Circuitron 800-5201 DT-1 Grade Crossing Detection Unit

The Circuitron DT-1 is a bi -directional detection circuit designed for DC track power that provides an output whenever one of its Opto- Sensors is covered by a piece of rolling stock. Absolutely no modifications to the rolling stock are necessary. 4 Opto-Sensors are provided, 2 of which are used for each direction of travel. The two Opto-Sensors for each direction are wired in series, and a single sensitivity control for each direction adjusts the pair to compensate for varying levels of room light.

The DT-1 connects to the track to determine track polarity and activates only the Opto-Sensor set for that direction of travel. This ensures that the output of the DT-1 turns off just after the last car clears the crossing in either direction of travel.