Below.� Drawing of bulb exchanger.� When one bulb burns out, a solenoid is activated allowing a new bulb to swing into position.

Above. �Sighting device used on high or mast mounted color light signals with modular light units.� The device is used to help properly position the signal given its relatively narrow light beam.� It is located in only one of the light units.� The background or target needs to contain a hole to accommodate the device as shown in the photo on the left.

Left.� Light units without the sighting device have a cover installed.