This is a Rectify Series drop-in speaker system for various Walthers Proto and Mainline locomotives using the 28mm round speaker encased within two weight halves held together by screws. No modifications are required to replace the factory speaker.


The speaker is a press-fit in the stock cavity, firing down through the frame. The loose half of the weight is discarded.


Two different speaker systems are available, differing only in their height from the flat-side to the curve’s apex. The UNI1 is 18mmH while the UNI2 is slightly shorter at 16mmH. You can measure the distance between the top of the drive-shaft and the peak of the curve to determine which you’ll need. If in doubt, get the shorter UNI2.


I have installed the taller, UNI1 in Mainline Phase II GP9s and Proto U30Bs. I have installed the shorter UNI2 in Proto GP20s, SD9s and some GP30s (GP30s with the thick ridge behind the cab should use the GP30 speaker).


The speakers come fully assembled and tested.


Dimensions are:

The WLPM-UNI1-RC1: 18mmH x 15mmW x 28mmDia

The WLPM-UNI2-RC1: 16mmH x 15mmW x 28mmDia



Proto GP30

Mainline GP9


Walthers Proto & Mainline Universal