Lionel introduced this light in 1949 as a cost cutting measure when compared to the previously used No. 35. They replaced the screw in socket used on the No. 35 with a new one that took a bayonet mounted light bulb (No. L53) that were just coming on the market. To hold this lamp in place they needed to install a spring (Part No. R-91) in the socket. This insured that these lamps would not shake loose during shipment to their dealers. To offset the cost of this new socket spring the plug-in wiring receptacles in the base were illuminated to be replaced by wires. One wire was grounded to the base of the lamp and the other went up the stem to the lamp socket.

The casting was changed after initial assembly problems were uncovered. These changes are not significant enough to note variations.

Dimensions: 1-1/4 inch base, 6 inches high.