"Waddle" in tracking of 2-6-0 Eureka and Palisades.

[wagnera361]

is the "waddle" of the classic Eureka and Palisades 2-6-0 a feature? or an alignment issue. Since the true drive is a worm gear on the center line of the engine, the opportunity to induce "waddle" might arise from the valve gear or side rod lubrication (all checked), some imbalance of the wheel/side rod counterweights (unlikely), drive wheel misalignment? The waddle is synchronous with the wheel revolution. Does anyone have any thoughts? Thanks.
Ned Wagner

[veetwelve]

With the information you've given, it sounds like a slightly bent drive axle.
Best of luck,
Jay

[Greg Elmassian]

are you talking back and forth side to side, like closer and further to a rail

or

waddling like a tipsy person tilting left and right as it goes down the track

or

basically turning left and right as it goes down a straight track?

Greg

[Fred2179]

The waddle is synchronous with the wheel revolution.

If you look at how the wheels are secured to the axles, it is quite possible that one wheel is not perfectly at 90 deg to the axle. The nylon bush does allow a bit of latitude in the fitting.

Put the loco upside down [careful with that whistle casting - use a lump of styrofoam to support the cab roof,] and apply power. You will probably see one (or more!) wheel wobbling as it rotates. Grab a felt-tip pen and use it to mark where the wobble is greatest. (Hold it close to the wheel and let the wheel touch it as it wobbles.)
 
Once you figure out which wheel is wobbling, you can pop off the center screw cover in the middle of the wheel, and tighten the screw, or remove the screw and push the wheel into alignment, or just try to rock the wheel into alignment.

[wagnera361]

Thanks. I'm a cautious newbie, and will begin a cautious exploration. The waddle is a side to side oscillation in synch with wheel (piston) cycle. I've not run it on actual track yet (mine's only up at Christmas time) but have observed it on rolling rails.
Ned Wagner

[Stokerman]

Likely, much of the advice and suggestions you have already received will lead you to the problem and the cure. However, I simply wish to point out that real locomotives quite often are seen to "wander" side to side between the rails, especially ones with shorter wheel-bases on older, less well maintained track that has sags and humps on one rail or the other, or both.

[wagnera361]

Thanks to all for thoughtful responses. I suspect that "Stokerman"s" comment is applicable. the "waddle" is side to side, moving the point of the pilot less than 1/8" side to side when on rolling rails. The waddle is almost not noticeable on actual rails. If the waddle becomes an issue when running on rails, I will explore analysis of how much and which wheel may be out of alignment.

[Greg Elmassian]

so the question I asked and you only now answered is the second one....

that can be a factor of wheel contour, rail gauge, wheel gauge, etc.

Note your rollers do not have a contour like a railhead...  wandering side to side on rollers is normal on them.

Also, get a pair of vernier calipers and see what your gauge really is, and also measure the back to back dimension on the wheels.

Greg

are you talking back and forth side to side, like closer and further to a rail

or

waddling like a tipsy person tilting left and right as it goes down the track

or

basically turning left and right as it goes down a straight track?

Greg