Just got my new proto 3 premier GS 4 back from with a new drawbar. It fits on so loose that it falls of the tender pins when pulling a 10 car mth premier streamline passenger cars or will stay on at speeds no faster than 15 smph. Any ideas on how to fix it. Not happy at all with that drawbar. It used to snap when it was bottomed out and stay on but now it just slides on. thank for any help