N&W 611 Rear cab hop

Lance, I don't know much about Lionel engines, since most of mine are MTH.  I did have success calling Lionel support about the only Lionel engine I purchased new.  I went to their support page and followed the instructions to reset the engine.  That didn't help, so the next thing was to call them.  Someone answered quickly and determined I needed to send it in for warranty repair.  They said they were about 2 weeks behind catching up from when they were closed in the spring.  I received an emailed RMA in two weeks and I shipped it back the week before last.  I hope you get it working!  It is a beautiful engine.

Depending on how good ones vision is. Double check the tires.

If you can get your eyeball down by the railhead , using a flashlight if necessary and watch the "tired " wheel roll across the rail.

You'll see the metal part of the rim rise and fall  in relation to tire thickness indicating an uneven or flat spotted tire.

Any loco that I've had wobbles from tires got better over run time, or after they sat on a shelf on the flanges when not in use.

These engines sit in the Styrofoam on the wheels for weeks or months before purchase flat spotting the tires.

Lance,

  A little more info could help. What is the Lionel product number, are you running the engine using Legacy control, what radius curves is it running on, what brand of track are you running on, does the hop happen on all sections of your layout or only in one place, on curves or straights. The more detail info you can provide will help the forum members try to solve your problem. Also take a video of the engine showing the cab hop if possible there are instructions how to add a video to your post at the top of the forum section. Good luck solving your issue.

JohnB

I'd first suspect a binding rod.  This will cause the symptoms you are reporting, and there will be no obvious visible reason.

I’ll try and get a video, I’m using Gargraves track with 072 curves but it happens around the whole layout both slow and fast speeds.

You can notice the hop towards the end of the video. Helps if you look at the rear wheels.

Are the traction tires (if any) sitting flat in their grooves?  Do they look lopsided or are they a smooth diameter?

@Bob Delbridge posted:

Are the traction tires (if any) sitting flat in their grooves?  Do they look lopsided or are they a smooth diameter?

Knowing how bad Lionel traction tires are, swap them out for MTH tires.