Williams Reversing Board Info

[New ChooChoo]

      The reversing board that is in the Williams tender with sound. How do they control the engine? I dont see any wiring running from the tender to the engine. Does it operate the engine through the power in the rails? I assume the tender is a pullalong unit Also is it possible to connect a Railsounds unit to the board plugged in like the Williams unit is without burning up the board or the railsounds unit?

[WKT58]

The electronic board connected to the loudspeaker inside the tender is the Tru-Blast whistle sound board controller.  The reversing board is inside the boiler of the steam locomotive wired to the motor.