Hornby TT:120 TT8048 Junction Distant SIgnal
The yellow arms signify 'distant' or 'caution’ and are seen on the approach to a station or signal box, often being placed up to a mile from the signal box, depending on the speed of approaching trains. Junction distant signals indicated which route had been set for the train at the junction ahead, in time for a train to be stopped if the wrong route had been set.