Give adequate notice to trains approaching stop signals by flicking down this single distant signal place this hornby accessory r172 down the line from a home signal leaving an appropriate braking distance between the two should your train need to come to a sudden halt it39s not just a practical model lifesaver but it also looks fantastic thanks to the highly detailed features found all around it it39s a great way to expand an existing set and goes a long way to adding a touch of au