My late father gave me a coca cola hawthorne Christmas set around 2008.  the engine connects to the coal car by a flat blade that a plastic spike on the car
fits into. Problem is that the loc and car always disconnect regardless of speed or layout to the point i put the set away for years.  My grandson
loves trains, real and toy, and I would like to set this up for christmas, but same problem.  Does anyone have a suggested coupling I can add, if It can be done, to
the loco replacing the flat blade?  At this point I would run the set without the coal car just to get it up and running

thanks for the help