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Hello, forum denizens!

Our club, the Mendocino Coast Model Railroad and Historical Society, is getting ready to install a 45mm gauge layout at the Mendocino Coast Botanical Gardens (near Fort Bragg, CA, about 3.5 hrs North of San Francisco). It will have depictions of many local historic sites related to our area's rail-related history (mostly logging).

I and a couple of other members have many years of live steam experience (1:20.3, mostly), and all that experience tells us "make the curves as large diameter as possible." However, modeling is, of necessity, compromise! We want to ensure that we pick curve sizes such that we exclude as few engines from running on the layout as possible, while not taking up all available layout space with huge curves. We're contemplating minimum diameters of somewhere in the 10' to 16' range, with 12.5' being one of the current favorites.

From extensive googling (gotta love that verb!), we see that the cab forward and Big Boys need 20' diameters (as I recall---don't have the list or that web site open as I type this). We find a *few* larger engines spec'ed to require 12-13' (min diameters). However, the vast majority seem to have min specs of 8'.

I'd like to request the following feedback from this oh-so-well-informed-and-experienced bunch of folks:
1. Recommendations for min diameters (any specific experiences, positive or negative, would be appreciated).
2. Any issues anyone's had with engines/published min diameter specs.

By the way, the layout will have facilities for electric engines as well, so any experience related to specific engine/curve issues would be good to know, too (I know, I know --- I *try* not to wear my live steam 'blinkers', but it's just so *hard* ).

Many thanks, and Cheerio!
Deb Smith
SA #116
 

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Deb

Long experience has shown that although some of the smaller Aster locos can operate on 2 meter radius (13 foot diameter), the larger engines require about 3 meters (20 foot diameter) as a MINIMUM for safe, consistent operation. My track is an exception in that I have 24 foot radius (48 foot diameter), about twice what most folks try to use as the minimum. Mike Moore's portable track, as well as the Bednarik's (Ryan and Charles) use a 20 foot DIAMETER as the minimum radius, along with seven inch center-to-center on parallel tracks. Even at that, two larger Accucraft K's cannot pass on the curves.

Your comment "However, the vast majority seem to have min specs of 8'." is really about the large number of small narrow gauge engines that have been produced.

Remember, trains look more interesting running on wide curves with short straights than on big chunks of tangent track connected by sharp curves. You are not designing a SCCA sports car race track. If lots of mainline locos will be run (CFs, GS-4s, etc), then they will never be able to "stretch their legs" if you have "restricted speed" curves everywhere. The big 1:20 Ks may operate on shrp curves, but the trains look silly.

Please invest in the space for 10 or 12 foot RADIUS in the beginning design, you will not regret the decision.

Best of luck with your project.

Hopefully your neighbor down the road in Sonoma, Chris Scott will chime in, and maybe travel noerth to give you a hand.

Regards

Dr Rivet
 

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My advice is go as big as you possibly can.

The only engines that have a problem with the smaller curves are the USA BB, and the Accucraft 1:32 engines and such....now trackwork is the essential if you plan on running Accucraft engines the side to side and front to back vasriences are extremely important....other then that most makers of engines are very forgiving!
Accucraft flanges are NOT forgiving and not much fun to run if your trackwork is not perfect!

I would never go less then an 8' curve...that in itself is limiting.


Again my 2 cents

Bubba
 

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Deb,

The track at Adirondack Live Steamers, which I helped design, has 10-foot minimum radius curves, on which a cab-forward has successfully operated. My home track has eleven- and twelve-foot radius curves, with a minimum of eight-inch centers, up to ten inches where possible.

If you are planning to accomodate guest operators and their engines, there is a small but growing group of builders in 7/8ths scale, and such equipment can be six inches wide, but usually short. The eight-inch minimum center distance should be good for them, too.

Good luck on your project.

Larry
 

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and don't buy "all ready curved" track. Buy straight track and bend it to your radius; that way you bend your track to the curve of the table top; not have to adjust your table top to the curve of the track. Also buy a post leveler for about $5.00 to set your posts, way easier than using two clamped on levels.
 

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Jim has given some VERY solid advice I reckon. When laying the track firstly your curves MUST be constant, it's no good having a kink in a 12' radius curve where it suddenly tightens to 8' for several inches. I 've seen it many times including on the big track at DH.
Secondly, I cannot stress the importance of nice long smooth transitions into your curves. These are easily achieved using the bent stick method and a keen eyeball, and will provide for lovely smooth running. If you have nice 12' minimum curves there is no need for any super elevation, and try to make the track to an interesting shape rather than just an oval.........use your imagination.

David M-K
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At our track at the Houston Area Live Steamers, we went with 20' radius on the main lines. Every part of the track was designed to accommodate the largest possible engine we could envision runing on the track, one of our member's Aster Big Boy. But that engine doesn't have the largest rigid wheelbase that has run on the track, I think that would be Steve Speck's Berkshire. In any case, remember that you also need large-radius switches to accommodate the large locos. When we built the track, we used #6's, the largest ones readily available in Code 332 rail at the time. If I were to go back and do it again, I'd use #8's. We also had to go back and regauge the guard rails on the switches (we used Aristo #6's) becasuse they weren't built to the fine-scale gauge standards of the Aster and Accucraft G1 standard-gauge (1:32) engines.

Also, if your track is going to be in a public area, especially if it's going to be on the ground, I'd suggest using Code 332 track. It's much more robust and resistant to inadvertent and deliberate damage than Code 250 or 215. Since our track is in a public park and subject to vandalism, that was the reason that we chose 332. Thankfully, we've only had one instance of it, and it was while the track was under construction -- someone grabbed on of the unfinished ends of the rails and yanked. Luckily, because of the weight of the rail, they only damaged one tie strip and a few feet of rail.

If you have the room, go as wide as you can; it looks much more realistic.
 

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Deb

I see the issue of rail dimension has gotten its nose under the tent flap. My personal bias is to keep live steam off the ground, especially if you cannot control who walks in the area. Code 332 is more robust, but the finer (smaller) dimension of both flange depth and tread width on the wheels for both 1:20.3 and 1:32 models mean that you need to shim the frogs in turnouts and may have to adjust the gaurd rails to insure that wheels do not "pick" the point of the frog on the diverging route of a switch. Cosde 215 looks beautiful (I used to use it), but code 250 from Sunsrt Vally RR or Llagas Creek is a better choice. The switches from either of those two work well. I weould NOT use less than a #8 turnout on the main line with these long wheel base locomotives. The rigid wheelbase of the Aster German BR86 2-8-2 tank engine is longer than the Daylight because there is very little lateral play in the drivers. It will not reliably negotiate #6 switches. One other lesson learned after several years of continuous reconstruction of the IE&W Ry; stagger the track joints, especialy on curvers, by at least 12 inches. It helps keep the kinks out and makes putting transitions in at the end of a tangent section.

All the best
Dr R
 

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Bottom line: Go with as large a radius cuves that you can. When I rebuilt my track I went from 10 foot to 14 foot radius. If I could have I would have went larger. We have two BB's that run on the track and do fine, but wider would even be better. The code 250 rail does look better, but my track gets so much use that I went with the 332 because it is easy to get and IMHO seems to be more robust too.
 

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You don't mention if the track will be at ground level or frames off the ground. If so, use a small hydraulic jack to lift and hold the frame in place while attaching it to the post(s). A lot easier on the back and tempers.
 

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Discussion Starter #11
Hi again, everyone.

Thanks very much for all of the informed responses. I'll be sharing all of them with my fellow MCMR&HS members.

Adding some info that I unthinkingly left out of my original post:
- Our layout will be elevated.
- The area where we'll be does have a grade to it, but we do plan to have *no* track grade. This means for one area to be no more than 4 feet (or so) off the ground, another area will be very close to the ground (we've not done a real survey yet, but by a good estimate-by-educated-eye, will probably be 1.5' - 2' off the ground).
- We were planning on code 332 track, since one member (Tony P.) generously is donating some that he has already available. Since one area will be so close to the ground, the odds of it being stepped on at some point are rather high, too!

Thanks especially for the info on switch sizes. We had spoken some about them, but your inputs have given us lots of data that we didn't have previously.

The construction advice is appreciated, too. Some of the larger, already-constructed "scenic" modules have existing support systems already in place.

FYI: For the new ones we need to build, we're planning on using a product called Redi-Footing (http://www.redi-footing.com/). These consist of a footing and a separate top bracket that holds a 4" x 4" (or two 2" x 4"s, natch), and uses heavy walled 4" PVC pipe in between. Without concrete, or anything else required, they'll each hold more than 10,000 lbs (they're designed to be piers holding up decks/buildings/etc.). Their ease of installation makes them ideal for us in any areas where we cannot get enough free materials for the supports.

Thanks again for everyones' inputs so far! I'll keep checking back to this thread, in case anyone wishes to add more/different "food for thought".

Cheerio, and Happy Steaming!
 
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