Train Position Sensor Kit

Train Position Sensor & Lights Relay

The Train Position Sensor Kit (TPS) can be used on its own or with the Relay Card (EM134 or EM135). The kit consists of the following components. This type of indication is used to indicate the position or movement of the train in hidden areas of your layout, such as tunnels and underground areas, or parts of the layout you just can not see from the control area.

SW925  Reed Switch SW932  Magnet SL101  Red LED SL300  LED Holder RE137  Dropping Resistor CA125  Capacitor 470mF 16v
All these components are sold separately as you may need more magnets or more LED's for a repeat indicator. Just use the part number to order.
Train Position The basic circuit for a simple panel indication is shown opposite. The higher the value of the capacitor the longer the LED will stay on - the value in the kit will keep the LED on for 2 to 4 sec.
The magnet is fitted to the underside of the train/s, the reed switch is fitted inbetween the sleepers or across the sleepers (watch out for clearance with the magnet - the operating distance from reed to magnet can be up to 10mm apart). When the train passes over the reed, the reed switches ON which illuminates the LED on the control panel. Once the train has passed the reed the LED will switch OFF, this could turn out to be just a flash depending on the speed of the train. The capacitor is there to hold the LED ON for 2 to 4 seconds
Train Movement 1 This is the simplest circuit to show movement of the train. As it passes each reed switch SW1 to SW4 the LED will flash ON for a few seconds. In this case you may need to reduce the value of the capacitor otherwise the delay will keep it ON for too long so you will not see the LED go ON & OFF to indicate travel.
The magnet is fitted to the underside of the train/s, the reed switch is fitted in between the sleepers or across the sleepers (watch out for clearance with the magnet - the operating distance from reed to magnet can be up to 10mm apart). Position the next reed switch approximately 300mm to 500mm from the previous one and so on. The distance apart will depend a lot on the size of your layout. When the train passes over the reed, the reed switches ON which illuminates the LED on the control panel. Once the train has passed the reed the LED will switch OFF, when the train reaches the next reed the LED will switch ON again and so on.