Standard Features:

Indicates Actual Speed up to 10 MPH

Quality Moving-Coil Meter - 70 mm x 60 mm

Works from magnetic Wheel Sensor (supplied)

Multi-function configuration button

Easy entry / display of Wheel diameter

Adjustable Over-Speed Indicator - illuminates when pre-set speed is exceeded

Odometer Function (up to 99.99 miles recorded)

Accommodates Wheel diameters from 1 to 9.999"

Can be run from a 9V PP3 / MN1604 / 6LR61 battery -  run it from your Driving Truck wheels - useful for Steam Locos

                                      Alternative Options

Odometer recording up to 999.9 miles

Wheel diameters from 10 to 99.99"

                                      Extra Cost Options

Wheel-slip Indication Function (requires additional Sensor)

Relay that closes when speed is above Over-Speed Setting, or

Relay that closes when vehicle is moving

Other calibrations or Metric Scales  - ask for details

Get Documentation

Price: 55 + Postage

Welcome to Magpie Computer Development's Locomotive Accessory Section, where you will find information about the following products:


Multi-LED Searchlight-type 2-3-4 Aspect Signal Assembly for 5" &  7 1/4"

Link to Magpie Computer Developments Home Page

This Signal  uses a multi-LED array to produce the 3 Aspect colours of RED, YELLOW & GREEN The Array is fitted to a 68 mm diameter clear diffusing lens; this assembly can be easily installed into your own signal head    Shown here is a 4-aspect signal, which has a 3-colour assembly in the lower position, and a second assembly in the upper position, which shows Yellow only.

The assembly can handle 2-Aspect signals as well.

There is also a control PCB which contains all the necessary electronics, and provides 2 different 'flavours' of control:

1. Direct 3-bulb replacement, and

2. A two-wire buss system, principally for new signalling installations, using computer control.

Option 1 - Direct 3-bulb replacement.

Many club tracks operate 3-aspect signal heads that use 3 separate bulbs, each behind a coloured lens. Thus, there are 4-wires going to the head, a 0V common wire, and a 12 or 24V wire for each of the 3 bulbs. These 4 wires are simply connected to the appropriate  terminals on the control board, and the display will show the colour determined by which of the 3 'bulb'  wires has a voltage. The unit draws its operating power from whichever 'colour' wire is active. Average current consumption is around 150 mA.

Option 2 - Two-wire buss.

Using this option, just 4 wires are looped around the track to each control board - 2 for power (0V and 12/24V), and two for digital control data. This option also provides (at each control board) 4 opto-isolated inputs for track-circuits, point detection, etc, together with 2 Auxiliary outputs, which can be used for  Call-ON, route indication, point operation, etc. Each control board is configured with a unique address. The computer control system continually sends commands to each board, telling it which aspect  to show, and which (if any) Auxiliary output should be ON. The board responds to its command message with the current state of its inputs.

Searchlight-type Signal  Assembly

These displays are very difficult to photograph, principally because of the PWM technique that's  used to 'mix' the intensity of the different colour LEDs in order to provide the proper colours. Fortunately for us, our eyes can cope perfectly. But hopefully they will give you the general idea. The actual colours are what you would expect to see, and are clearly visible from much greater distances than filament bulbs.