Freight Yard Ladder Turnouts

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Peco Turnouts in a Yard Ladder

I'm still working on the possibilities with my freight yard ladder configuration. I'm using Code 100 track.

There was a time at the beginning that I was considering whether it might be possible to utilize the Peco 'Set Track' turnouts due to their short length. I have REJECTED that idea as the curved diverging tracks are too sharp of a radius.

Next came the use of the Peco 'streamline' turnouts, .... 'small radius size'. One of the major appealing factors about these turnouts is the 'effective radius' of curved portion of these turnouts,...24" inches. My thoughts were that any of my trains that could negotiate a 24" radius curve track, could negotiate these turnouts.
( and yes I understand there could be some instances where long cars coupled to short ones MIGHT experience some problems here).

My next thought was what if i were to do some trimming of these turnouts so to make them fit even closer together? That experiment was less than satisfying when i laid out a string of 4 trimmed turnouts (templates), and compared them a string of untrimmed turnouts. The total length of the ladder was only approx 1.5" difference,....not worth the effort to do all that cutting/trimming.

Thoughts then turned to whether I could utilize the even broader radius of the 'medium size' Pecos. I laid out a string of these alongside the small radius ones. You can see there is quite a difference, so they were unacceptable to me.


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Further Justification, Peco Sm Radius (24") in Ladder

I was doing some research on utilizing some Peco 'small radius' turnouts in my freight yard ladder design. I found this very interesting conversation, with lots of good and intelligent contributions. I've highlited some of the quotes that caught my eye, and concerned themselves with those Peco turnouts I'm interested in.

This is the question that opened the discussion
What is the difference between a #4 turnout and a #5 turnout?

You can find extensive detail in the NMRA turnout dimensions Recommended Practices area and other related pages:

In practical terms, a #4 is pretty sharp. Some locos and long rolling stock (like 80' cars) may not take it. A #5 is much more forgiving. I used #5s in my yards, #6 for mainline takeoffs and one #8 for a smoother mainline split.

...from a profession layout designer
This is true for PECO N Scale and for PECO HO Code 75 and Code 100, but the newer PECO HO Code 83 is accurately defined by frog number. PECO N scale Code 55 uses a #6 frog for all the turnouts, but the curved diverging leg has different radii for Small Medium, and Large, for example. PECO HO Code 75 and 100 typically have a #4½ frog, again with different diverging radii past the frog. So they are “exact”, but the curved diverging leg is the determining factor.

The second (and more important) is that the lower the frog number, the sharper the effective curve through the turnout. That means that longer cars and engines will be less likely to derail running through a #5 than through a #4.

For this reason, it's a good idea to match the turnout frog to the minimum radius elsewhere on the layout. To take an extreme, there's no point in using #8 turnouts with 18" radius curves in HO -- the curves will restrict the equipment that can be run.

As a general rule of thumb for HO, the tightest point through various frogs is:
"True" #4 is roughly equivalent to 14"-15" radius
Atlas "#4" (actually #4½) roughly equivalent to 18"-19" radius
#5 roughly equivalent to 24"-25" radius

These calculations are from a series of datasheets published by the National Model Railroad Association. An out-of-date link was given above, the newer version of the website is a downloadable zip archive of .pdf files found at this link:

I'm okay with designating their turnouts using the small-, medium-, and large- scheme, but that just doesn't sound very railroady, so I'm calling my medium- and large-radius turnouts #6 and #8 respectively. Mainly because that's what they appear to be as trains pass through them.

I'm nit-picky about a lot of things but the slightly non-prototypical appearance of my PECO trackage and turnouts is not one of them. That stuff is well-made and very reliable

My contention is that Peco uses #6 frogs for all their turnouts. And as cuyama and others have pointed out, what happens downstream on the diverging route varies from manufacturer to manufacturer.

...photographs of N gage code 55 Electrofrog turnouts. I measured the frog sizes:


So then I would call them #6S, #6L, #7

To distill the original question to its essential essence:

I handlay all of my specialwork, so I'm certain that my #4 turnouts (on my end-of-the-coal-hauler module, built in 1980) and my #5 turnouts (in the hidden staging yards at Nonomura, built within the last decade) are built to the proper dimensions.

That said, one of my long-wheelbase 2-Co+Co-2 EF18 or EF58 class juice jacks can slither through a #5. Trying to force it through the curved route of a #4 will put it on the ground, every time.

Why? Those motors require an honest 24 inch (610mm) radius to operate. The closure rail of a #4 turnout has a radius too tight for the long rigid wheelbase. The axle under the center of the carbody gets pinched over the rails on whichever truck hits the tight spot first.

Iron Horseman

Well-Known Member
There is another factor here I didn't see in the discussion above. It was said that all Peco turnouts have a #6 frog, what wasn't said explicitly is that the Peco code 100 track is not a North American style turnout, it is more European. This means that it doesn't "kink" as much at the points as a USA turnout would. This is a good thing when trying to get trains around the tighter corners. I love the Peco code 100 small radius turnouts for this reason. I think they will serve you well in this application.


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My latest experimenting with the ladder and the freight yard,...again laid out on my living room rug.

The left hand edge of the rug would be the wall of the shed. The first track inboard represents that track along that side of the shed that enters the helix structure and goes down to the staging tracks down below.

The next 2 tracks inboard of that are the mainline track and its opposing end that has looped around in a circle inside the helix and reemerged....dbl mainline.

The next 2 tracks inboard are primarily 'diesel engine servicing' tracks. That long white rectangular shape is meant to be a fueling / sanding / lube stop for diesel engines. One of those tracks will bear off and go into a repair shop down the way (not shown). That one service track close to the mainline will rejoin the mainline on its other end.

The next 4 tracks in are mostly freight yard.

The final 2 tracks in are primarily feeding the steel mill complex, but I imagine the dead end portion at the upper end could be a cabeese storage track (and that cross over track shown will be of the opposite variety, and further down the line towards the mill.

Some additional photos I took so that I might dimension them and make some sort of record to help me remember the possibilities when I go to lay them out on the plywood decks. Unless I completely redesign this ladder due to someone else's superior design, my ladder will have 4 Peco smalls and 2 Peco dble-curves at the head as shown. All of those Pecos smalls have 24” diverging tracks. Other crossover tracks in the yard will be either Peco smalls, or could be Peco mediums.

A difference perspective on this complex.

The big white blob there is the Tichy 400T coaling tower. The tracks I have running under it are not exactly scale as I did not have enough sectional track of the correct radius to lay in there. Suffice it to say that the minimum curves for any of the 'big steam' track will be 24”. And that also goes for the large curve going over into the peninsula area.

It happens to turn out that I do NOT need the original 30” deep shelf for this yard. As you can see by the tape measure I could manage with just 29”, or maybe even 28”. That would allow for a bigger aisle.

Turns out that the also be made slightly wider on the other side as well due to the 22” inner circle radius and the track along the edge of the peninsula. I've depicted that here with an increase in the paper aisle width....


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...from another forum...
The simplest solution for the yard ladder would be to change where the feed to the yard is located on the peninsula from the left side to the right side. I don't know how badly that will mess up your plans for the peninsula though. It will require some crossings to get to the left side of the peninsula. I have shown 90 degree crossings here but you might be able to fit in other angles.​
The aisles are 30" and the peninsula is 24" wide:​
Pinwheel Style, David's suggestion.jpg

Basically I had hopes that some of the trains could enter that peninsula area head on, then disconnect the big locos that brought them there, and let smaller swithers handle the spoting and unloading of the individual cars in the peninsula area. Meanwhile the big steam locos would head off to the turntable/roundhouse area. The diesels would go over to their servicing and/or rebuilding area at the far edge of the freight yardI had thought that this relocation of the lead engines might have to occur on track(s) located along the very left side of the peninsula, rather than those engines ending up over to the right hand side of the peninsula then having to cross back over the central track that brought them into the peninsula area.


More Thoughts on Peninsula Trackplan

So here is an image of the original peninsula plan of TL / FJ plan, posted into my present plan,...

and a blowup of that peninsula plan,..

My initial thoughts are 2 tracks to either side of that long building will be container unloading/loading tracks with cars passing down those tracks with an overhead hoisting systems that lift the containers off the cars and transport them to a stacking/storage area (imaginary) in that aisle-way between this peninsula and the freight yard.

The 'big' locomotives that brought the consist into the peninsula area can then escape one or two ways on tracks (22r & 24r) provided for on the very left side/edge of the peninsula, while smaller switchers and trackmobiles handle the individual cars or groups of cars.

I'll have to do a new sketch for that peninsula area. Anyone want to contribute some ideas for the peninsula trackplan?
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Decision Time on Yard Ladder

Yard Ladder Turnouts and Loops from Peninsula

I have been playing around with the design of the trackplan for this area for a few weeks now. And I have had my share of naysayers commenting about my original use of tight radius curved turnouts at the head of the ladder. There have been a few suggesting that I utilize a pinwheel configuration in the ladder, and I have taken time to give this idea serious considerations. I've even mocked up a few of these possibilities.

I have reached the conclusion that these broader radius loops generated by the slightly broader radius 24”+ plus pinwheel arrangements force my loops of track connecting the peninsula to the freight yard and the turntable, to a situation where the one end of that track ends up in the middle, or to the opposite side of the peninsula. I don't find that to be acceptable (if avoidable) in the overall scheme.

So this is the trackplan design I have chosen. There will be 2 'concentric' loops connecting the peninsula to the freight yard. The outer one will be 24” radius minimum for the bigger locos, and the inner one will be basically 22”. but with 2 spurs of 18” plus.

Those two 18”spurs will be inner legs of the 2 curved (I call them dbl-curved) turnouts at the head of the ladder. Those 2 turnouts will be either a pair of Pecos or a pair of Roco turnouts, both of nice quality. There is the further possibility that I could do some slight modifications to either of these curved turnouts to increase their radii slightly. Shown here, the pair of ROCOs

The first Roco encountered has an 18”r diverging leg and one piece of 18”r track into that second track of the yard. The second Roco encountered has an 18”r diverging leg into a 22” curve, and into the third track in the yard.

All of the rest of yard tracks are fed by minimum 24” diverging legs off of Peco 'small' turnouts in the ladder. Crossovers and double slips can be arranged to make the second and third tracks of the yard accessible by 24”r capable equipment. Even the very first yard track could be linked such as to have 24”r capability further down the line, but that likely will not be necessary as it will be involved with short locos and cars of the steel industry.

I have run some pushing/pulling (by hand) test of container well cars over these curves, and experienced no problems even in the 18” curves which are possibly set as 'off-limits' to these longer cars. And I connected two such wellcars together, and to a VERY short tender car. No problems. I'll post some photos a bit later.


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I hooked up 2 of the Peco curved turnouts to sections of 22" and 18" Atlas sectional track, and ran some container 'well cars' over it. I weighted the well cars with a couple of steel bolts, and I finally hooked a very short tender car to those well cars. Everything with 'well'



Active Member
I'm not entirely sure of the utility of putting that double slip switch where it is, beyond making it look "fancy". It doesn't really seem to add much in the way of operational flexibility as all of those tracks can be accessed equally from the ladder.


Well-Known Member
My thought on the double slip there was that the first 3 tracks in from the aisle were all accessed by 18" radius portions of the curved turnouts. If I sought to put some cars/locos on a few of those tracks that didn't like 18" radius, then they might be accessed by entering by way of the 24" Pecos, then proceed thru the double slip.

Does that make sense? is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to