After receiving the class I motors, the Portland Shops signed agreements with EMD to use them as a supplier for electrical components & trucks for smaller motors that used ABB drivetrains drivetrains. The class J roadswitchers were one of them, and the class K were another; the class K used a drivetrain much like the ones that were in GMD’s GF6C motors, EMD’s radial trucks, and Portland carbodies.

Six were built (three streamlined, three steeplecabs) and they all remain in service in 2024.