I recently acquired a Gem brass PRR turbine. It would be a fine runner except that both the leading and trailing truck won't stay on the rails. These are six wheel trucks that have a curved slot into which a simple vertical spindle fits giving the truck a pivot point. There is a spring and I have tried adding weight to the truck in the form of 1/4 ounce square tape-ons. Because of the long boiler, this engine has a lot of overhang fore and aft as the driver's wheel base is quite short. I'm thinking of trying to enlarge the slot and see if that improves tracking but before I take an irrevocable step, I'd like to know if anybody else has had this problem and solved it. This engine runs fine with both trucks removed but it looks really odd paddling around the layout without it's trucks!
I can fix it, but I need to have it shipped to me.
If I had to guess, you'd be much further ahead changing the curves. A long-framed steamer with extra long trucks won't be happy on curves less than about 45". If you already have those, and it doesn't matter what the literature for the loco claims for it, but it still doesn't work on them......
On my Custom Brass S-2 the rear truck is "nose mounted". The mtg screw is forward of the front wheel set on the truck frame. Also the front wheel set is "blind". I also added weight to the truck as it just floated. The front truck has two curved slots, one for the mtg screw and one for a gude pin. I know you have a Gem but this is how another mfg did it.
Makes me wonder two things. Was the Custom Brass model after the Gem and perhaps this was the fix that worked to solve the Gem's problems?
And, maybe both the Gem and Custom Brass models were built by the same offshore builder?
Mike Lehman
Urbana, IL