Keep in mind this is just my plan for my layout. This is what I want to include on the layout. Nothing is set in stone, except the industires I want to model. I just did a crude drawing on microsoft paint. the track plan is not exact. Basically, it will just be a simple loop, with the industries I want to model. The helix in the top right hand corner will go up to a seperate logging line. After some rethinking, and measuring I find i can fit a 15 inch radius helix in the corner with a 4% grade leading up to it. so the mainline can still travel underneath the helix. The only locos I plan on using on the logging line are shays and possibly a climax. My question is in reguards to the helix. I have never built one, in fact this is my first layout. How do you keep the grade constant while constructing a helix?
here is a basic drawing of the layout as i envision making it. Mostly, I plan on keeping things simple as far as track plan and concentrating on scenery. Basicaly, an oval with some sidings. any suggestions would be welcome. thanks
15" radius… um not alot of stuff will go on curves that small even then there will be a good bit of overhang I recommend atleast a 22" radius curve for a good bit less over hang. Plus you will be able to lower the grade to 3% wichwill thus enable you to run longer trains on the helix.
EDIT; wait is this n scale? if then I think that 15" radius will be ok but I don’t do n scale so I don’t but you definently want to lower the grade percentage for n scale to about 2% less is better if possible.
First we need to know what scale you are using. If this is HO, then that 15" radius helix will be a little greater than 4%(figure 4" rise for each loop of the helix). The real problem is that that sharp curve will also figure as ‘drag’ due to the tight radius. The prototype usually figures about .05% for each civil degree of curvature(this is someplace between a 55-60 degree curve) - That adds another 2.75% to the adjusted grade. You now have almost a 7% grade! Most Shay geared engines will have problems with binding of the outside drive shafts if the drive shaft side is to the inside of the curve. They also may not be able to pull themselves up that grade.
For N scale, you will need at least 2" clearance or each loop of the helix. That gives you about a 2% grade, with the curvature adjustment adding about 1.5% - For a total grade of 3.5% - Manageable.
At the club I belong to(HO) we have a helix from ‘staging’ to the ‘on stage’ part of the layout. This helix has 33" radius curves with a 4" seperation between loops. A pair of Kato or Athearn Genesis SD70MAC’s will just pull a train of 35 cars(with metal wheels) up that hill.
Jim
I built a single track 18" radius HO helix and it works fine. I’ve seen a 15" radius helix in a layout plan or two, but I’ve never known anyone that built a 15" radius one.
It is built into a closet in a corner of the room. You enter the helix in the middle level and either go up 4 turns to the upper level or down two turns to complete a continuous run on the lower level. It was actually fun to build.
You need to understand (maybe you already do) that only the radius of the curve and the thickness of the roadbed determine the grade in the helix. Watch the grade carefully. The worst thing is to run a train in the helix and have it not come out because it is slipping because the grade it too steep.
I sat my 18" radius sectional track on the roadboard material (hardboard sheet) and made 1/2 a loop (180 degrees). I just traced around the track and cut it out with a jigsaw. Then I used that one to trace out a bunch of others. Then glued them together with a bunch of clamps, overlapping the joints so there is always two layers of hardboard. I used cut up 1x4’s (actually 3/4 x 3 1/2) as vertical spacers and supports. Get the grade very even and constant on the 1st level and build up. Make sure to use a “standards gage” to check clearance everywhere. and test as you go …
Best of luck …
Marty
When I worked at http://www.dunhamstudios.com/rrcontents.htm , on several display layouts we incorporated 14" double helixes, (one up, one down), for continuous running of Riv. Heislers. I don’t think you’ll get away with that with the Shay’s, the universals will come apart. You might be able to do it with 16" or 17" radius, but you’ll probably be limited to 4% grades and about 4 log cars or equivalent.
What year are you modeling? I’m not really sure that a logging line with a shay and a Intermodal yard really go together.
as for the 15" helix (if this HO) I would not advise it esp. at a 4% grade at the very least try to sqeeze in an 18"
bill
A true logging railroad would probably use series of switchbacks to gain elevation. It would add operating constraints and keep the train visible prototypically.
Not knowing the scale is a bit hard regarding a response, but I felt I had to jump in anyway.
Over all your plan looks pretty good. One thing to keep in mind if you anticipate multiple operators is to keep “busy” sections separated. In other words, as an example, a real busy junction directly above, or directly across from a real busy industry can create a space problem in the isle…Unless it’s real wide, and even then one busy scene atop the other is still hard to operate.
As for a helix: Keep in mind that the larger the radius and the less the grade, the more trouble free it will be. Regarding keeping your grade constant: Once you have a grade set (each riser around the first turn cut longer for the desired % in grade) on your first turn, the remaining risers for the remaining turns are all the same length. Get the first down right and you’re good to go.
Even if your helix will only see short logging trains…I would still recommend a min. of an 18" radius. And if space permits, “ndbprr” suggestion of the switch backs is a great thing to do, adding great operational and prototypical fun.
As a foot note: I run HO with a logging operation on my upper level and would have done the switch backs, if that were all the equipment that would be rolling there. But my logging road gets incorporated into the mainline at a junction, and other, larger equipment services an upper level point to point. With that scenario I wanted as reliable operation in my helix as possible. So my helix is a 38" radius, 2% grade. Yes, it took up some space, but in the long run I only lost two 3.5’ dioramas on my lower level and I have a VERY reliable helix that will handle any of my rolling stock and locos. A good trade off in my case.
All I can add is go as big as you can! I am in HO and had built a 24"r. helix between two levels. It was just OK for freight my 4 unit diesel would do it as my cars are all 36-40 foot, So then I tried running my streamliner…Bad Idea! Not only did it look like a toy, those 85 foot cars hung up in every place imaginable, and then some. Long story short I tore it out in a lot less time than it took to build it, salvaging the cork and track. I have run on a a friend’s 30 inch radius helix which is not too bad, but I would go even bigger if I built another! Joe Fugate ended up with a 40 inch radius and it’s cool! Never a worry about steepness or stringlining cars. It just takes time and that does take a bit of getting used to, while resisting the desire to keep inching up the throttle, so that you come out the top screaming like a banshee! Enjoy the process. jc5729 John Colley, Port Townsend, WA