The photo shows the face of the radio-handheld "throttles" Mike Moir developed for use on the C&NE.   The handhelds are XBee-based, which is a single chip containing a processor and a radio.  The XBee "chips" can be programmed to match your use; here Mike has programmed the XBee to accept inputs from knobs and buttons. The handhelds contain a 9-volt battery, the XBee chip mounted on a commercially available board and the knobs and buttons you see.

The handheld is 2.5 inches by 5 inches. They are light and easy to hold.

Pretty much all the "smarts" are in ProTrak, so it is easy to change how the throttles work, although since 2013 there have been minimal changes.

The throttles have two modes; "direct" and "power-modeling".  In direct mode the "Throttle" knob directly controls speed. In "power-modeling" mode ProTrak takes data about train location (grade, curvature), the train and throttle/brake settings and calculates the proper train speed by solving the equation of motion (.... a train performance calculator working in real time in ProTrak).

The "Options" lever allows for other functions; the Light, Bell and Horn buttons do other things. e.g. in Option mode the Bell button controls the sound mute.

I currently have 12 of these throttles and plan to add four more. 

                Jim