MTH Premier 20-21735-1 O Scale GE AC4400 Diesel Union Pacific UP 6297 PS3 Era_1949+ an evolution of the SD70MAC

an evolution of the SD70MAC

no cabless booster B units were sold

High-strength glue and bead design

Three different body types

MTH Premier 20-21735-1 O Scale GE AC4400 Diesel Union Pacific UP 6297 PS3 Era_1949+ an evolution of the SD70MACMTH Premier 20 21735 1 O Scale GE AC4400 Diesel Union Pacific UP 6297 PS3 From the dawn of dieselization through its first six decades, virtually every American diesel locomotive used DC traction motors. By the early 1990s, however, a series of technological advances allowed designers to tap the inherent superiority of AC traction namely, the ability of an AC motor to start a heavier load than a DC motor, with the same prime mover. The superior