Mike--
Try VERY GENTLY bending the cowcatcher up just a little. Maybe even just 1/8 inch will do it. Then, either put a very thin layer of epoxy on the bottom of the cowcatcher and let it dry, or find the thinnest piece (1/32 or 1/64) of sheet styrene and cut two pieces to glue and fit the bottom of the cowcatcher. Either way, you should solve the problem. You're right, a stiffer spring will only put the loco off balance. I had the same problem with one of my brass Northerns--the epoxy did the job. Just enough to coat the bottom of the brass cowcatcher.
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
Tom,
I found the problem. I put the locomotive on a test track and turned off the lights and immediately saw the sparks. It seems that the Cow catcher is barely touching the tops of the rail heads. When it does make contact, it causes a nice spark...LOL
Question is, how do I fix this? I tried putting a stiffer spring under the front pilot wheels, but found that it was actually lifting up the front set of drivers. That's not really a long term solution....
Any idea's?
Mike
Meyblic--
Though I doubt it's your tender wheels (if they were reversed, the loco wouldn't run at all, just sit there and sizzle), you might want to check. On brass locos, if you are looking from the back of the tender, the insulated tender wheels are on the right (engineer's) side, the insulated loco drivers on the left (fireman's side). You also might want to check and see if the drawbar is riding too high and occasionally touching the frame, causing a short. There's very little clearance between the bottom of the cab frame and the drawbar of my Sunset models, and you might have to do some adjusting on the up and down tension of the drawbar.
I've got several Sunset models, and they're fine runners and beautifully detailed, but they are also built with VERY close scale tolerances in the details and piping. Check your brake shoe castings and make sure they're not only tight, but not rubbing against the wheel treads on the drivers (especially the insulated side). And also check the brake shoes on the tender trucks, sometimes they can be loose and start riding against the tender wheels. I don't know whether or not your trailing truck has double-insulated wheels (some models do, some don't), but make sure that any piping detailing on the loco body clears the truck mechanism itself. If you have very close tolerances between piping and truck, a dab of epoxy on the pipe where it touches the truck will 'insulate' the problem there.
One thing I'd do is to remove the boiler and run the mechanism with the tender attached. If you have no problems, then there is a contact problem with the motor and the boiler. It could be that the inside of the boiler occasionally touches one of the motor leads. That can be fixed with a little electrical tape on the inside of the boiler right over the motor. Also make sure that the lead to your drawbar connection isn't touching the bottom of the cab floor casting--there's not a lot of room there, but if it is, usually just a little pressure with the flat of a screwdriver on the connector clip will give you enough room. Hope this helps you find the problem.
But as an old brass man, I can tell you that once you get that Sunset running, it'll be like a little Swiss watch. Really nice models, those Sunsets.
check the tender wheels & trucks.
Sounds like one of the trucks or wheel sets are flipped around the wrong way causing the tender to short out, because you aren't having any problems with the loco alone. Check to be sure that all of the insulated wheels are on the same side. You may as well check the loco drivers as well, just to be sure you didn't inadvertantly put something on wrong.
-Dan
Builder of Bowser steam! Railimages Site
I have a beautiful Brass USRA 4-6-2 light pacific imported by Sunset models. Last night I decided to finally take it out of its box and lube her up a little. I removed the running gear from the engine and used some Labelle 106 grease on the gears. I then re-assembled the engine and put her upside down into my foam cradle and using a small power pack and wires, applied power to the drivers and the draw bar. The Can motor purred to life and ran beautifully for almost 30 minutes. I kept adjusting the speed every few minutes as well as the direction (FWD / RVS). I was really impressed how smoothly and quietly she ran.
I then put her, and the tender, on my club layout (DC powered) on a long section of straight track only to find that she wouldn't move 2 feet without shorting out and stalling. Our Dispatch control room has automobile light bulbs wired into the system to light up whenever there is a short on any piece of track. My beautiful little 4-6-2 lit up the board like a pin-ball machine.
I pulled it off the layout and put her back in the cradle upside down and once again she ran perfectly.
Anyone out there have any idea what could be causing the short, especially on straight track? Why does she run perfectly when she's upside down in the cradle, but not right side up on the track?
Michael