It looks like my Parkdale Railroad is going to be best served with a helix on each end of the layout. I have read a couple of articles on them and looked at EasyHelix web site. I would be very interested to hear your helix horror story or your success as well. Thanks,
Diligentman: I had a horrendous experience with my first helix, an N-scale double-tracked stacked helix 36" in diameter. A stacked helix has a uniform radius throughout all loops and looks like a cylinder because each loop is stacked directly above the one below. My loops rose 4 inches each time around yielding grades between 3.5 and 4% for the outside and inside tracks, and there was less than 4 inches of clearance between the railhead and the underside of the next higher loop. Original construction was a nightmare because you had to have everything done (roadbed, soldered joiners, soldered electrical feeders, cut detection gaps) before you could proceed to constructing the next higher loop. Maintenance was impeded by the supports on the inside of the helix and the back drop/ viewblock on the outside. Repairs were impossible because there was only 3 inches of space to work in and I couldn't look downward to see where the nailholes were in the flex track and couldn't get an angle to see if I had proper alignment when I replaced a back section of damaged track. Operations were severely restricted by the grade. When I moved 3 years ago, I designed a much larger layout and had 4 helixes, but I made them genuine spiral helixes. A spiral helix does not have a fixed radius like a stacked helix--the spiral helix radius continually increases as the track loops upward. For example, if the bottom loop is 16" radius, by the time you complete the first circuit around, the radius has increased to 17.5 inches. Loop 2 starts at 17.5"; loop 3 at 19", loop 4 at 20.5, loop 5 at 22". With a 2% grade you can rise 16" in about 5 loops. The spiral helix looks like a large bowl instead of a cylinder. The footprint is larger but original construction is relatively simple (essentially the spiral is a 67' long circular ramp in cookie-cutter design), ongoing maintenance and repair are as easy as on regular shelving because you have 100%clear access to the track from above, overall operations are vastly improved because you only have to contend with a maximum 2% grade (which could be even less if you are willing to add additional loops to gain your rise to the upper level). This is a pic of my Kellar Branch helix. My other 3 helixes are circular with a footprint between 48 and 56 inches diameter, depending on which one you look at. The Kellar Branch helix is a 4' by 5.5' oval. I have other materials on building spiral helixes in N-Scale. These include: spreadsheets showing the interactive effects of various grades, number and radius of loops, and width of each loop; pics of my helixes; notes from a clinic I presented at an NMRA division meet; and a letter to another modeler talking about lessons learned from my first helix. I'll try to post some of the other pics. The file size of the other materials exceeds the Trainboard uploading parameters, so anyone interested should contact me by private message about emailing them. Although it is possible to apply the spiral helix concept to HO or larger scales, the footprint for multiple loops consumes proportionately more real estate unless the grade is increased over 2% or unless the radius of the lowest loop is reduced (perhaps to as small as 24" radius). Given a 2% grade, minimum radius of 24", 4 complete loops, and a footprint diameter of 6 feet, A spiral helix in HO would be able to rise about 15 inches (4.5 loops would give about 16 inches of rise. If some of the rise is accomplished before entering or after leaving the helix, then the helix wouldn't need as many loops (or as much real estate). Dave H. Central Illinois Modeling the 1970s era Peoria and Pekin Union Railway in N-Scale
If your into building a helix you might consider a double track helix. By doing this and it works fantastic. The iner loop starts a half turn before the outer turn so that the train will enter the inner loop from the west, circle up and proceed around the room in a westward direction, then enter the outer wrap of the helix and exit the opposite side (still westward) The key to a great helix is a good solid foundation to prevent sag, and proceed slowley with perfect track. Havent uploaded pictures yet, having a problem with the Kodak photo share? havent the foggest clue what Im doing wrong, but will figure it out someday.
I've had helixes at my earlier layouts. But you can't see the train there. Now I've a long visible ramp. My old European layout Wolfgang
John, I built a double track helix for the Lackawanna Terminal Railway (in HO), the inside loop being 33" radius and the outside 36" radius to account for the overhang of long cars. I found out through trial and error what you just said about a solid foundation. When I built it in 1990 there wasn't much written on double levels or helixes so I just went ahead and built it correcting mistakes as I went along. The helix has six loops with grades entering and leaving to ease the grade which is about 1.8% (I never did measure it). One track enters from a pennisula and leaves along an outside wall. The other enters from an outside wall and leaves on the pennisula. The arrangement means that two trains going the same direction up or down the helix are actually going in opposite directions (railroad east vs. west). I didn't plan it that way it just happened (and is really strange as you look at it). Also it means that if you are looking at a train entering the bottom of the helix from the pennisula you just turn around and the train will exit in front of you at the top of the helix and vis versa. The only problems I have had is flexing of the wood structure causing problems with stability but as those were corrected the helix became very reliable. Steve
Wolfgang! I feel like I know you, from having spent some amount of time facinated with your web site, long before I became active here on Trainboard. Thanks for this new picture, I must revisit your site, I have it bookmarked. Best regards, Joe Baldwin (aka Diligentman)
Thanks Dave! More than I hoped for! Dave H. Thanks for the wonderful information. I have seen the picture of your Helix on the images before, but frankly had no idea it was a portion of a helix! I thought it was stacked trains around the outside of a room. You have given me much to think about. I have a double ended 7 track staging yard at the bottom level of my layout. (IMages posted on my images album). My first intent was to just ramp up to the next level which I have currently constructed and it is operational. However, the staging would only be 3-4 inches below the first level of the railroad. EVERYTHING I have read on Trainboard says minimum 10" space for a staging yard! So, my current design might work but would be a nightmare to maintain. I have a friend who did something similar to my current design and he says that bottom level is a plague to him, and he is a better craftsmen than most of us! Which lead me to the idea of just adding a couple of loops (helix) and I get to the 8-10 inches pretty easily with a 2%. I am using 30" min radius. Then you Dave say, make it a spiral. Well, why not! I do have the room (I think), so now I need to think that through. Better yet, I think my 3rdPlanIT has the ability to draw the spirial for me (Never thought about what it was until your informative note.) So, after Church this morning, and before I touch that new piece of 3/4 plywood, I'll do some additional engineering. I was thinking 1/2" but your rigidity comment coupled with something another said reaffirmed my 3/4 decision. Spirals take the joints outside the look so you don't loose the headroom either! Thanks so much for sharing, this is exactly the discussion I was hoping for on this thread. Because I like polls so much, I am going to add a poll to this Helix thread. Fun with Model Railroading is what I am all about! Best and with warm regards to all who are participating in the world's greatest hobby. JB aka Diligentman
John W: My first double-decked layout was essentially 2 dogbone track plans connected by a double-tracked helix. Schematically, the dogbones formed the uprights of a letter-H and the helix formed the crossbar with tracks Y-ing into the dogbones at either end. I could set up to run a train continuously on each level, or one train that would travel one dogbone, go up the helix, traverse the upper dogbone and then go down the other track in the helix to repeat the grand loop. Important note for anyone considering a double-tracked helix design!! Although I didn't realize it until I'd been using the helix a while, my designing the helix to rise when going in the counter-clockwise direction put the right side running trains on the outside loop. Because the outside loop is a slightly greater radius than the inside one, trains travel a little farther in each loop when using the outside track. When calculating the grade, this yields a slightly smaller grade on the outside track than on the inside track. If trains run on the right-hand side, they will be climbing the helix on the slightly lower grade. If the helix rises in a clockwise direction, the right side running trains will be climbing on the inside/steeper tracks. Dave H.
Additional spiral helix pics as examples for your consideration. These helixes are built in N-scale. This is my Pekin Helix. It was the first of the 4 spiral helixes I built on the new layout and I experimented with using just the homasote for subroadbed instead of homasote and ½” OSB (wafer board). Additionally, since this helix would be at one end of the 4’3” x 35’6” room and had a double mainline running around the outside of the helix footprint, I had to get my 6 loops in a maximum diameter of 42.5 inches, so I made each loop 1 inch wide instead of 1.5”. Due to the weakness of the homasote, I had to put in 16 supports instead of the 8 that I had originally thought would be sufficient. Smallest radius is about 15” for the start of the 1st (bottom) loop but increases to about16” by the 2nd loop, and the largest radius is about 21.5” at the end of the top loop. Total rise through the helix is about 14 inches because some of the grade occurs outside the helix on the lower level. This view is looking into the bowl of the Peoria Helix. Tracks leave the helix on Loop 2 (counting up from the bottom), Loop 4 (part of the turnout is just barely visible at the right), and Loop 5 (not visible). Five tracks leave the helix on the top loop. I put up the cardboard in the loop after a loco took the plunge. The cardboard in the lower left is a bridge mock-up where several BN and CNW tracks will leave the scenic-ed part of the layout into the helix. I used homasote and OSB for the subroadbed and each loop was 1.5 inches wide. Smallest radius was about 17” where tracks go into the helix at 48”. Top loop largest radius was about 24.5” where the tracks came out at 65”. This view from the north side shows how the Peoria Helix fits in with the rest of the layout. This view shows how the helix is invisible from normal viewing height. Haggerty Steel is located at 63”. The train that is mostly hidden behind the trees (only 4 white dots of the loco’s safety stripes and the yellow triangle /corner of a covered hopper are visible) is at 65” and is in FRONT of the hills that serve as the view block that fully hides the helix. The hills forming the view block in the background were cut from 2” thick Styrofoam. Hope these views address some of the questions a person might have about helixes and, in particular, spiral helixes. Dave H. Central Illinois Modeling the 1970s era Peoria and Pekin Union Railway in N-Scale
I have also seen a helix created with Unitrack viaduct pieces. The curves are pretty tight but if you need a helix to fit into a smaller space it's a good option.
Here's a webpage for the Unitrack oval helix: http://mywebpages.comcast.net/bl.bachman/TheNewSLF.html Based on online stores' prices for Unitrack, each loop would cost ~$55 and raise the track height 2.5".
Dave, you built a helix similar to what Mike Danneman built--his is a 'wedding cake' looking deal, tho! That tempts me to build mine similar.....
Hemi: By "wedding cake", do you mean the loops get smaller radii as they rise instead of larger? Essentially, has he turned the large bowl over? I considered that, but wanted to hide the helix from view, so I put it on the inside of the supporting structure. That way I could put scenery around the outside and still have complete and easy access to the track at all times for maintenance, repairs, cleaning, modifications, etc. If he is placing his helix in a separate room, so it is not necessary to scenic it and there would not be any obstructions to easy track access at any point around the entire wedding cake helix--i.e., he can stand comfortably in front of helix at any point and reach the track without bending--then the wedding cake helix can work just as well as the bowl. If, on the other hand, someone wants to place a wedding cake helix within their layout (as you might be doing?), then it will probably be necessary to hide portions of it to keep it from looking like...hmmm, <big grin> perhaps a wedding cake? This means: 1. scenery will need to be removed every time you need access. 2. you will need to put the cover someplace when you're working on the helix. On the floor where you'll have to constantly step over it? On the layout where you'll be at risk of damaging other scenery? On a specially built shelf under the layout that is designed to accept an awkwardly shaped access hatch with delicate parts on top? 3. If only some of the loops are hidden but others are visible (a tricky job, at best, with the limited space between successive loops), then operations will be influenced by the need to travel through the same portion of the layout at least a second time as you traverse the helix. Avoiding a double passage through the same scene was one of my givens and druthers when designing the P&PU in N. I know the double passage issue may not be a priority for others' layouts. How about yours? Some people dislike having their trains disappear for the length of time needed to traverse a helix. I see that disappearance (pun intended!) as an asset, especially on layouts where the long trains often have their locos in one town and their cabeese in another. Additionally, if I'm railfanning a prototype, it is quite likely that I will be spending a portion of my time waiting in anticipation of seeing my train. I mentally frame waiting for a train to exit a helix as similar to waiting for a train to appear while railfanning. (Works for me...others' results may vary.) Some people might opt for a wedding cake helix because they want to monitor the progress of their train through the helix. I have grown comfortable with the reliability of my helixes and don't watch trains 100% of the time they're in the helixes, but I have designed all of them so any operator can see into the bowl of the helix at any time by standing on nearby benches or stools, yet can also stand at the usual viewing height and have any view of the (non-scenic-ed) helix blocked. (See the Haggerty Steel pictures in previous messages.) This would not be possible with a wedding cake helix design with scenery hiding portions of it. Also, following a train around a wedding cake helix is only possible if you constantly circle from one side of the helix to the other. With a bowl spiral helix, you can monitor from a single spot without moving. In a way, monitoring through moving side to side on the helix instead of monitoring from one spot is a variation on the double passage issue. Do you have a link for Mike D.'s layout or pics of his helix? Could he or someone else who has built a wedding cake spiral helix post some pics/comments about that design? It is likely that there are advantages to the wedding cake helix design that I haven't presented. Dave H. Central Illinois Modeling the 1970s era Peoria and Pekin Union Railway in N-Scale
I use 3 Helixes (still not sure about the proper plural...) on my NP Stampede Pass layout. My room is pretty small, about 12 x 12 feet, so a double-deck was the only way to go. As I wanted to have a large separation between the two main levels I needed to go with a Helix. I actually constructed an additional wall to separate the visible part of the layout from the staging area. Yes, it reduced the visible layout space, but I can easily walk into the staging area for troubleshooting. I have currently 3 staging areas stacked on top of each other with number 4 under construction (Total of 19 tracks), so setting aside real estate for staging makes a lot of sense for me. Here is a view down from the highest level: You can see the helix and the wall to the left. All my Helixes are 45 cm radius, 7 cm separation, 2.25% grade. I wish I would have used a slightly larger radius: Operationwise the main helix represents the track between Auburn and Palmer on the old NP mainline: There was no significant grade, but on my layout it is the ruling grade! So I need to put more power on my trains than NP ever did on that stretch. Adding helpers in Lester becomes quite redundant, so it is done purely for cosmetic reasons. Live and learn.... Cheers Dirk
Dirk, I looked at your layout photos in your album.. WOW! Are you sure you're not from Lester, WA?? Great job! On a side note- splices in a helix are not necessary: http://www.trainboard.com/grapevine/showpost.php?p=203048&postcount=57
As my layout room is similar in size to what Dirk has, most likely I will have another helix. This forthcoming layout, I'd not wanted it. But without one, there's just no way to better utilize the space. Boxcab E50
How about 2 1/2 miles across and 1/2 mile deep, with tracks exiting through a tunnel at the bottom of the bowl?? Bingham Canyon mine near Magna, Utah. There's a prototype for everything!
