As the title says, I may need to add a turnout that won’t be readily accessible after completion.
Here’s the lowdown: current plan calls for my double track mainline to loop around to the back of the layout and run along the wall. On paper it looks like I should have enough room to run both tracks into staging.
BUT, we all know that things don’t always translate from paper to roadbed so as a contingency plan I may need to add a turnout to bring the double track down to single which will then proceed into staging. To maintain the double track illusion, this turnout would need to be located out of sight. I’m planning on hiding it behind some building flats near the back of th layout.
On the plus side this can be a fully automatic turnout as the traffic pattern through it will be unchanging. Westbound trains travel into staging from the westbound main, eastbound trains come from staging and follow the eastbound main. Therefore a spring switch would be perfectly acceptable.
Except I’m using DCC I can just imagine having all sorts of problems with shorts as trains run through the turnout. I believe unpowered frogs will help. Yes I could install a Tortise or some such but, for me simple=reliable=better
One of the “things I wish I hadn’t done” on my previous HO DC operated 11x15 two level layout was to have a handful of turnouts in inaccessable places (i.e. in tunnels, or on an incline under the main level with no room to get to it from above). My problems were that I often had a couple of them lined up incorrectly and caused a derailment. This was especially likely if I hadn’t run the RR for awhile and I forgot the proper settings. Obviously with DCC and control panel signals this could be eliminated.
I have to say that the Atlas code 100 turnouts, and the Atlas switch machines (some were under table) worked flawlessly for the life of the layout - 11 years. Of course I was pretty lucky in that regard.
My advice to you is not to have inaccessable turnouts if possible. If not, make sure you have them perfectly aligned with joining track (both vertically & horizontally), use an under the table machine if it provides better access, and test, test, test.
I’ve been through this with my new layout (under construction) and the testing is critical - using your smallest and largest locos and those most picky (mine are 2-10 - 2s). AND, make sure your level of “good enough” is significantly up there!
Well, that equation may not totally work all the time, particularly when applied to the Tortoise. It may not be the simplest system out there, but I think you’ll find a lot of votes for the most reliable. (I’ve only had my Tortoises on the layout for a couple of months, but so far, so good.) While they are a bit more effort to install, they’re not rocket science.
The Tortoise comes with built-in electrical contacts that reflect the position of the turnout. These are often used for signals or panel indicators, but they can also be used to control power to the incoming tracks. So, you could isolate the two frog-end tracks several feet from the turnout and then feed them through the Tortoise. (To me, this is more reliable than using point-rail contact and feeding them from the frog end of the turnout tracks themselves.) If the turnout is thrown the wrong way, the incoming trains will stop before getting to it.
I would add signals to the whole thing, visible from the outside. This will remind you of how the turnout is set, and besides, signals add a lot to your layout’s realism.
You could also totally automate the operation with some sort of detection circuit to throw the turnout based on which track a train was arriving on. That’s adding significant complexity, though.
I have one spring switch currently in use (in a reasonably accessible location) and am looking forward to putting three more into a truly inaccessible area. The design is similar to a single-point street railway turnout, with the single point spring-loaded (by its own tension) against the stock rail.
While the turnouts themselves may be all but impossible to access, there is no reason why the electricals have to be. I use all live frogs, and the connections are all brought out to the fascia lines before being routed to the appropriate polarity controllers (relays operated by panel switches.) If the frogs don’t have to be powered, the electrical complications go away.
As for the turnouts themselves, I hand-lay all of my specialwork - and insist on near-perfection in gauge and flangeway clearances. As a result, derailments of properly weighted, properly wheel-gauged rolling stock simply never happen. (The only problem I ever had was with some light-weight, out of gauge kitbash fodder that I test-ran without a pre-op inspection. Never again!)
Which leaves one, final, issue. Never, ever, reverse a train that hasn’t fully cleared a spring switch from the less-preferred route!
Chuck (Modeling Central Japan in September, 1964 - with spring switches)
If an inaccessable switch must be used, I recommend a Tortoise or other switch method that you can get feedback for position. The torti has switch contacts that your can wire to an led to verify position. This might help with derailments.
Well one of my goals is to have this turnout be invisible to the operators. Meaning not only out of sight but out of mind so they don’t have to worry about throwing it. Hence a spring loaded turnout which requires no operator interaction. The points can be spring loaded to send trains from staging onto the eastbound main since that’s the only place that trains from staging should go. Trains traveling into staging will always be on the westbound main. These are the ones that would run through the switch possibly causing shorts.
Adding any kind of turnout motor would then require someone to operate it and remember to operate it. Adding humans to the equation upps the potential for accidents.
I’m ok with unpowered frogs if they alleviate the potential for shorts. My locos have enough power pickup that they don’t notice unpowered frogs.
I have an idea for a simple siginaling setup to prevent collisions on the unseen track. A simple form of block detection but I need to have an electronics buddy do some calculations to see if will work.
Consider why spring switches are not commonly used in similar situations - both accessible and non-accessible.
Are your wheel sets consistently weighted and gauged? Is the weight per wheel consistent from one car or locomotive to the next? In other words, can you safely assume a reasonably uniform pushing force on the points from wheels entering from the frog end?
Can you assure that the points slide freely enough so that a rather small spring force will hold the point tight against the stock rail for the favored route?
Basically, you have to assure that the wheels won’t split the sprung point entering from the point end. And you have to assure that the wheels can generate enough force to overcome the sping and push the points to the other side when entering from the frog end. Not too difficult in the larger scales, but friction forces don’t scale reliably down to HO and N. All it takes is for a little something to prevent the spring from pulling the rail tight, or a wheel from pushing the point over, and you have derailment city.
I’m not sure a mechanical spring switch would have the same reliability as a switch machine hooked up to some sor
I have to add my two cents worth here. I live in a mobile home and have a shelf layout along one wall of a carport. Back and forth switching altho fun can get old after a while. My solution was to run tracks out to a storage shed and there have a twin loop with a spring switch on each loop. This worked quit well but the spring switchs required some attention as to smooth easy throw. A shot of graphite once in a while helped. The other issue was that the weight of all rolling stock had to be great enough to force the turnout toward the spring side. The spring had to be just strong enough to force the point into the normal position. The ability to have a switching operation and send a train into the hidden shed loop and bringing another train back in really enhanced the operation. Having the switch in a position that could not be maintained is sure to cause some frustation.
Spring switches in smaller scales equals bad idea for reasons Fred already stated as well as having a long section of electrically-dead track to avoid shorts. Don’t do it. If you must “set it and forget it” I suggest using sensors controlling a switch machine to automatically align the route.
The best solution is to have two switches for a crossover (only the one has to work and the other can be permanently spiked) and have the dead track end as soon as it is out of sight. This will give the illusion of double track into the yard but be single in reality!
My only venture with spring switches was decades ago when I modified a Tru-scale kit turnout to simplify a reverse loop located 10 feet above the floor! My most inspiring benchwork design to date and a masterfull use of angle iron supports attached to the ceiling beams. To keep track of traffic flow, colored lights courtesy of Radio Shack were mounted in a panel suspended below the benchwork. I would not hesitate to use them again if so required.
There are a couple of simple reasons why I prefer spring switches over any kind of mechanical (or electromechanical) point mover for use in inaccessible places:
Any mechanism with moving parts will eventually require maintenance. The greater the number of moving parts, the more frequently maintenance will be required.
My ‘street railway single point’ spring switch design has ONE moving part - and it doesn’t move much. (I don’t count the relay or the current controllers that actuate it - they aren’t buried under a mountain and a deck of upper-level tracks.) It isn’t a standard turnout (2 points, throwbar, one to four pivots, plus tensioning mechanism or throw linkage.) Even after l’affaire RTR fiasco the only attention it got was a short visit from an NMRA track gauge - which simply verified that it had not somehow gotten out of alignment.
I will not hesitate to put a similar spring switch where the sun ain’t never gonna shine. I am not anywhere near as confident about a Tortoise, Rix or KTM twin-coil, RC servo… Even the fishing leader I use in my remote point linkages will eventually wear out. About the only thing that will render a spring switch of my design unserviceable is a fire.
I think Chuck is catching on to what I want to do.
My idea of inaccessable seems to be different from the typical modelers idea. I will be able to access this turnout but it will require a ladder (upper level of layout) and a reach of abour 3 feet. It will be hidden from view by some building flats which can be removed easily. It will not be buried under a tunnel or another deck or anything that can’t be simply lifted and moved out of the way. Worst case is this section of the layout can be pulled from the wall and taken to the workbench but that’s a hassle.
I’m a mechanic by trade, so I’m pretty familiar with inaccessable components and faulty electronics, both of which I would preferr not to deal with in my hobbies. Rube Goldberg works at many auto manufacturers.
Minimal number of moving parts and electronic doo-dads works better for me, K.I.S.S.
OK so now we get to the discussion of why a spring switch may not be the way to go however, I still havent heard any convincing argument as to why. So the turnout needs to be installed and checked thoroughly before installing, doesn’t every turnout? Cars need to be properly weighted and guaged, shouldn’t they be for any layout? Electronic controls can be added but there’s added comlpexity and expense, does it work better enough to justify its use?
Hmm, the crossover idea may have some merit but still would require attention from someone and would likely have to be on a curve so operators can see it. I’ll have to check the track plan to see if/where this may fit.
If a train stops or derails while part of it is on the spring switch, you can’t back it out. While backing out is probably not in your operational plan, it’s something that may happen at some point.
I haven’t done any “train detection” circuits myself, but in this situation, I would use this as an opportunity to install infrared detectors on both the incoming tracks, and use that to throw a turnout. I’d route power to the tracks based on the position of the turnout, so the trains would stop if if the detector didn’t do its job, and add signals so the operators could see what was going on, too. Yeah, it’s the opposite of KISS, but one thing I like about this hobby is that I get to do stuff like that, just for fun.
You favor the spring switch arrangement. I have no problems with that - it’s your choice. To get it to work reliably, you are going to have to set the spring tension at significantly less than the force required for your lightest car to push the point rather than climb over it. And that spring tension - whatever value it is - has to be sufficient to hold the point securely enough to prevent picking the points. The tolerances for success are simply much tighter for the spring solution than for the switch machine and detection solution. And the
If I understand your situation correctly, I believe “Gantlet Trackage” may be just the ticket for you. For those of you unfamiliar to the term, you can see a diagram in Fig 3-9, Track Planning for Realistic Operation (3rd Edition) John Armstrong. For those of you who do not have that reference, imagine a cross over that only goes half way across the other track before turning to parallel the other track and then crossing back out. There are no moving parts to maintain, though wiring may require the sections of the rail that actually cross to be electrically isolated and probably unpowered. Just my thoughts - Hope this helps more than it hurts
There is another type of trackage that exists (don’t know the name) where one track goes and almost touches the other but dose not cross it, again mostly found at bridges.
Yes, rrebell, that is what I am talking about. It is called gantlet track. Sorry that my descriptive powers and computer skills are inadequate to either describe or illustrate but you understand what I am attempting to describe
No, at least i believe they have another name for this, a gantlet track has a cross over as I understand it, but this is where one rail never crosses another but the two sets of track almost touch, no clearance for two trains.