I decided I would like sound in a consist pair of locos so I bought a Gold and a Silver. I added a ESU non sound decoder to the Silver. My layout is all Kato Unitrack with a single crossover. It has been known to cause some trouble but not moving straight thru. Both of the locos pick the point with the rear trucks and derail heading straight thru every time. After shell removal derailment is some improved giving me to suspect binding of the truck. Has anyone else had this problem and was successful in fixing it?
You might want to start by checking the wheel gauge on your units. I use an NMRA gauge like the one seen here. Also, are the trucks hard-wired to the chassis or by contact strips? I have a newer pair of Atlas SD-35s that are factory hard-wired and the trucks are unforgiving of any track irregularity, not wanting to rock from side to side. The wire chosen by Atlas seems to be of an unnecessarily heavy gauge, but perhaps I'm wrong. They demand perfect track. I use them as the "acid test" for my trackwork.
Check your truck sideframes for a little nub on the bottom that protrudes downward. I have a silver that has this nub on both trucks and I've heard a LOT of other folks have it on theirs, too. Guessing it's a chip in the manufacturing mold. Just snip it off and see if that helps? Cheers -Mike
Seems so. So long to the virtually flawless contact strip design we've enjoyed for a few decades until now.
Not only do new Atlas locos have hardwired trucks, they also now have a pre-wired harness that only accepts a specific decoder.........no more choices unless you want to rewire.
IKR!!! What's up with these manufactures??? For years we all complained about hard wired trucks. They came up with the contact strip idea. It has been working great....easy to work on. The whole nine yards ! Then someone has a flashback memory and dug out the old blueprints for the wired trucks and well...you know the rest of the story...
This, 100% Most newer Atlas locos I've bought (even used) had the wheels out of gauge, causing derailments randomly and shorts on turnouts. The nmra gauge is pricey, but it saves a ton of time troubleshooting. Sent from my Pixel 8 using Tapatalk
For those that haven't seen it, these are the truck nubs referenced earlier. Sometimes they're only on one truck, mine has them on both: Cheers -Mike
I trimmed the bottom of the trucks and cut the tabs off the wheel pick-ups. The tabs contact and restrict the truck movement and with the pick-up wires, no longer have a use. This worked well without the shell. Replacing the shell brings back the problem.
I have four of the new SD9's and one has a wicked click in one truck assembly. It will actually lock up leaving the assembly with only the outer axle on the rails, but not turning. They seem to track fine and will look closer for the nub mentioned. I am disappointed with the new Atlas so far. I do like the new design ideas, but if decoders keep failing and tracking issues persist I will look elsewhere to spend my hard earned money. Also, I set my 20(?) year old SD7 next to a new SD9 to compare and don't see any improvements on the detail front.
I compared the gauge of an older SD7/9 and found that the new ones are .011 wider. I was able to press them to match and have eliminated the problem on one of the two. Still working on the other. Thanks Hardcoaler!
I am not at all surprised. They have beaten the GP7 and PhII GP9 shells into oblivion. Running an re-running them, without releasing any newer shells. It's long past time for a later phase.....
