This Identification Guide for Lionel Electric Trains covers the "Post-war Era" only from 1945 until 1969.
LIONEL TRAINS SUPER-O GROUND LOCKON No. 61
Super-O Ground Lockon No. 61 was produced from 1957 until 1966. This lockon attached to the outside track rail and provided an electrical ground for Super-O Track. There are no variations.