For the TL-4 Traffic Signal, Bachmann did not even list the production number of this item in their catalogs, save that they did show it in the 1951 catalog among the contents of the CD-5 Dealer Window and Counter Display Unit.
This traffic signal was originally available in 1951 with the release on the ON-5 Outdoor Necessities card. Starting in 1952, it could be found in the ST-1 Street Accessories Unit, and the SU-5 Shopping Unit. The only place that this item could be found in subsequent years were in the various Master Units that contained them.
It was only produced in the common GREEN color that Bachmann used on many of their small items.