# Six-wheel truck on uneven track



## mikek (Dec 29, 2013)

I'm constructing a Hobbytown B-unit with six-wheel trucks. I mounted NWSL blunt-end wheelsets, and they do fine until encountering a rise in the tracks. My test track is a circle, so when the truck first clears the rise the leading wheelset derails. 
My question is: can the derailing be engineered out of the truck, or are rises taboo in track? I use Bachmann E-Z-Track for my test circle, so fastening it down permantely is not possible, it's on a coffee table. I probably can work the rise out by bending the track down to eliminate the bend. Earlier I had the track taped down to avoid this problem, removed it because it looked trashy.


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## wvgca (Jan 21, 2013)

if other six wheel locos derail also, either mounting to a piece of 1/2" plywood, or bending the twisted section should fix that .. if that b unit is the only loco that derails there may be some binding or lack of clearance somewhere..


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## Cycleops (Dec 6, 2014)

If I understand you correctly what you saying is that the track is undulating because it is not held down and this is causing the derailing where it rides up. If this is the case you could try using some clear double sided tape underneath which would have little visual impact.


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## broox (Apr 13, 2012)

I've used blutac under parts that had a bit of unwanted flex, maybe that will help? Colour it dark brown/black to blend with the ties, should be a go-er.

The kids colour my blutac with texta when they have little art & craft / construction sessions, doesn't look too terrible... 

A more permanent solution may be coloured silicone (I think you guys call it caulk). That works a treat!


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## D&J Railroad (Oct 4, 2013)

Ya have to keep in mind, trains are not off road vehicles. They require smooth track with mild transitions in curves and grade changes. As for the track not being fastened down, you are going to continue to have problems like this untill you either get lucky with the way you have your track laid on the floor or you secure it to an operating surface.


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## mikek (Dec 29, 2013)

Thanks for the help. My other six-wheelers weigh more than the B-unit, so maybe they push the track flat. I'll check with my lightest other six-wheeler, to see if my B-unit is too rigid or such.
I mounted the truck on a piece of plastic, pivoted at the middle wheel. It does fine everywhere but the highest bump. I have the piece of plastic filed to a taper so the truck can rock front to back a bit.


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## DonR (Oct 18, 2012)

As mentioned, weight can be a factor in truck tracking. It appears the
car is cast metal which should provide ample weight, but is it as heavy
as your 3 axle locos that do track correctly? You can try putting weight
inside to see if that helps even on rough track.

Don


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## mikek (Dec 29, 2013)

Thanks, Don. I added weight earlier to the B-unit, but my little Athearn Geep was spinning it's wheels trying to pull it, so I removed the weight. I'll try with a different loco...I was surprised to see an 8-wheel drive loco spin it's wheels, but it doesn't have tires, so it's shiny wheels on shiny track. I wiped the track, brought up some black marks on the tissue, followed up with an alcohol swab, which helped somewhat. I've checked the wheels, they seem to roll freely enough, the unit will coast a bit when pushed by hand.
This setup does not have bearings, the blunt axles roll in drilled holes in the sideframes.


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## MtRR75 (Nov 27, 2013)

Trucks need to be able to rock back and forth and side to side -- just a little -- in order to stay on track, since track is never perfect. On your B unit, check and make sure that the screw holding the truck on allows for a little motion in both directions. If the screw is too tight, you will surely get derailments.

Also, in you picture, if that is your track set-up at the top of the pic, the two rails are out of alignment. That will likely cause derailments.


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## DonR (Oct 18, 2012)

Those metal wheels should let that unit glide down the track.
An Athearn GP should have no difficulty pulling it. I have Bachmann
GPs also without tires. They can pull 10 or 15 cans without
slipping. Just looking
at the length of those trucks compared to the radius of
the bit of track shown above them makes me wonder if
the wheel flanges are binding against the tight radius rails. Do you
find that pushing it by hand around the radius is difficult? That could
also result in the derailing.

Don


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## CTValleyRR (Jul 26, 2014)

What radius is your circle? Those long trucks are going to be pushing hard against the outside rail in anything less than a 24" radius. If 18", I wouldn't be surprised if they're binding up like Don suggests.

In any case, a long truck like that on a tight curve will derail at the slightest bump or misalignment in track. 

Conceptually, the fix is extremely easy: use wider radius curves. Unfortunately, that isn't always so easy to put into practice.


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## D&J Railroad (Oct 4, 2013)

Look at post 6, I can see the track isn't connected with a joiner. If that's an example of the rest of your test track, then you have more problems just waiting for you. I'm not sure if that's how the ez track is supposed to work, I.e. just relying on plastic clips under the ballast to hold things together, but if it is, I'm inclined to think they would post a disclaimer on the box it came in stating that the track is not really intended to run trains on. It's just for looks.


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## mikek (Dec 29, 2013)

Yes, you're both right. Luckily, the track in the pic is not my test track, just some on my workbench. I'll have to fix that alignment.
I have put some side to side freedom in the trucks to help the wheels make turns, may make more. If I had the right equipment, I'd put in bushings, the drilled holes in the sideframes are not perfect. I think I'll also file the taper on the plastic truck mount a bit more. I check trucks for freedom by lifting each wheel to see if it can rock up leaving the truck still touching the track. I've had problems in that area, know it's important for trucks to have freedom.
On the power trucks, Hobbytown recommends filing the bearing housing so the center wheel can float up over bumps, keeping both end wheels always on the track. I may do that to this set of sideframes. Basically, it takes the center wheel out of any supporting role, it's just there for the looks.


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## Old_Hobo (Feb 20, 2014)

In no world would I pull a 6 axle B unit with a 4 axle geep anyway.....don't think it was done much.....but that's just me.....


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## D&J Railroad (Oct 4, 2013)

You can check the wheel levels on the truck by putting the truck on a mirror. Look at it from down low and the variances will be very obvious.


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## mikek (Dec 29, 2013)

Old_Hobo said:


> In no world would I pull a 6 axle B unit with a 4 axle geep anyway.....don't think it was done much.....but that's just me.....


I grabbed the geep off the shelf 'cause it had matching couplers and was easy to carry around without concern about breaking it. Just using it as a test tug. I sold the PA1 that goes with the B-unit, it went to Switzerland. Once I get this unit rolling perfectly I'll notify the buyer that it is available. It's probably not a PA-B unit, probably an F-B unit, it's kinda long, as long as an F-unit. The PA-1 unit was shorter...
Actually, using this geep as a tug will tell me when I get the B-unit really free and smooth, it will stop spinning its wheels on startup. Maybe I can put in a sand dome???


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## Old_Hobo (Feb 20, 2014)

PA's are longer than F units, and F units didn't have 3 axle trucks......could be an EMD 'E' unit.....

We would know what it is for sure, with a side shot pic......


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## mikek (Dec 29, 2013)

Thanks, Old Hobo, you're right. I get my 'E's, 'F's, and 'P's all mixed up, will have to get a poster or something to keep me straight. Here's a pic of my other 'B' unit, it rolls fine. I checked it's wheels, they can move more side to side than the one I'm working on. I'll loosen things up. I'm curious as to whether it makes any difference if the truck pivots on the center axle or off-center like this other one. I moved the pivot hoping it would help things, can move it back if it's important.


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## broox (Apr 13, 2012)

Grab a NRMA track gauge and a pair of pliers. Maybe the track is slightly out of guage and needs some adjustment, probably more noticable at the joins.

Could also check that the wheels of the locos are in spec too.


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## CTValleyRR (Jul 26, 2014)

Mike -- the issue with the long trucks isn't where they pivot. If you imagine the truck as a long, fixed rectangle, the question is, will that rectangle move along curved track in such a way that the wheels remain inside the curve of the rails. On an 18" radius, I'm betting the answer is no. My PA will not run on 18" curves, nor will my GE E33. Both locos have long 6 wheel trucks. 

Modifying the trucks won't help, unless what you mean is modifying them so the wheels are free to slide side to side. Likewise, allowing the center wheel to pop up isn't a great solution either, because it will introduce up and down motion to the truck, which may well derail the other wheels. The flange might also get stuck outside the gauge, causing further binding. What might work is using blind wheels (i.e., without flanges) on the center wheels, allowing them to freely slide over the rails. Some steam loco manufacturers use this trick.


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## mikek (Dec 29, 2013)

That's a lot of good information, CT. I think I'll run both B-units behind the same loco and compare their actions. Then I'll try to make improvements in the one that derails. I may just correct the track and leave well enough alone. I image most serious track is down flat, and such problems would not appear. True also, about tight turns. 24" radius is as tight as many of my units will navigate. My DD40s are real tight on it, I had to insulate frames to keep trucks from shorting out.


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## wvgca (Jan 21, 2013)

as far as i remember the hobbytown trucks were a little different than most, similar in some ways to the old athaern metal sideframe trucks that also had blunt axle ends that were supported by the side frames .. if you take the two screws out of the top of the powered truck that should disconnect the worm drive, and then you might be able to hand push the chassis on the track and see how free rolling it is, and find possible needed adjustments ... ?? maybe ??


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## mikek (Dec 29, 2013)

I taped the track down, but the B-unit would still have a wheel out of place after a circuit. Upon closer examination, I find bumps at many joints.
When I built this test track out of broken Bachmann E-Z-Track I clamped and glued the sections together, since the plastic joiners were all broken off. This has created the problem, the technique made a rise at the joint. Regular E-Z-Track can relax at the joint and settle down flat.
I'm going to get a nice flat piece of 3/4" plywood the size of my circle (48") and screw the track down right at these offending joints. That should fix 'em.


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## Old_Hobo (Feb 20, 2014)

mikek said:


> When I built this test track out of broken Bachmann E-Z-Track


Say no more.....problem identified.....


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## broox (Apr 13, 2012)

Have you ran the B Unit without it being attached to any other rolling stock? if not, could the coupler "pull" between units on the tight radius be helping it to derail?


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## dagnarble (Mar 23, 2010)

The track above your picture seems a little out of alignment. You probably checked the derailing spot. Just saying


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## mikek (Dec 29, 2013)

Brooks, the wheel comes off even when rolling by hand. Dagnarble, the pic is not the track I'm using, just some on my workbench.


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## mikek (Dec 29, 2013)

I put bushings in the sideframes to smooth out the rolling for the wheelsets and made a table top out of an old door to mount the track on. The circle measured 38",not 48" as I previously mentioned. Now I understand why my DD40s are so tight on it.
I'll take pictures when it's done. Right now I'm breaking in the bushings, pulling the B-unit around the current track with a 'Cow' switcher by Athearn, the Geep just doesn't have traction. I'll sort out the Geep later, maybe add weight to it inside somewhere. It is a bit light for a loco.


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## DonR (Oct 18, 2012)

I can't quit thinking about the length of those trucks.

If you can remove one easily, put it on the track without the
body. You can then see how it's wheels relate to the
curvature of the track. There is the possibility that
the center inside wheel is being hard pressed against the
rail and binding.

Don


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## CTValleyRR (Jul 26, 2014)

DonR said:


> I can't quit thinking about the length of those trucks.
> 
> If you can remove one easily, put it on the track without the
> body. You can then see how it's wheels relate to the
> ...


I agree. That's where I was going in Post #20 above.

At around 3" length, those trucks are a beast.


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## mikek (Dec 29, 2013)

That's a good point, Don and CT. I'll remove the trucks and do that test. My new table should be done today, I'll have flatter track for testing, and can improve the power contact, too.


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