The Cab04eR has the same specification as the Cab04e except that a radio board and battery holder has been added for operation as a radio throttle while retaining the plug capability of the CAB04e.
The Cab04ER uses a more conventional knob for speed control and features a digital encoder (Cab04e). Both varieties of the Cab04 can be set to YARD mode. Yard mode makes the speed knob act as a “center off” speed control. Turn the knob to the right and the loco will increase speed in the forward direction. Turn it to the left and speed will decrease until it gets to zero then it will start to increase speed in the reverse direction the farther you turn it to the left.