Short Radius 'Y' Turnouts

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beiland

Well-Known Member
I have been carrying out some experiments on shimming the guard rail slots on Peco turnouts to improve their performance (on another subject thread). I have not yet posted many of my findings yet, but I did start out experimenting with these little compact curved Y turnouts. I was quite surprised to find that a number of my 8 main driver steam engines actually made it thru these turnouts okay,...at least in the forward direction. I have NOT yet shimmed some of their guard rails to see if I can improve upon their performance, but I am rather confident I can,...at least in the forward driving direction.

What concerns me the most would be an analogy with the much larger radius dbl-curved Pecos that had problems with rail cars BACKING thru them. Since the radius of these small Y's is effectively 24” compared with the inner radius of those dbl-curves at 30” , one would well image these short Y's will be very susceptible to derails when cars or engines are backing thru them. Will the shimming of the guard rails solve the problem??
https://youtu.be/tNQSIiZ5ob4




If things work out with the shims, I'm going to need 6 more of these 'little monsters',...as I now refer to them,.....ha..ha
 

beiland

Well-Known Member
Backing thru the Y's

I did some more testing,...backing some of my locos thru these short Y's in addition to those forward test I ran.
I ended up trying to run all of my steam engines (those I had chosen to use on my Shim test) backwards thru these small wye's. None of them had a problem.


I subsequently got out 3 older freight cars I had setting around. They all have relatively small (shallow) flanged wheels. One of them had those older style sprung trucks.

Individually they all went backwards thru the wye with no problems. I coupled them up into a group of 3, still no problem.


I then experimented with providing some resistance to the 3 car group by pressing against the lead car. This DID produce derails,... and often. It was particularly noticeable on that older car with sprung trucks. I imagine this would simulate trying to push a long string of cars thru,..more resistance,...more derailments.


I'll next try shimming a few of these wye's and see how that turns out. BTW, I think only the inner, tighter radius turn needs shimming.
 

Selector

Well-Known Member
I believe the 'difference', if there will be proven to be a difference backing longer and diaphragm-equipped passenger cars through tight radii and sharply curved turnouts, will come from the minor compression of the couplers, which in turn will cause strong and disruptive contact with the inner faces of the diaphragms toward the centre of the curve. I don't see shimming to take care of a problem above the frame, but it should help to guide wheels with a bit more lateral motion to be squeezed out of the design. So, slack action at the couplers is likely to be what may trip you up...in my estimation.
 

beiland

Well-Known Member
Did you watch that video I posted above? ...no long cars, and pushing then thru the 30" inside radius of the dbl-curved Peco,...derailments due to wheels being forced out against the outer rails of the curve.

Of course there are other instances with longer cars, etc, but I was trying to get out the more common problem with just 'ordinary'freight cars. And if there are problems with 30" radi, then certainly there will be problems with 24" radius of the short Y's.

This fellow says he has solved his,..
Purchase some .010 styrene strips and glue them to the inside of the guide rails
1596198933731.png
 

Selector

Well-Known Member
I use hand laid Fast Tracks type turnouts and several new and older Peco Steamline Code 83 #6 turnouts exclusively. I don't get derailments. At all, in any direction of travel. Maybe my wheelsets are gauged differently.
 

beiland

Well-Known Member
The Peco turnouts are famous for their slightly oversize guard rail slot on the outer rail across from the frog,...it was designed like this for Euro trains that often have those 'cookie cutter flanges'. So shimming them like shown in the photo, and on that video, usually takes care of the problems.
 




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