Turnout issue


KB02

KB02

Well-Known Member
I'm having a bit of a problem with a turn out that is somewhat difficult to describe. This is a left handed Atlas Snap Switch turnout (No, that's not the problem... well.. not the problem I am writing about, anyway...)


When my 4-6-4 Hudson takes the diverging route, the last set of drivers tends to get pulled up onto the inner rail/check rail just before the frog. The first two drivers don't have this problem, just the last set. Of course, not only does this sometimes cause derailments, but also the wheels hitting the rail causes a short.


Note the second driver being lifted high above the rail and not making contact.


It's almost like the check rail on the far side is just pulling the wheels too far over so they have no choice but the drive up onto the opposite check rail. I have checked everything for gauge (loco and track), and aside from the tracks on the diverging route being a little loose, everything looks good. I am tempted to trim off the plastic check rail on the far side to see if this cures the issue, but I'm worried that it might cause issues with other locos (The hudson is the only one that does this little dancing trick).

What do you all think?
 
First., what is the brand of the locomotive? I see that the second driver(s) are flanged. I wonder if the flange on the far (left) second driver is being pulled over by the diverging guard rail, causing the rear drivers to be pulled over as shown. I don't think I would mess with the turnout. It might be a pain to do, but if it were mine, I would remove the flanges on the center set of drivers. Except for some very old, small Roundhouse locos, which I don't run much anyway, all my steamers are Mantuas, which came with the middle drivers with blind (flangeless) drivers. I even have the center drivers on my kitbashed 2-10-2's, 2-10-4's and a 4-8-4 and a 4-8-2 blind. No trouble running them through Atlas Snap-switches or #4 turnouts of other brands. Of course, turning off the flanges is going to be a bit of a hassle. You'd have to remove one wheel, chuck the bare axle up in a drillpress or somesuch, and take a file to the flange. Then you'd have to reinstall the wheel, remove the other one and repeat the process. You'd also have to re-quarter the wheels, and probably requarter the other drivers to insure against binds. NWSL, now back in business, used to have a wheel puller and a quartering jig. Not sure if they still sell them. Not sure what else you could do...
 
If you have a way to video the loco going through the switch at a slow speed, that could proof helpful, especially if you could do both sides. If you could then slow the video down, you would probably not have any problem seeing what is happening and figuring out a cure. Is this the only loco doing this and is it a recent occurrence?
 
Thanks, guys.

It's the only loco I have that does this, yes. It's an early 80's Rivarossi. It's also the only steamer on my layout (The excursion train of the Whistlestop RR). The vast majority of my fleet are 4-Axle diesels and they don't seem to have much issue with this turnout.

I hadn't thought it could be the middle drivers causing the problem. I'll have to try to the video trick and see what that turns up.
 
Is that a #4 snap switch?
Check the wheel gauge on the drivers, see if they are too narrow.

I have a brand new #4 code 83 and very old #4 (Atlas brand.)
I'll dig out my pizza cutter Rivarossi and try to duplicate the problem'.

UPDATE
My 4-6-4 does the same thing.
I think due to the long wheelbase, driver 1 to driver 3, the frame is being forced too hard over allowing the rear driver to dig into the side of the area circled in red. As an aside, my flanges are not as tall as I modified my loco to run on code 83 rail.

modified pic.jpg
 
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Oh good, it's not just me. :D:D;)
Yeah, after trying to video trick (nothing to post... sorry), it does look like the middle driver that starts the chain reaction. I need to replace the traction bands on this loco, so maybe I'll get brave and file down the flanges when I do that.
 
KB02 said:
so maybe I'll get brave and file down the flanges when I do that.
Click to expand...
Just to add a little more mystery into the situation,,, if your trailing trucks don't have enough side to side 'travel', they may be keeping the drivers from tracking properly. If not an electrical contact situation (probably not), try removing the trailing trucks and see if it resolves the problem...(just an idea that doesn't involve major surgery)
 
Trailing trucks have tons of travel (sometimes too much) and are basically free floating. While I doubt they have anything to do with it, I'l take a look.
 
KB02 said:
Oh good, it's not just me. :D:D;)
Yeah, after trying to video trick (nothing to post... sorry), it does look like the middle driver that starts the chain reaction. I need to replace the traction bands on this loco, so maybe I'll get brave and file down the flanges when I do that.
Click to expand...

Filing down flanges is tricky.
These are nickle plated brass wheels. SO you end up with a two tone color.
And you need to file down in a perfect circle, not leaving any burrs, so, it a machine and polish job, not just taking a flat file to them.
The flange will need to be narrowed to match the NMRA profile.
 
Good point on the bi-metal composition. Guess I'll have to decide if that would bother me or not.
 
Personally, I think the radius through the switch is too sharp or the track beyond the switch has a curve too sharp or a kink. If you look closely the 2nd driver is completely off the rails. To me that seems like a curve is too sharp and the pilot truck is pulling the drivers too far over because the curve is too sharp. Snap switches are 18" radius or less. Waaaaay tight for a larger steam engine.
 
I was going to say the very same thing as dave1905 before I even got to it ! The #4 is too obtuse for the rigid frame 8 drivers..I don't think even a 1:1 scale RR would attempt this with anything but a small switcher..I'd say either forget running the Hudson through this switch, or reconfigure trackwork to replace it with a more acute one such as a #6, or higher (even the 6 might be too tight, too). And by all means, don't turn down the flanges to correct it. It will be same situ whether deep or shallow flanges..
 
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Sadly, the majority of the turnouts on my layout (the original 4x8 section) are all snap switches and the curves are all 18"r. That's actually why I run the Hudson and not a bigger steamer - because it can handle the 18" turns. AND, this is the only turnout where it has this problem.

The leading trucks, like the trailing truck, have tons of travel on this loco. They're not the problem. The more I have thought about turning down the flanges, the less I like the idea anyway.

The more I have thought about the issue, the more I'm thinking a Turn-Out Tune-Up will be the answer. I'll have to do some more investigation, though, before diving in. While you two are right in that a different turn out would certainly be better, the amount of construction that would be needed in this section of my layout to swap it out would be immense. And if the end goal of all of that would be swapping out the turnout, why not try tuning first, right?
 
Well, I'm not sure how you can tune it much..Perhaps the plastic flangeway in the frog right where rear wheel is is too tight. Or as you say the check or guardrail on the other side may be the cause. You can widen them with a small file. Other than that I don't know. I must say, the aerial shot of the switch doesn't look like the diverging track is 18"r to me, but more like 16"r and either a #6 or #4 switch..
 
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I'd try a different switch.

Either a #4 (not a snap switch), or perhaps a #6. You'll have to relocate the entire switch a little "to the left" to mate up with the curve on the right for the latter.

(Don't know if anyone markets a #5, but that might be a workable compromise).
 
As I posted previously, the problem appears to be the flanged center driver set. If you aren't up to turning the flanges off, I'd go to a swap meet or ebay and buy a Mantua/Tyco Pacific (4-6-2) or Hudson (4-6-4), both the same except for the trailing truck. The center drivers are blind-flanged on both, and you won't have any trouble handling the Atlas #4 turnouts.
 
After doing some more investigating, slow speed runs, watching, videoing, and meditating on the problem, it looks like the chassis of the loco itself is just not turning as it hits this turnout and rather just tries to stay perpendicular to the main line while the leading pair of drivers heads off on the diverging route. This pulls the middle and rear drivers up onto the closure and then wing rails.

J.Albert said:
I'd try a different switch.
Either a #4 (not a snap switch), or perhaps a #6. You'll have to relocate the entire switch a little "to the left" to mate up with the curve on the right for the latter.
(Don't know if anyone markets a #5, but that might be a workable compromise).
Click to expand...

Of the options you list, a 4 would be only one that could possibly work without major redesign of that section. If I were to go the replacement route, though, I'll just custom build one instead.

OR... Since the diverging route off of this particular turnout is seldom used, maybe I just won't send the Hudson up that track. :rolleyes:;)

Although. the more I think about it, the more I wonder if a complete teardown and build of a new layout may be in my future. We'll see.
 
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"OR... Since the diverging route off of this particular turnout is seldom used, maybe I just won't send the Hudson up that track. :rolleyes:;)"
I have some branch line places that are just too sharply curved for some of my larger locomotives to handle without derailing. I simply avoid running those locos onto that area. But this is completely prototypical! Some engines and some track just don't work together. Pennsylvania T-1's, which had a non-articulated wheelbase, could not be run a number of places and were restricted (IIRC) to main lines between New York and Chicago. In other instances, the weight of the locomotives was just too heavy for the light rails or bridges to stand. So the railroads restricted some engines and rolling stock from running there.
 
OR... Since the diverging route off of this particular turnout is seldom used, maybe I just won't send the Hudson up that track. :rolleyes:
Click to expand...

Most wise of all the choices.

(I once took an older loco with big flanges and ground the flanges down by a combination of running the loco wheels (off the track of course) while using a dremel tool grinding wheel).
 
Need a #6 switch or larger. As others said too tight of a curve.
A friend once told me build your curves and switches for the longest car (autorack for example) and the longest engine (big steamer or 6 axle diesel) then anything you have will go through.
 
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