Good news is filling the smokebox with lead birdshot and epoxy seams to have fixed the wheelie problem, but I still suspect I need to add more weight into the tank to help it pull anything and if I want to add an engineer figure. replacing the pilot beam with one filled with shot was one suggestion I might try, otherwise its the tank that will get birdshot added.
Next major issue is adding couplers, the front not so worried about but the rear is definitively going to have to be swing mounted.