I bought 3 Athearn engines about a year ago and they slowed down on the curves. So I took them back to my L.H.S. and traded them for another brand. A friend of mine bought 2 the other day and they do the same thing. Are they any thing I can do to fix this. My smallest radis is 15 inches and they slow down on all of them.
Is this running free or pulling a train?? Pulling a train, I would expect them to slow a little as there is more load pulling around a corner. Running free, they may drag slightly but it shouldn't be a huge change. The first thing to do is get some run time on them. It may just be tightness in the universals or drivetrain than needs a little break in time. Set up a loop of 11" radius track and run it on that for 10-15 minutes. I would bet after that the slowdown will disappear on your layout with 15" radius.
What sorts of locos are you running. I notice that six axle diesels tend to this more than four axles, and if you think about the geometry of the three-axle trucks going through the turns this isn't that hard to figure out that that middle axle of wheels on each truck is basically "pushing" in on the inner part of the curve as the first and third axles are forced into the outside of the turn, thus pushing the loco trucks each outward on the turn. This is more pronounced in tight curves, which is why a lot of us like broad curves on our layouts. Similarly, really long steam locos, with lots of drivers, tend to get hung up on turns more than, say, 0-4-0's. Adam
The other issue that Athearn had was the QA on the truck gears. They weren't that smooth, could be noisy and as you found could cause the engine to slow down on curves. The fix that I read about and have done to a bunch of these engines is take the trucks out of the engine and using Pearl Drops denture tooth paste. Apply to the gears liberally and begin to run the truck back and forth working in the pearl drops, adding a little now and again. The article said to do it 100 times but I never count. I just sit down infront of the TV and doing it for 15-20 minutes. Now what this does is pearl drops is a polishing tooth paste so there are very fine particles in it which works into the gears, polishes them, and rapidly breaks them in. Once you are done working everything in strip the truck completely down and wash all the parts making sure to get all the pearl drops out of everything. Let dry, re-assemble and lube. I found before doing this if I put the truck on a 2% grade it wouldn't move, but after the pearl drops, put it back on and it would roll freely down the grade and around the curve at the bottom of the grade.
I have done the "polishing" thing, and it does work very well, because it does knock off all the very fine tooling sharp edges on new gears. However, I have never used tooth polish as an abrasive. I have used automotive valve polishing compound, or an automotive finish polishing compound. The tooth polish may work out nicer for clean up though being water solvable, AND the bonus is your train will look, smell, and feel minty fresh!!! :tb-cool:
Unless I missed it, nobody mentioned checking the wheels to see if they're in gauge. That oughta be first on the checklist.
