Do you have any information, including a wiring diagram, that can help me wire my Lionel No. 450 Operating Signal Bridge using AC relays? Thanks! — Fred Richmond
As Lionel operators certainly know, the 450 Signal Bridge, which was designed to span two lines of track, is equipped with two signal heads. They have bayonet-mounted light bulbs that can change from green to red when a train approaches. The weight of the locomotive and rolling stock pressed the track onto a No. 153C Contactor placed beneath it and wired to clips in the plastic base of the signal bridge. The electrical contact caused the color of the signal indicator to change. To solve your problem, Fred, you’ll need a single-pole double-throw (SPDT) relay for each signal head on the bridge. Typically, you’ll need power to the relay coil; additionally, you should connect the ground path of the coil to whatever you use to activate it (contactor, insulated rail, and so forth).
When the train reaches the activator, the relay should close. Once this is done it’s time to wire the lights. The relay will have a normally open contact and a normally closed contact as well as the moveable contact. The 450 will have three spring clips on the bottom of each leg base. The hot wire for the lights will go into the moveable contact lug on the relay. The ground for the lights will go to the ground spring clip on the signal. The normally open lug will go to the red light spring clip; the normally closed lug will go to the green light spring clip. As a train approaches and closes the relay, the green light will go out and the red light will come on.
