Look at the attached drawing of the F3 power truck and please use the terms in it. The terms you are using are confusing.
Is your 'rail glide' the Collector assembly at the bottom center of the drawing, or the Shoe assembly at the bottom right of the drawing?
The Train Tender does not have the Collector assembly in his online list. Maybe a call to him to see if he has it or can source it for you is needed.