The switch machine housing had four flat plastic colored lens (two of each color) to indicate the direction of the switch. These flat lenses would also be used on the early issues (1946-49) of the controller (Part No. 1121C-60). Later issues, after 1949, would use the rounded top rubberized lenses that were used on the most commonly found version of the No. 151 Semaphore.
The lamps that were used in the switch motor housing were screw base No. L430 prior to 1950 when they changed to bayonet base lamps No. L431. The same lamps were used in the controller except that the change over to bayonet base occurred in 1949.
These switches would be superseded in 1952 by the No. 1122. Although similar in appearance the single controller for the No. 1122 switches (Part No. 1122-100) will not work with the No. 1121. The main difference between these two switches is that the No. 1121 lacks the non-derailing feature that was added to the No. 1122 in 1952.
Individual left and right hand switches were issued independently of the set described here and they were issued with a No. 022C Controller.
These controllers operated the switch with no problem, but the lights on the controller would not light up without electrical modification to the switch itself.