I bought an Athearn CP SD40-2 “Beaver” for my grandson at a train show. It was in the box and the seller said it was new. I’ve now discovered that this model was discontinued in 2001 so it is not exactly “new”, although it appears never to have been run. We put it on his Power-Loc track last night and, after having to nudge it a bit, it started to run. However, it keeps derailing. The front truck appears to “bounce” up and down and the front wheels ride up over the rails. The trucks also don’t seem to turn very much, so the engine has a hard time going around curves. My grandson’s other engines don’t have these problems. Is this something that can be fixed by a handyman such as myself? Or, do I need to take it to a train shop for repair or send it in to Athearn to fix?
I love sd40-2, so my engine fleet is mostly athearn sd40-2’s.
My first Question is how big are your curves? I did a check and i saw ther was an 18" radius and a 22’’ radius out there. Now sd40-2’s are three axle engines, they will go around a 22’’ fine but will have a hard time going over a 18" radius track. If you have 18" it might be the problem why its jumping the track on the curves.
Now the bounce i do not know for shure. Do you have the track attached to something or is the track sitting on top of something freely?
The track is nailed to a 4’ x 8’ piece of 5/8" plywood that is covered with green felt.
I think the curves might be 18", but I’m not sure.
My grandson has a Bachmann engine (Conrail #6203) which also has 3 axles on each truck and works fine on the track. I looked this one up on the Internet and found that it is an SD45.
Any suggestions?
Your curves are too sharp. 18"r. curves are not prototypical, and are designed for 4X8 simple layouts.
MOST 3 AXLE trucks dont like sharp 18" curves and ‘Snap’ switches. SOME mfgr’s purposly design more ‘slop’ in their engines to sell to the 'Beginner ’ market.
FIXES: REMOVE the center, axles, or modify to allow more lateral side/side motion (Slop).
BETTER - Run engines using 4 axles; (Save 6 axle engines for 22"r and #4 switches).
The bouncing problem sounds a lot like a cracked gear to me.
Your best bet is going onto Athearn’s web site, and ordering their SD40-2 gear set, and replacing all of them.
Phil
Check the wheel gauge , if they are out of gauge it will derail . I have an SD 40-2 and it derailed on sharper curves but once I regauged the wheel I have not had an issue .
You will need an NMRA gauge and then just push or pull the offending wheel back in gauge.
Like Don said most 3 axle engines are ment to be longer running engines that require larger radious curves.
Skippy,
Start with carknocker’s advice. Check the gauge of all wheels and adjust them to be on the “tight” side to allow more “slop” in negotiating 18" radius turns. You can also remove the shell and check the swing of the trucks. Sometimes there is some flash which limits truck movement. Also, since the unit has been around for awhile, the front truck might be off the bolster.
Tilden
However short-wheelbase 6-axle engines can. I have 2 P2K SD9s, and they run just fine on the smaller radius turns. IDK about athearn’s because I think they use the same frame for everything with a B-B or C-C arrangement.