Install new springs to kick the contacts off, problems disappear. Install new stationary contacts, especially carbons to add height. The sooner the contacts meet, the more spring you get for the release. But not too soon...
Your last option. You can also install a thin strip of non-magnetic metal (brass)between the cores. This last information comes from 1920's elevator books. Clean switch again.
Make sure the hinges for the movable contacts specs. include washers. One floor switch was sticking and a thin copper washer was added to the hinge to try to align the movable arm contact better (the magnetic forces tends to align the core just fine). The washer had a burr and was causing the sticking. Checked parts list, no washer, had washer removed. The floor coil operates correctly. Clean switch again.
Thanks
The GS27 in this case refers to a Otis mod of AC controller with a DC overlay for a new retiring cam motor and cam motor- ?automatic gate closer? Also changed was a direct AC brake for DC brake and a DC brake control panel was added. Original Sheet #4012, date July 19, 1920.
Sheet #GS4-3329F, date April 16, 1954 (condensed? wiring diagram). GS4- note- Added Potential Switch.
The expanded wiring diagram GS4-3329F starts #3329D, date March ?, 1917,then #3329E March 26, 1917, then #3329F May 10, 1917. Ends #GS4-3329F, date April 16, 1954. Assume #3329 is the original sheet #.
As far as your question about the later number designations, Christy Collett, I don't know but started at least by 8-CIF6834A, date start 1,24,1949. final? Jan 16, 1953.