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I received the new Lionel 2-6-0 Milwaukee Road engine last night from Mr. Muffin. Everything works perfectly, except that the lead/front drive wheel derails at the frog. The pilot wheels go through just fine. I have never had this happen before - all my engines and all my Ross switches have worked flawlessly in the past - and am not sure how to correct it. I'd be grateful for any suggestions.

Thanks in advance,


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  These engines have been made for a while and will probably handle an 031 curve. Still there could be something up with it. I’m guessing you have tried other engines through it.

The only thing I have to offer. Check the pins going through the throwbar that are attached to the diverging rails. I changed out 4 throwbars last year. One was really bad. I guess there was an issue about 10 or more years ago with some. The hole in the throwbar gets elongated over time and allows the rails move back and forth. One may not be far enough over for a drive wheel to pass through and it’s riding up over it. Even if one is tight up against the rail. The other one needs clearance for the wheels to pass.

The ones in question are easy to repair in place. The pin slides up through the bar and through a small hole in the rail. A drop of solder on the pin keeps it in place and from dropping down.

Jim, I had a MTH 30-1667-1 Great Northern 2-8-8-2 USRA Mallet which did the same thing on all my turnouts. I ended up returning it out of frustration.  However, I believe there is not enough "weight" on the front truck which allows the wheels to ride up in the switches. The easy fix to try is to wrap a couple of aquarium plant weights or tape a couple of washers on the truck. If that works you can work out a more permanent fix. The other possibility is the wheels or truck is stiff and will not move freely through the turnout. Running the engine should help break in the wheel sets.  I had that "problem" with the new BigBoy's tender. I needed to break it in to operate through switches without derailing.

One other thing to check is the proper gauge of the wheel set. Although with a front truck set it should be obvious the flanges ride easily between the rails. I had a diesel which had one of the drive wheel slightly out of gauge to the point on flange would ride up on the rails. Once I found the problem, I simply pressed the drive wheel to the proper gauge.

UPDATE  - OOPS totally misread your statement "lead/front drive wheel derails at the frog. The pilot wheels go through just fine"  So its not a front truck issue. In addition to Bob's post. I found I had a couple of steam engines which would rock through a switch and derail in one direction but not others. Speed was also a factor. In my case I did not do a great job laying the lead in track and switches. Diesels ran through fine, but the larger diameter drivers and the longer fixed driver sets of steamers contributed to the rocking. 

Last edited by ScoutingDad

Thank you. I'll try that.

I've been puttering on it since I first posted and discovered that it derails only on the right leg of the wye and not on the left. I also reversed the engine and had it come through the wye in the opposite direction and it works just fine. It seems that the drive wheel drops into the gap between the straight lead and the frog causing the engine to derail.

I did get an idea for Plan B. If necessary, I can have the engine running in the opposite direction of the other trains and that would allow for some interesting operating possibilities. (Oh, the humanity!)  Still, I'd prefer not having to limit my options.

I had this issue with a Lionel Atlantic engine. I agree with Scoutingdad that on some engines it seems the truck is just light, On my Atlantic (and I'm not sure if your engine has this or not) there is a small spring that shold keep the truck planted. I removed the truck and added a second spring (from out of a ball point pen, cut to length and stretched a bit). this provided just a little more pressure to keep the wheels planted. I opted for adding weight but couldn't find a suitable place to put it that didn't interfere with movement. just my 2 cents.

@Jim Brenner posted:

Thank you all for your suggestions. I'll post a photo in a little while of the driver wheel and the gap. It seems likely that the lead driver is out of gauge which is something I'll have to check. (How do I do that, by the way?) A bit of styrene will be the next step after that.


Get a digital caliper. Got mine at HD for about $25.00 The wheel puller is from Timko's Repair Depot.

IIRC proper gauge is 22-24mm?

2022-03-19 15.39.00


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  • 2022-03-19 15.39.00

This probably isn’t the issue. But I’ll throw it out there. Are the traction tires on the front axle of these ?  Looks like they are in the pics. . That could explain that it backs through the switch fine. Going forward when it’s the lead driver if the tire isn’t seated well enough it maybe lifting the engine up a bit. The previous run had issues with the tires and a lot of users opted for using MTH tires that fit down in the groove better.  Still hard to believe with the wide rims and good size flanges there could be an issue.

If you do found them out of gauge. At least on these they aren’t captured. Remove the rods and a plate and they drop out.

Jim, what does the lead in track look like. The front drivers are already off the rails before it gets into the middle of the Y.   

Is there any play -side to side - with the front and back drivers on a straight section? I assume the middle has no flange. I was trying to run an engine with scale wheels on a section of curved Ross track, there just was not enough play to allow the wheels to run with the track, so the front wheel set just rode up out of the track and always toward the outer portion of the curve.     

Can you get a photo as the lead driver is entering the points and then partway through? Its probably lifting somewhere within the distance of the point. Just move it by hand.

As an aside, I never really thought much about how a fixed wheel set goes around a curve since the wheels must rotate at the same velocity. In order to make a turn the inner wheel must rotate at a slower velocity than the outer wheels. This link explains how trains are able to turn curves by using a taper or semi-conical section on the wheel profile.  Turning a curve

Thanks again, everyone, for all of your help.

Here's a series of pictures that show the trouble spot: the lead into the wye, the gap between the straight lead and the frog, the engine approaching the trouble spot. (Alexa. Play ominous music). The 4th photo shows the pilot trucks past the frog and the drive wheels almost there. The next photo shows the lead driver in the gap and the final photo shows the driver off the rails.

I have not yet had a chance to do any measuring as I can't seem to find my micrometer to measure the wheel gauge.



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I would not think it’s a driver wheel out of gauge since it is OK in the other direction. There are just some Ross switches that give certain engines trouble going through. I think your only solution is to run the engine in the other direction since you’ve said it does that trouble free. Out of my 36 Ross switches and many engines I’ve only had one engine not liking an 11 degree cross track. I’m pretty sure it was the original 2-6-0 Canadian Pacific. I sold it cause I had no fix.

Is that area where the y is perfectly level/ flat? It looks bit odd like a grade change, unless it's just the angle of the photo.

It also looks like there are some gaps and/or misalignment on the left side of the diverging y.

The front driver is climbing out of the frog ,and at that point. The only other flanged driver is at the rear of the loco. So the second and third flangless drivers follow suit.

If your trackage is nice and level.  This may just be the perfect match of unfortunate circumstances the way the wheels line up when going through the turnout.

Sorry you're having trouble.  Here are my thoughts:

(1) Put a 4" spirit level across the wye switch from left to right.  If the train is leaning downhill to its left at all, that might cause this problem.

(2) Is there any chance that the wood strips you added between the rails to make your grade crossing are pinching the rearmost flanged wheels, which in turn limits the ability of the front drivers to follow the curve?

(3) Does this loco have a tether, infrared wiring, or any kind of special drawbar that prevents the rear of the loco from swiveling as needed?

(4) Last thought re: gauging, etc.:  All 3-rail locos have side to side play in the axles, so that they can negotiate sharp curves.  But that's limited somewhat by one-piece side rods.  (I've found that on MTH locomotives especially, there is so little play in the drive rods, they prefer curves one size larger than they are rated for on the box.)  Despite only having six driving wheels, these Moguls have a LONG wheelbase.  When your loco is on the problem switch, is there any slack in the connecting rods, or are they bound tight?

I think these locos have a "bottom plate" retaining the wheels and axles.  So if the front wheelset is out of gauge you remove it from the loco to regauge it.  Heck, you can (and probably should) order a replacement wheelset from Lionel.  It might be gauged correctly, and it's probably good to get a spare while parts are available.

My $.02.  Good luck and if you solve it, please post back with the solution!

Here is another 2 cents.  It looks like the engine would like to go straight even though the pilot wheels make it through the switch.  Since there is no rim on the middle driver the engine tries to continue in that straight direction and the center driver just slips off the rail  and then the derailment.  Other than narrowing the gap so that the front driver is forced to the right don't really see a solution other than putting rims on the center drivers.

Yet another 2 cents.  I am not sure what you call that short piece of track across from the frog that keeps the outside flanged driver on the rail but the gap appears to be wider than the left direction of the switch.  It probably makes no difference on your other engines but on this little 2-6-0 it might be just enough to allow the inside driver to catch the frog.

Last edited by Bill DeBrooke

One more thought... I couldn't find an exploded diagram for these on  But a graphic in the owners manual and your photos suggest a few things:

(1) The wheels and axles ARE removable, retained by a "bottom plate."  This is the right way to design a model steam loco.

(2) Traction tires are on the FRONT axle.  This is unusual.  (Note, rubber tires limit the ability of wheels to skid, and slide from side to side.)

(3) The worm wheel is on the center axle.  This is a good thing, see below.

If you are comfortable working on your brand-new locomotive, why not swap the wheelset with rubber tires to the rear of the loco?  If this were my train, I would make this swap in a heartbeat, it's easy enough to put them back.  You could even order another smooth wheelset from Lionel, and eliminate the rubber tires altogether.  If there's room, adding a little weight inside the smokebox would improve tracking AND restore some of the pulling power you'll lose by ditching the tires.

Last edited by Ted S

Jim,  I was thinking about what @Ted S suggested about the traction tires on the front driver. You may be able to test this theory by turning the engine around and running the tender through the switch first. If the "back" driver moves through fine and the "lead" follows with no problems, you know how the fix the problem. You could remove the traction tires, but you lose a lot of pulling power. As mentioned previously a narrower tire which sits lower may help.

I have a ROSS  72 wye in a box somewhere, I do not remember the rails not matching up perfectly as seems to show in your photo. If I can find I'll post and we can compare. 

Following on an earlier comment, some of the difference between 3 rail and 2 rail is the removal of flanges in between lead and end drivers of a drive train. This allows the engines to run on far tighter curves than would be possible with flanges on all wheels.   

More thoughts...

First, NICE PHOTOS!!...especially the 6-photo sequence.

Second,  I like the idea of swapping the front and rear drivers if identical/possible.

Third, If the driver swap doesn't work...or can't be done for some reason...I like trying to make the guard rail do a better job of...guarding..., preventing the front driver pair to shift too far left.   It's not a permanent solution, but I think I'd cut a rail-height strip of black electrical tape and apply it to the outside (right side) of the guard rail, narrowing the gap.  Maybe a second layered strip of tape.  If that seems to be directionally correct, then...

Fourth,  contact Steve Brenneisen at Ross Custom and see if he ( or his #1 team) can advise how to make a more permanent solution to the guard rail's effectiveness...or if he happens to see/have another potential issue/solution.  The Ross folks are the best when called upon to render an opinion or offer a solution with their excellent products!

It's too bad that the pilot truck, in this case, isn't helping to lead the engine the 1:1 design would've done.  However, trying to get the 1:48 pilot truck to do that in some manner would probably lead to other problems.l  C'est la choo-choo!

By all means, however, if you achieve a reliable solution, be sure to let us know what you did.


Last edited by dkdkrd

Let me weigh in here.  I agree that the photos are a tremendous help.  The thick Lionel traction tires have effectively reduced the depth of the flanges on the front driver set.  Ross switches are built with the guard rails not as tall as the running rails.  The combination of thick tires and low guard rail means that the guard rail opposite the frog is not retaining the back of the flange on the engineer's side.  The fact that the engine runs through just fine in the reverse direction supports this as the cause.

Either swapping the front and rear driver sets or tossing the thick Lionel tires and replacing them with thinner MTH tires should fix the problem.

Sorry for not responding sooner. Granddad duty (Blue and Gold Banquet, Coach Pitch, etc.) called.

Anyway, thank you all for your ideas and suggestion. You've given me a lot of options and I very much appreciate each and every one of them. Once I verify that the wheels are in gauge and the wye is level, I will try the simplest/easiest suggestions first. I will let you know which one works. Think happy thoughts.

Thanks again,


Sorry for the silence ...

Again, thank you all for your suggestions and recommendations. It turns out that the traction tires were the culprits. I backed the engine through the wye with the tires on and had no mishaps. Based on that, I took the traction tires off and ran the engine through in both directions and it went through with no problem. I think will probably leave the traction tires off for now. My original intent was to use the engine to pull a local consist of a combine and one or two cars and the bare wheels can handle that. I don't plan to pull much more than a few cars and, if I decide to use the engine for something else, I can always swap drivers.

Thanks and a tip o'the hat to Bob Bartizek.


@Jim Brenner posted:

Just for grins, I thought I'd post a picture of the traction tire that caused the problem on the wye.  I was surprised at how chewed up the tire was. There certainly is a big difference between MTH and Lionel tire thickness. Thanks to everyone and a tip o' the hat to Gunrunner John.



WOW! Gonna save this thread for future reference.

Glad you solved the problem Jim.

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