Key Imports C-9

[ATSF_Ron]

Thanks, Peteski.  Yes, the wheels simply spin in place.  I may attempt to put more weight up front later this week.  We'll see...

[Cajonpassfan]

Just stick a bit of weight on top of the loco.... the 1/4 oz. weights with double stick tape are good for this... to see how she does, and how much more  weight is necessary to achieve satisfactory  performance. You may or may not have the room inside, but at least you'll know whether this is the problem.
Good luck, Otto

[mmagliaro]

When the engine is on the track, see if you can gently lift JUST the pilot truck up off the rails without the body of the engine
moving at all (maybe poke an Xacto under there and try to lift the pilot truck arm).  We want to confirm that the pilot truck has some free upward play and isn't taking weight off the front drivers.  You could also remove it entirely and see if the pulling power dramatically improves.

The pilot truck arm on that C-9 is an arc-shaped metal strip, and it can easily get bent so that too much weight from the engine is being carried by it.  I wouldn't be surprised if somebody before you was having derailment issues with the pilot wheels and bent it down to "fix" the problem.

[ATSF_Ron]

Max, after reading your post I started playing around with the front truck.  Turns out I had the dang thing on upside down!  UGH!  Anyway, the pulling power is MUCH improved, thanks.  Now there's a random shorting issue that wasn't there before, but I know what it probably is.  Instead of one bottom plate, there are two.  There's a thinner second one under the outside one.  It was a real bugger getting the two plates lined up properly, along with making sure the brake shoes were straight at the same time when reassembling.  I'm virtually certain it's something in that setup, as this random shorting wasn't there before the traction tire replacement.  It's late, so the final tweaking will have to wait.  I feel like I'm almost there!

[mmagliaro]

YES!!!!!
And yes, I didn't even start getting into that, but I know about the two plates.  It's important to get them lined up with each other as accurately as you can so one doesn't stick out over an edge and short to a driver.  Just put it on its back and make sure when you slide the drivers all the way one way and the other, that they cannot possibly touch the frame, that plate, or any brake shoe.  I would also suspect the pilot wheels of grazing the insides of the cylinders or the front edge of the frame.