With the circuit described in this article, locos that pass the return signaller can be identified. Depending on the loco number, the software can then choose a predefined track or an alternative track, or wait until the selected track is free. Just as with the full-sized version, we can now (for example) have a local train enter the station and wait at a platform for a given time to allow passengers to board, while a freight train rumbles along the freight track and a TGV speeds along a passing track.If you’re operating a good-sized model train system, it’s essential to know where every train is at any given time. Only then is it possible to properly carry out various activities, such as letting a train run along a specific track or stop at a platform. The new return signaller has been developed for this purpose. It utilizes an IR receiver that can be built into the railbed so that it is nearly invisible. Each loco transmits a unique number from its loco decoder, and this can be detected by the return signaller.