Depending on the manufacturer, an HO #6 switch may have a diverting route radius of 43" and a replacement radius of 69". An HO #8 may have a divering route radius of 67" and a replacement radius of 113". These examples are based on FastTrack turnouts. The table in Armstrong's Track Planning for Realistic Operations shows radii of 43/56 and 67/110. Last year MR had an article providing vital statistics of the various brands of manufactured track showing there are minor differences among brands.
Anyway, my points (no pun intended) are (1) variations exist among makers of turnouts regarding their radii even though they could have the same frog number, and (2) #6s have quite generous radii although one may still need to be concerned with "S" curves for some rolling stock. It is a question of trade-offs between space, reliability, and appearance. The bed-room sized layout plan I'm working on has #6s and #8s most everywhere except for a few #5s on some industrial spurs. My nominal standard is #6 but using #8s (or equivalent #4 wyes) to advantage (mainly cross-overs where space is available), but dropping down to #5s where spacially-advantageous and long rolling stock/locomotives won't tread.
Mark
I would echo what Crandell said earlier, I'd say use no. 6's in the terminal area, and no.8's on the mainline. The prototype used larger turnouts on the mainline than they did in terminals and passenger car yards.
I'm working on a staging yard with the yard ladder using (Kato) no. 6 turnouts, I've tested it with Walthers passenger cars and had no problems anywhere, even where the no. 6's form an s-curve. I don't remember the exact numbers, but I think a no.6 turnout is equivalent in HO to about a 48" radius curve, so any piece of HO equipment should go thru it with no problems.
667CDP wrote: There appears - at first glance - to be a staggering size difference between the Peco 8's and 6's.
There appears - at first glance - to be a staggering size difference between the Peco 8's and 6's.
The number of the turnout indicates how many units in one direction it will take to divert a single unit in the other direction. For example a "#6" turnout will take 6 inches to divert one inch.
Using the typical 2 inch spacing for HO, a # 6 crossover between tracks will require 12 inches (2 x 6). A # 8 crossover will require 16 inches (2 x 8). These are centerline to centerline measurements. Point assemblies will add to the overall measurement of a crossover.
Using Walthers turnouts, the overall length of a # 6 crossover is about 18.75 inches and the overall length of a # 8 crossover is about 25 inches. Both Walthers and Peco C83 are built to NMRA standards so they would be similar.
For passenger operations though, if you have the space, definately go with # 8s.
Good luck,-John
My prime concern was ensuring that I would have the most reliable trackwork and turnouts for running the longer passenger coaches through with relative ease, and I didn't even think of the whole diaphragm concerns when running through smaller turnouts.
The space that I have available to me ensures that I can expand lengthwise, but not width-wise. Because I have my heart set on the Peco line of track and turnouts, and am running with C83, this limits my options as far as what track is available to me (ie: single, and double slips). Nevertheless, I may look at hand laid turnouts in some of the areas to expand my options somewhat. There appears - at first glance - to be a staggering size difference between the Peco 8's and 6's.
Anyways, the advice that you have all provided is fantastic! It gives me a lot of different options to work with and I appreciate all of your feedback! Thanks muchly.
Any place where you find the train snaking through multiple crossovers is a prime candidate for installation of double slip switches, which both shorten the total length of the specialwork and lengthen the tangent between reverse curves for the train using the straight routes through them.
If you are comfortable with hand-laying specialwork, you can bend flex along your projected centerlines, then roll your passenger stock through and check for operation and appearance. Even if you use all commercial products, you can make templates (on a copier) and use the bent flex track technique to establish their locations. In a passenger terminal throat, especially, a centimeter difference in placement can be the difference between, 'pretty, smooth, bulletproof,' and, 'ugly operating problem.'
Chuck (modeling Central Japan in September, 1964 - with LOTS of passenger traffic)
#6s should be fine for low-speed service, but #7s may be useful if you have closely-fitted, full-width diaphrams. Still, youll want to weigh any loss of yard capacity (which you are willing to live with) with the better appearance of 7s and 8s.
http://www.nmra.com/standards/sandrp/rp-11.html
http://www.cvmw.com/cvtswitch/index.htm
Central Valley makes #7 kits that would be a good comprimise if you wanted to try the semi hand laid route. You can download full size templates of all their turnouts from their site and print them out to get an idea of how much room each takes up.
I'll have to disagree with my friends because I feel that #8's will tend to cost you a lot of room. While they are pretty and long, their angle of divergence will mean tight clearances between parallel yard/terminal tracks. It could be that it won't amount to a hill of beans for you if you have lots of room (particularly length), but I feel I should point out that I use Peco Customline Streamline #6 insulfrog Code 83 in my yard and can run anything I own through them with ease. I even have a handlaid #6 double slip turnout that my Walthers heavyweights and 2-10-4 have no trouble negotiating. Plainly, #6 turnouts will work for all but a brass x-8-x and higher numbers of drivers...probably.
To be clear, if I had the room, there'd be no question...I'd gladly have #8's in my yard. You must determine what "having the room" means for the turnouts you eventually make/purchase because it will be a sour experience to find you have made a serious error. Could be expensive to pay shipping and re-stocking fees to exchange them, too.
Just a thought.
-Crandell
Hi 667CDP
I get a bit lost when numbers for points are used to quote size.
But that aside go for the set of points that has the most gentle transition on the curve that will more than likely be the longer of the two.
Always have the curve on the points as gentle as you can get it, you will get better and more trouble FREE operation that way.
Unless you are realy cramped for space or doing industrial street trackage avoid the realy tight curves on points.
regards John Busby
I was thinking that the #8's would probably be the best choice too. I'd rather be safe than sorry, especially when running primarily large passenger trains.
I definately appreciate the feedback and advice. A hearty thanks!
You'll find that "most" HO equipment will "RUN" on #6 switches. I use the two terms in quotations loosely.
Stick with the #8 switches, and you'll see that your equipment runs smoother, more reliably, etc.
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Hello Again Everyone,
I'm wondering if anyone has some advice on the best sized Peco turnout to use on a passenger terminal oriented layout. I'm going to be using predominantly 'Rapido Trains' coaches, and am wondering if #6's or #8's are best to use with these longer HO scale passenger coaches. Size isn't much of a major issue as there will be plenty of space to expand the layout if need be.
Are #6's pushing the limit with these large coaches, or am I best to stick with the #8's if I can?
Thanks