The service manual is here, pages 255-256 (9-5 and 9-6 at bottom of page).
https://www.lionelsupport.com/media/supplements/Supplement1to9/1Complete.pdf

Larry

For now I cut a little sliver of a magnet to hold the coupler handle up and tighter, may have to take it to Kirkland Trains in Kirkland Wa. near my location.

Any dirt or grease can be cleaned off with Naphtha, available at a hardware or paint store. Scrape off any dirt on the wheels with an X-Acto knife or the blade of a screwdriver, then finish cleaning the wheels with Q-Tips dipped in the Naphtha. A drop of oil on the axles where they enter the wheels will allow better rolling.

The coupler opening is caused by a weak spring 480-38
http://www.ttender.com/weblistpictures/480-38.jpg

You'll need the rivet to hold the spring in place, #2343-66
http://www.ttender.com/list/num8.htm

Replacing these parts will keep the coupler from opening in use.


Larry