Ok, that's because I was too lazy to check the dictionary for the correct plural of helix, which is as follows, HELICES.
Ken, very impressive! I have build 3 Helices (thanks for looking up the plural; I never would have known....) for my current layout using the traditional "straight stack" method. The "staggered" approach seems to be much easier and faster to do than doing cookie-cutter roadbed. Also it is using less wood, as you can cut all the roadbed from one sheet without any waste. As the radius increase as the trains move up: Do you observe an increase in pulling power as the trains get higher? I know that mathematically the grade will decrease, but des it impact loco performance? I have one more helix to go (if I ever receive a land grant to the next basement room from my wife...), and your photos makes me consider following the construction method. I like it!! Cheers Dirk
Dirk: I am wrapt with the way the helix project has turned out, and was a lot easier than I thought it would be. In the limited amount of time that I have had running trains up and down the helix I can say Hmmm... maybe some increase in pulling power as the locos near the top. It's something I hadn't really thought about. I did notice that there was less wheel spin (on a pair of locos that I really loaded up with a long string of cars) as they got near the top. Still, I haven't done enough testing to be sure. Tbone: My plans? You should check out the "sticky" at the top of this forum. I have Dave H. to thank for the doing all the planning and working out the maths for the spiral helix. He has given me a lot of support and guidance during this project. Anyway, feel free to use any of the information, plans and methods presented here. Just be sure to post pics and add you own personal spin on building a helix, enjoy!
Dirk: I think Ken used the Spiral Helix Dimensions Calculator stickied at the top of the Layout Design forum. If he used the numbers provided, then the grade through the entire spiral helix would remain the same and each loop would rise a little more than the loop below it. Take a close look at this support for one of the helixes on my layout. Since each loop is a little longer than the one below it, and since the grade is the same throughout the helix, each step up rises a little bit (just barely visible) more than the step below it. Because the grade remains the same, the loco performance doesn't change as it rises through the helix. This is a pic of the supports Ken used. Notice how the steps in his helix also increase in size with each loop. Loco performance wouldn't change. On the other hand...If a modeler chose to keep the same height for every step up, then the grade would reduce as you described...but then you would need to add another loop or two to make up for the height you would have gained if you had maintained the same grade throughout the helix. There is another negative side effect of reducing the grade through the helix by limiting yourself to a fixed climb per loop despite a longer circumference: you increase the outside diameter of the helix by twice the width of the ramp/loop for every loop you add...so adding another loop with a 1.5 inch wide ramp means your bowl-shaped helix will have a 3 inch larger diameter for each additional loop. I suppose there is a way loco performance might be affected...In a bowl-shaped helix, the radius of the helix constantly increases from the tightest at the bottom to the largest at the top. As the radius increases and the curve of the helix gets less, there will be a VERY slight and VERY gradual reduction of the total amount of friction caused by pulling cars around the curve of the helix. My guess is that most modelers wouldn't even notice it unless they deliberately focused on trying to perceive it. Check out my blog and albums linked below for more helix info.
Hey Cleggie, what is the size of your helix as far as one side to the other.I want to make sure I have room.Thanks
Dirk: When I composed my reply above, I hadn't paid attention to Ken's observation about less wheel slip at the top of the helix...but, in retrospect, I'd guess the reduced slippage he reports is directly related to the reduced friction as the curves open out in the upper loops of the helix. There is another possibility: If a 1/8 inch wide saw blade cuts on the upper side of the pencil mark for a step in one support, and cuts on the under side of the pencil mark for the next support, and the two pencil marks are each "off" by 1/16th of an inch in opposite directions from where they should be, then (hypothetically) it would be possible for the higher step to be 3/8ths of an inch below where it should be. In the distance between two supports (perhaps a little over a foot), a 2% grade should rise about 1/4 to 3/8ths of an inch from the 1st to the 2nd support. If the second support is 3/8ths of an inch below where it should be after the track has traveled over a foot, then the grade of that portion of the helix may be 0% instead of 2% (and it may jump up to almost 4% to compensate enough to reach the 3rd support!). Tbone: You are certainly welcome to any of the helix information posted in my blog, too; and one of the admins stickied the Spiral Helix Dimensions Calculator so folks would have easier access to it.
Hi Tbone, Just a brief outline of the overall dimensions: The base board is 47" x 47" (1200mm x 1200mm) the MDF I used comes in 1200mm x 2400mm lengths and the helix managed to fit snug within those dimensions. The top spiral is 46" in diameter (measured from outside to outside of the roadbed) The roadbed is 1.25" wide and there are six loops giving a total rise of 16" The minimum radius is 16" (centerline of the track) The hole in the center is 30" diameter, plenty of room to stand up in. You should download ppuinn's (Dave H.) Excel spreadsheet from the "sticky" and have a play around with the numbers. You can tweek the numbers to your own situation. By reducing the minimum radius to 12" for example you will end up with an overall foot print for the helix of something a little less than 40" x 40". Anything less than that will start to put the squeeze on access in the middle for you to stand up in. The helix does take up a fair bit of room and trains will dissapear from view for quite a while but I like the extra level it has allowed me to create. It is an interesting build and I am having a lot of fun with it. Even Tina Marie likes it and can't wait to see me run trains. So that's gotta be good:tb-biggrin:
I have made some changes to my basic plan, the upper level is now the "scenic" level and the lower for opperations. I have made a rough scetch to give a feel for how things will look. The red lines are track and the blue lines benchwork. The dotted red line indicate the helix track and the arrow points downhill in both cases. I intend to run trains up and down on both helii. The back track will be at a higher level than front track to add extra interest. The center track has a long passing siding for layovers, crew changes and to allow for more than one train to opperate on the upper level There are two reversing loops in this plan, so a train can travel from the lower level up helix I, around the upper level and return back the way it came. It all gives the impression of trains having some where to go. The lower level track plan will be changed from the plan I had. No details at this point but there will be a big yard for arrival and departures and some local industies to serve.
Here is a track plan for the lower level. The red arrows indicate travel up the helix to the upper level (red dotted line) I also realised that I was not going to reach track work at the back of helix II so I cut the benchwork short and allowed a "pop up" area. Wiring should be easier than the upper level as there are no reversing loops. This is only a general idea of what the layout could look like and I am open to suggestions. I would like to have a flour mill and grain silos also an engine service facillity somewhere.
Made some more progress, built the sub-roadbed for the return loop on helix1. It is also the exit from the helix to the upper level. All of the main line turnouts will be motorised. Getting ready to transform the blue foam prairie. Atlas MP15DC doing the track testing duties.
Man, Ken. That's even more impressive with the track mounted to it. Keep those pictures coming. I'd never be able to make something like that and it turn out half as nice as yours. Did you ever figure out how many cars you can pull up the helix without having any problems?
txronharris: I have a pair of Atlas SD60M's that can pull about 24-26 cars without any problems. One loco on it's own about 15 cars. What worries me is coupler failure half way up and having a cut of cars rocketing back down the helix at speed and a massive derailment. I am not running trains at the momment untill I have the main line complete, but I will experiment with which car run the best together then.
That is one thing you really need to worry about so you need to make sure you have reliable couplers. During a tour at the layout I was helping operate for the day my one friend was running a full Kato Santa Fe passenger car set(13 or 14 cars). Now these all had the older Kato couplers that weren't always reliable. Well he got about 75% of the way up the helix and all of sudden all you could hear were all the passenger cars whirring back down the helix going faster and faster with each loop. They actually made it all the way down to the bottom, even making it in and out of the helix at the hernia thankfully. However because at the exit the curve changed from a left to a right that's when the bang came. One car got fired out the portal but every other one piled up in the helix. Thankfully nothing broke or hit the floor but it was probably the scariest noise and what seemed like an eternity for it to end. But the MOW had a heck of a clean up in the helix. Needless to say any of the older Kato passenger cars have been updated to the new design so the only one's we worry about now are the accumates.
I can't wait to follow the progress of this layout (much like OC's ATSF). If your scenery skills are half as good as your woodworking skills this layout will be killer! Seriously your benchwork is beautiful. Another thing I like about this layout is that it's not a basement empire...it's just a nice-sized bedroom layout. There's something about that fact that makes it more inspiring for me, someone who is working on a door sized layout. I know in my lifetime I'll never have a 50'x50' basement triple decker 100 scale mile layout. But maybe, just maybe I'll have a bedroom with 2 or so free walls Please keep us up to date on this thread and your blog with tons of pics!
Never say never. Until recently, I thought that I would be limited to an 8'x2.5' (only 2.5' due to arm reach) switching layout in my basement. Then I figured I had a storage room that measured 6'x13' which wasn't being utilized to its full potential. So I am going to store everything in that room in that 8'x2.5' (now 8'x4') area, utilizing upspace as well (very important in being a homeowner - utilizing every square inch you own!). Now that 6'x13' room will be studded out, insulated and drywalled and then my shortline empire will arise. I am sure there are other people here who have had similar experiences, thinking one thing and discovering another.
Mavrick: I hear you dude, scary stuff. I had a cut of cars break loose while I was standing in the helix and man they pick up speed real quick. I was there to to stop any damage being done but... oh yeah accumate couplers on a Atlas Trainman covered hopper appear to be the problem! Dave: Thanks for the kind words, high praise indeed. Scenery is the name of the game on the upper level. I will keep posting pics as I progress. The next areas I will work on are the dogleg to helix 2 and the return loop around helix 2, some pics... Track work leading to helix 1 The view from helix 1 The benchwork at helix 2 waiting for the sub-roadbed for the return loop.
There has been another change of plans. The track plan will stay the same it's the construction method that will change. I've become increasingly unhappy with the use of foam board for the sub-roadbed. It is just too darned noisy! That coupled with the cost, $29.00 NZD per 600mm x 2400mm x 30mm sheet means I will not be buying any more. and will be replacing the present blue foam with cookie cutter MDF sub-roadbed. I will however use the blue foam as risers and as scenery base for mountains etc. I had high hopes for the use of foam on my layout and am hugely disappointed that it has not met my expectations. I guess the leason to be learned here is I should have stuck with methods and materials that I am familiar with.
One step back and two forward. I hate having to rip up work done, but if it's not right or there are issues then it's gotta happen. I would have stuck with the foam sub-roadbed if it wasn't for the noise issue, it seemed to amplify everything fourfold. Anyway it's gone, I tore it out and brought some more MDF sheets at about 1/4 the cost of the foam. There is still a sheet of foam board on the lower level, that will go as well but at the momment serves as a convenent "hold-all" shelf as I work on the upper level I did a track "mock-up" on top of the MDF, plotted the cut lines then ripped into it with my jigsaw. This single piece contruction will be replicated for the transition to helix 2 as well. The track closest to the wall is an incline at about 2% grade. The mid line rises as well but not as high and the front line is at bench height. The MDF bends nicely to accomodate the differences in height. You can see the height differences in this shot. Front track at bench height, the mid track 1/2" higher and the back track 1" higher. Just waiting for the Liquid Nails to harden as I type this before continuing on with the sub-roadbed.
