Just looking for some input on a design I drew up for a compound yard ladder. I am working on designing a double deck layout, with one level dedicated completely to a staging yard. My original plan used a standard ladder track arrangement, but after I decided to increase the center to center track distance to 2.5", I thought I’d give the compound ladder a try, to better maximize the length of all the tracks, and keep them more consistant. My concern is the ‘s’ curve that is naturally created where the right hand turnout is joined to the left hand turnout, after a short tangent of track. All turnouts in my plan are #6s. The 3.63" long straight between the right and left hand turnouts should ease the effect of the ‘s’ curve, but will it be enough? I hope to run all the usual modern day equipment, but is that possible? I thought of using #8 turnouts in place of the two #6s, which cause the ‘s’ curve, but when I layed them over the plan, I noticed I did not gain anything. Probably due to me keeping the same center to center track distance, which requires a 3.63" long straight between the #6 turnouts. With #8s, I need no extra track to maintain the spacing.
I don’t think your ‘S’ curves are anything to worry about. They are no different than what your trains would run through when entering a passing siding or going through a crossover. You aren’t going to be running through the yard turnouts at high speeds (although your kids/grandkids might![swg]). If your equipment is properly tuned you shouldn’t have any problems.
Or a yard related S curve. Standard yard ladders typically have S-curves and they are part of the geometry. Usually it is difficult to avoid S cuvevs in yard ladders so don’t fret about it. Naturally it is good to avoid them as much a you can, but I don’t see any particular problems with the ladder you depicted.
You show a 16 inch straight section before the curve which is good. IIRC, John Armstrong recommended a straight section where possible of the distance of you longest car. As a rule of thumb, I try to put in at least 12 inches where possible.
Thank you for the replies, guys! I appreciate them. I didn’t stop to think about the obvious - that any turnout creates a natural ‘s’ curve. I guess I was just thinking too deeply at the moment I began to nit-pick my track plan. After reading your comments, I agree that this compound ladder should be fine. Worst case scenario, I can simply avoid running the trains that have extra long rolling stock or motive power into that track in question. Personally, I think it will be fine. Once I get to building my turnouts (Fast Tracks), I can try some mock up testing.
Speed is a factor in how far you push things with S-curves, which is one reason you can get away things in yards that would be an issue on the main. Still, do your best to maximize the spacing between turnouts and you’ll minimize the chances for problems.
Another trick is to use more commodious trackage to serve tracks, like at the pig ramp, where long cars will be the norm and tighten up for other tracks, which are likely to see no more than an occassional long car mixed in with other shorter ones. It’s the two or more long cars in a row that really get you, so where there’s mixed freight and thus mostly shorter cars, tighter turnout spacing and the potential for S-curves turns out to be less of an issue that sometimes thought.
Geometry question
If you angled that horizontal feed line down at something like 20 degrees would it affect your track spacing running down the side?
(sorry I used to be great at geometry, but the old mind is not quite working as good as it use to).
This is something like what I had been considering,…using all Peco ‘mediums’ …
Would that compound ladder example sited as #2 above still hold up with its track spacing down the side, if the horizontal feed line was slanted down at something like 20 degrees??
Brian
Rotated 25 degrees
(oops, looks like more due to distortion of photo size)
I think this answers that one question I had.
I’m not as enamored with this ‘compound’ arrangement as much as the ‘pinwheel’ one. The switches are not all lined up along the edge, and it takes a little more thought as to what number track you are entering.
There is actually a reason I believe I prefer the pinwheel arrangement. Tell me if my reasoning is incorrect.
If I power all of the turnouts with switch motors they could all be located on the front curving edge of the staging deck plywood,…within relatively easy reach for servicing/replacement. Or they might even be manually controlled from the front edge of that staging deck??
This was my original track plan for the ladder. I was going to have all the switch machines (Peco’s) lined up along the rear edge of that supporting plywood deck (not shown so close to the edge in this dwg), and be able to access them from that ‘hollow triangular space’ between the staging deck and the shed’s corner.
If I now place the ladder turnouts out on the front edge, I will have even easier access.
I’m not a geometry or track planning expert, but I’ll do my best to try and answer your question.
The short answer is I can build a yard ladder at any angle I choose, and I can also control the center to center track spacing by trimming, or lengthening, the rails of my turnout’s diverging route.
The more in depth explaination goes something like this. All commerically available turnouts have what I would call ‘fixed geometry’ out of the box. The angle of the diverging route is whatever the manufacturer makes it. The rail length of any turnout’s diverging route is also determined by the manufacturer. These two things affect the track center to center spacing. You have the option to trim the diverging route rails shorter, or you can add a piece of track to lengthen them. If you do neither, and you simply go to town laying track, your track center spacing in a yard ladder is going to end up at some fixed dimension. To better illustrate what I mean, I drew up some yard ladders.
Here you can see my original compound ladder at the top. Notice I have some short pieces of track between some of the turnouts to space the diverging routes further away from each other. 2.5" on center to be exact.
In the second ladder design, I simply connected all the turnouts to each other with no care or worries of what my track spacing would become. The result is a 2" center to center spacing.
The third ladder design is my original arrangement, but now letting the yard track simply be a straight tangent. I still have my 2.5" center to center spacing, only because I have some additional (short) pieces of track in between turnouts. They are about 3".
Brian, I guess you were typing two responses, while I was busy drawing and replying to your original question, but no worries!
You are correct. A standard ladder would have all of your turnouts located along the edge of your layout, which could be helpful in certain situations. On the prototype railroad, where safety is important, a compound ladder would require the brakeman to cross a lot of tracks to throw some turnouts. I’m sure that is why the compound ladder is not often used.
For modeling purposes, especially for a staging yard (that is probably out of view), the compound ladder has an advantage. More consistant lenths of track. A s
I built a mock-up of my planned compound turnout yard throat on the living room floor and tested all my locomotives/trains through it, and they all worked perfectly. I used Kato #6 turnouts and track pieces, which will be what is used on the actual layout.
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I would suggest you do the same with the track pieces you plan to use.
