Front truck lifting up on curve


T

tmiller

Guest
Hey guys,

I hope someone has some insight as to my problem. I recently replaced all my Bachmann EZ Track with Atlas code 100, and Peco switches. 18" sectional track was used for the mainline curves, and flex track for the rest. I have a 4-6-2 K4 and a SD70 diesel that work fine around the layout in all directions.

My problem loco is a Bachmann 2-10-2 steam. The front truck is not spring loaded, as some are. Wheels are in guage. The loco seems to run around the layout without any problems, with the exception of one curve. Although the curve in question is slightly smaller than 18", the loco navigates through it without fail going into the right-hand curve. The direction in question, is a left hand curve coming out of a left hand turnout. About 4 inches from the turnout, the front truck lifts up from the inside rail, and does so for another 6-8", before settling down.

From what I have read, there are several isuues to look at: level the track, check the gauge of the front wheels, and the rails. I have shimmed the track to level. Now, being new to laying track, I did find that my track nails were pulling the rails in. I releived the nails and the rails did straighten out somewhat. But still a probem. Using my NMRA guage, I checked the rail spacing. It might be slightly out of gauge, meaning the rails are too close together. The gauge slides between the rails, but is a little tight, hearing scraping, so I assume they are slightly out of guage. Not knowing how to correct this issue, especially on a curve, I have tried to lightly file the inside rail, hoping to increase the spacing of the rails. As of right now the filing hasn't seemed to have fixed anything. The guage still scrapes slightly. I don't know what else to do to correct this situation, other than possibly replace this 18" piece of track.

I am at a real loss as to what else I can do. I hope someone has some ideas. Greatly appreciated. Thanks.

Ted
 
I believe you've answered your own question: " Although the curve in question is slightly smaller than 18""

What I've found is that the 10 wheelers that will do 18" radius curves will NOT tolerate ANYTHING less than the full 18".
I just had to replace a 18" curve that was made with flex track that had been in place for 25 years.
My 2-10-0 would not go around it. I put some atlas track on top of the curve and found that most of it was good but one small part was just under the 18".
Replaced it with the atlas track and it's been perfect ever since, no more derailments.

That would be my guess..
 
Relay the curve. Honestly, just figure out how to fit a slightly wider curve there, including relaying the approaches, or tangents, on either end of it. It will take two or three hours at most, even if you have to repair scenery around the tracks.
 
What is your benchwork size? Could you post a track plan? Is it possible to add some plywood pieces to the ends so that you can get 24" curves?
 
Okay guys, here is what I have determined. In looking at the curve, and matching it up with some sectional track, it appears to be closer to a 15" curve than what I previously thought. See the picture:

View attachment 42545

The upper curve, between the two turnouts is the problem. The problem area is between the right arrow and the left black mark. It would be impossible to change the radius between the two turnouts because the left hand turnout on the right dictates where the track will lay coming out straight from the turnout. All turnouts are PECO #6. There is another similar curve off to the left, off the picture. But it is strange that the loco will navigate through the curve off to the left, unseen, (same radius), then navigate the curve in question, but will not navigate coming from the right.

So, for now I simply will run this loco on the mainline only, which does have 18" curves, unless someone has a solution. Guess I will have to stick with locos with lesss than 10 wheels.

Thanks a million guys for all your comments.

Ted
 

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Yikes! Ya I see that. Ok what you do is this. Move that outside track out more, to the right. And also move that switch back away from the tunnel more, about 8" or so. That should give you enough room to smooth out that curve to a larger radius.
 
I have several 4-6-2's that don't seem to mind the smaller radius. I have a 2-8-2 that gets a little "jumpy" under 18". It's tough to run the big dogs sometimes. These guys are a great source of help. Another set of eyes is often the best diagnostic tool available. Experience doesn't hurt either.
 
I would agree that, if possible, move the right-most LH turnout back. However, I seem to see a "kink" in the track between the left-most RH turnout and the divergent track. I wonder if fitting a double-curve turnout in there could help increase the radius of the outmost track.

Another thought: Have you checked the lead truck to see if the wheel that is lifting up off the track is hitting the inside of the cylinder block? I have a kitbashed 4-8-2 Mountain (made from Mantua 4-6-2's and 2-8-2's). There is one curve that is 18" radius that caused a similar thing to happen. I took several sectional pieces of 18" radius, connected them, set the locomotive on it, then, grasping both firmly turned the track and locomotive upside down and examined the lead truck/cylinder block relationship. Lo and behold! the inside front wheel was hitting the front corner of the cylinder block. Out came the Dremel tool and files. I took enough material off the inside front corner of the cylinder on each side to allow the truck a little extra room between the wheel flange and the cylinder when the truck was deflected on the track. No problems after that.

One other point that you touched on...NOT running the ten-coupled locomotive on the outermost route. Real railroads were often troubled by that situation. Their solution was simple...they didn't run such long wheelbase locomotives on such tight radius curves. I have four kitbashed Mantua ten-coupled locos which will run on 18" curves, but to do so, I've used blind flanged wheels on all but the end axles, and shimmed the center drivers up .010" and the flanged drivers down .010" to keep the blind drivers from catching on the inside of the rails coming out of the curves. I also had to remove material from the inside of the cylinders to permit the lead trucks to swing sufficiently.
 
Didn't think about blind flanged drivers, Glad I looked at this again myself. May be the solution to my penchant to large locos and space limitations.
 
I agree, just move that turnout back from the tunnel about 6-12". Just enough to ease that curve. If there's not enough room to move that turnout back some, you may need to change it from a #6 to a #5. If the turnout matches the NMRA standards and RP's a 2-10-2 will have no problem going through it. I know that the brass 2-10-2's I have, have had no problems going through #4's.
 
A couple of posts back "Trailrider" mentions the front truck wheels hitting on the cylinders on the tight curves.
Today I was running my Decapod around and it was doing it's normal random derail on a curve every now and then thing so I watched it closely for a few turns and found that it REALLY does touch the cylinder on an 18" curve. Both cylinders have a tiny mark on the edge where the wheels have been hitting.
I hate to do it but I'm going to take a jewelers file to it and cut the cylinders back a tiny bit right where the marks are just enough so it can't touch.
 
Well, that opened a can of worms. I cleared the cylinders, but now we get a short every now and then on as we start into the curves.
So what I find now is the frame under the front is cut out for the wheels. Clearing the cylinders lets the wheels travel just enough to short out on the frame at the inside of the cutout.
So now I guess it's time for the Dremel to grind out the frame for a little more clearance.

But its running better without the random derails it was doing.
 
decapodwheels2.jpg
decapodwheels1.jpg


Took a bit of work, but I got it. Had to cut out the "wheel well" so to speak all the way over to the screw in the middle on both sides.
I cut some then ran it some and it would mark it where it was hitting. Then I cut more and ran it more till it quit leaving any mark.
Runs around fine now with out any issues.

So for anybody having steam issues on 18" radius, check your cylinders....
 
I have clearly lost my mind. It would never occur to me to run a normal sized 4-6-2, 2-8-2 or 2-10-2 around an 18 inch radius curve. While it may be possible it can't be reliable. Mylargest steam loco is a 2-8-0 and my smallest radius is 22 inches in a "back woods logging" senerio. I'm hoping all works out OK.

Good photography though, it was very easy to see the problem. If you need some 18 inch snap track, let me know, I have lots to spare. Jim
 
It all depends on the engine. I have a 2-8-2 that's been running around flawlessly for 30 years (converted to DCC now). This new 2-10-0 required extensive track work and minor mod to the engine to do it. However it IS advertised as running on 18"r track, says so right on the box. And it would, but the track had to be PERFECT, mine wasn't. The up side to all this is that EVERYTHING else runs way more reliable now.
 
With one exception, the wheels on the lead trucks of my Mantua-based steamers are plastic, so I only had to deal with clearance problems, Clarence (sorry, "Airplane" was playing the other night :rolleyes: ). As to running 10-coupled locos on 18" radius curves, it depends on your sense of aethetics. I only have the tight curves in certain areas of my layout. Where possible, I do have 20-22" radius. But where 18" curves are a necessity, I have them, and the locomotives run fine. Actually, I have more problems mechanically with C-C (six axle) diesels. In some instances, I had to remove the wheels from the center axles on the diesels and some 3-axle trucks on heavyweight passenger cars for reliability on some turnouts. My layout is 32-36" above floor level, so you can't see that the missing wheels are...missing.
 
trailrider said:
... In some instances, I had to remove the wheels from the center axles on the diesels and some 3-axle trucks on heavyweight passenger cars for reliability on some turnouts. My layout is 32-36" above floor level, so you can't see that the missing wheels are...missing.
Click to expand...

Nothing wrong with doing this. I have found over the years, that some "middle" axles on 6 wheel trucks actually cause the truck to rock back and forth onto the outer axles. This has always been in plastic 6 wheelers, but not any of the nylon based trucks like Athearn's and others. In those cases I've either removed the wheels or trashed the trucks, depending on whether or not I had replacements.

As to removing the center axles on diesels, I've never had to, however, I knew some folks down in south Alabama outside of Mobile that did that. The only place that they had room for a layout was in the back of a mid 1960's Ford van. Their layouts biggest curve was 15", but they loved 6 axle diesels. They found that by removing the middle axles on their Athearn BB 6 axle diesels, that they would make the curve.

They didn't care about the aesthetics, they just wanted to run trains. They were young teenagers at the time, and I've lost touch with them over the past 30 years. I don't know if they're still railroading or not, but they were having fun then and that's all that counts.
 
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