(1) The transmitter has four buttons, labelled A, B, C & D. Pressing and holding "A" (accelerate) will slowly increase the track voltage. If held for about 8s, the voltage will reach the maximum. If "A" is released at any time before the maximum voltage is reached, that level will remain indefinitely.

(2) Pressing and holding "B" (brake) for about 6s will reduce the voltage to zero. Again, if "B" is released at any time, the voltage will remain at that level indefinitely.

(3) As the voltage reduces to less than 1/8th of maximum, the control becomes "finer". As a result, "B" must be held for another 2s to reduce the voltage by the last 1/8th. This allows better shunting control.

(4) Pressing button "C" for about 0.5s will select one direction of travel. Pressing "D" for 0.5s will select the other direction. These will work only if the speed is less than 1/8th of maximum.

(5) If "C" or "D" are pressed when the voltage is greater than 1/8th maximum, this will result in an "emergency brake" application. This results in the output voltage being reduced from maximum to zero in 1s.

The unit can be inserted between the existing train controller and the track to provide "walkround" control. If necessary, it could also be powered from a separate transformer.