaust fumes were capable of blinding and suffocating crewmembers, so to resolve this problem, the Southern Pacific decided to run in reverse. The next articulated engines from Baldwin were built with the cabs in the forward position. The SP went on to build many classes of these "Cab-Forwards".
 
Features ABS plastic body with heavy die cast chassis, 5-pole can motor with skew-wound armature, operating knuckle couplers and many separately applied details. Will operate on Code 70, 83 and 100 rail. Recommended minimum radius is 22 inches.
 
AC4 SP #4102
AC5 SP #4112
AC5 SP #4117
AC4 SP #4100
AC5 SP #4125
AC4 Painted, Unlettered
AC5 Painted, Unlettered