Yellow switched to dummy pintles on the pups and slack plungers on the converters a long time ago. Smart move IMHO. Easier to switch out a converter with a bad plunger than a pup loaded with freight with same.Ground has a different setup for their gears. They have the dummy pintle hook on the back of their pups and the locking plunger on the gear. Pointed this out several years ago to a witless TM, was told, oh we'll figure it out. Figure away boys!