I'll be here. I'll be checking in as I work on my own project. :happy19pb: That helix is worth a whole section of bench work, construction-wise. Great job. If you can 0-5-0 a train up and down the helix, why not put some rail joiners on there and run at least a six axle engine on it? No doubt it would work, but I might test intermittently in the track laying process. I failed to do that on some track work that was not in a helix and I wish I had checked as I went along. Great thread, BTW.
It's been a great journey so far, you are doing an excellent job and I really enjoy following your progress, I also like the humor in your narrative. Keep it coming.
And then some. There's a bunch of skills I've needed for this that I didn't get from normal benchwork construction. Good point. You'd think after all my rants on the subject I would not so quickly forget the fickle behaviour of flex track. While I was thinking about it more last night, I remembered that it is often easier to solder track feeders before gluing the track down - and you can solder to the underside of the rail and produce a neater job as well! Although neatness isn't going to matter so much with out-of-sight helix, if I'm going to be soldering rails in there anyway, I might as well do feeders at the same time. And that gives me furiously to think: Solder flex-track on curves No expansion joints on curves The entire helix is curved What's that going to do for thermal expansion? A new bonus to the oval helix: straight sided tracks mean you have somewhere to put the expansion joints! I think even in my mild climate 15m of flextrack is going to change length over a 20-25 degC change in temperatures So it looks like my new plan will involve soldering feeders to each track piece first, then fitting in place, soldering the joins (with the track straightened around the join), gluing, testing and fiddling while the glue is still tacky - up to and including my nominated incline warrior (the Southern Pacific SD70M from Athearn, one of my last 6-axle DC engines) and finally leaving the glue to cure while working on the next segment. I don't think I'll worry about expansion joints yet, although I may come back in 3-5 months and slice through the rails on the straight sides on one or two loops
helix: 40% track laid Okay, after trying to do it all, I've decided not to solder track feeders yet. Too much fiddling for one day. As it was I only got about 40% of the helix done. (5.5 loops * 8 segments + misc entry and exit paths = 47 segments of 1/8 of a loop. I've done 18) Tools, tools, tools Soldering iron, solder, liquid flux, file, rail joiners, rail cutters. Pliers, Tweezers, Wire strippers, Wire cutters, wire, spade lugs, crimp tool. Throttle, Engine, Track. Pencil, ruler. Glue gun, Little bits of wood to spread glue. I've got track laid from the yard ladder to the second full loop on support #2; and then took a break to do some serious rail testing - using the two longest cars I could find and the two tallest - Passenger cars and Double Stacks respectively. A bloody-nose SP SD passing under the Support #2 overpass. Support #1B in the background, and you can see the first two levels above the engine have track down. And it's probably a good thing I started testing, because I found my first problem pretty quickly: Double stacks are too tall! Crossing under the Support #2 overpass for the first loop, the clearance is a little too tight, and a double-stack clips the next loop. I knew this was the bottleneck, so I just need to work out how to fix it. I'm thinking.. Powertools. Absolutely no problems with sideswiping supports all the way up - my notched supports have handled that nicely. But another small problem occurs trying to back a train down the spiral: My first runaway! (Well, actually the third or fourth. I was too busy trying to stop the first for tourist shots!) Backing a train down the helix, about Support #6 on the first loop (and again on support #4, I think), the curve is just tight enough to pop the couplers and away she goes! Interestingly, the about 13.5" radius curve around there can actually slow these 70+' long cars to a halt on the 2% grade. So a shorter wagon may not pop the coupler, but if it did would run away faster / further! Not actually sure what to do about that one. Running engine-forward down the helix works fine and is the intended pattern (I doubt the ability of a train over about 5 cars to back down a helix without derailing or reverse-stringlining anyway). So I'm considering just posting a rule stating "no backing trains down the helix" I might test shorter cars / engines to see how problematic this actually is. The question now is: from an engineering standpoint, is it worth spending effort to try to fix a problem that only occurs under improper use? Typically the answer depends on how bad the problem is - how dangerous are the results; in this case the risk is wagons taking a four-foot trip to floorsville - versus how much effort to fix it. Can it be fixed? On the upside, laying track is something I can do after work, so I don't have to wait until the weekend for more work on this one!
Before getting too ambitious with the power tools, you might try to loosen the ramp on the supports to either side of where the stacks are hitting the ramp and shim the ramp up above the support about 1/8 to 3/16 inch. This will increase your grade for 1/4 of a loop just before it crosses the lower track and decrease it for a 1/4 turn after the ramp crosses the lower track. Net result: enough clearance to clear your double stacks without a giant increase in steepness of the entire grade throughout the length of the helix. If it is not possible or convenient to loosen and lift the ramp where it crosses the lower track, can the clearance be obtained by lowering the lower track...maybe by carefully shaving 1/8 to 3/16 inch from the top surface of the Woodlands Scenic Foam Incline? (Depending on how you secured the track to the foam, this could be much more hassle than it's worth, because you will have to separate the track from the foam and carve the correct amount away in a perfectly graduated manner for about 2 feet on either side of the under/overpass. VERY tough to do because you'll be working with little to no elbow room for maneuvering knives or hotwires.) If you have to resort to power tools...consider shaving the underside of the upper ramp. It looks like it is formed from a piece of plywood that has 3 layers. If you patiently cut the bottom layer with a small modeling saw, you could then split the lower layer off from the top two and obtain about 1/4 inch more clearance. If done carefully, you wouldn't even need to uninstall any track on either the upper or lower ramp. (I'll try to link a pic in my Helix album showing how I did something similar on the Kellar Helix.) Is the uncoupling caused solely by the tightness of the curve? Or is there perhaps a slight twist to the track along its length or a change in grade causing the couplers to mis-align? I found that when trying to clear the supports on the 1 inch wide ramp of the Pekin Helix, I had become careless in how smoothly I reduced the curve on the tightest ramp/curve. By not making my lowest loop/curve precisely decreasing, I had some places that were straighter than intended and (to make up for those errors ) other spots that curved too fast/too tightly.
ppuin: Thanks for the suggestions. First experiment I tried was lifting some track. This liquid nails is good. Too good; my chances of lifting and re-using rail is pretty slim. I may want to rethink how I'm holding the track down! Looking at the corner where it uncouples; yes it does look like I've changed radius a little too sharply - not at the point of the uncouple but shortly uphill and shortly downhill of there. Problematically, there's no 'slack' in the system at this point - if I could lift the track and move it out in radius, it would increase in length very slightly; that increase in length has to come from somewhere but all the track is glued and soldered. I see an "expansion break" on the straight section nearby coming up! Looking at the minimum clearance point, it occurs to me that all bowl / stadium helices will have to pass under a minimum radius loop at their base in order to "escape". Given a gradient of 'g', a clearance of 'c', your least radius 'r' can be found by Code: r >= (c * 100 ) / (g * 2 * PI) Which is the point at which a circle of the given radius at the given gradient will climb the given clearance. For my NMRA gauge at 43mm or 1.7", this is about 342mm or 13.5" My least radius is 13", which means I'm going to have trouble ppuin: You might want to include that calculation in your spreadsheet / blog to warn other constructors! (addendum: I didn't factor in ovals there. Umm.. "straight length * gradient / 100" should give their contribution in height. And there's two of them... "straight length * gradient / 200". My helix with 100mm straights offers 1mm of extra height.) So my options are Lift the first loop to increase gradient slightly and provide clearance Would work, I designed the spiral to be screwed down from above so it could be adjusted. But some idiot glued track across the screws! Lower the approach ramp slightly to increase gradient slightly and provide clearance Not going to be easy, lifting rails, sanding down the foam, putting rails back, all in a limited work space environment - least favoured of the options Very carefully take out one ply of the laminated timber Do-able. As noted, this is 3 ply, so removing one lamination should only weaken it significantly. Actually, it might be possible to make enough clearance (only need 2-3mm) with just taking a rasp to the underside of the ramp at that point. So it looks like it was a good idea to stop about halfway in - far enough to find the problems, and not so far that the cost of repair / replace is prohibitive.
Taking tools to the first loop clearance problem, my surform rasp doesn't fit! And it's pretty tight for my razor saw too! Some careful sawing and then using a mud-slinging spatula as a lever (I should really buy a chisel), I managed to de-laminate one ply of the spiral. | | (click to enlarge) The gap is still not high enough to allow my NMRA gauge to pass, but it does let a double-stack past, which is good enough for me (and I'm not sure I'd be happy weakening it any further). Also dealing with this section of the helix, I remembered that there's supposed to be a rerailer here, to help wagons coming careening down the spiral at Mach 2 either stay on the rails or leave them completely; before running into the yard ladder points. To fit it now would mean tearing up a fair bit of track and relaying it, so I'm not all that keen just now. Looking at the uncoupling patch a bit more closely, I've learned a few things more: The engine has body-mount couplers The wagons are all truck-mount Turning the engine around changes the behaviour Straightening the rear coupler in it's pocket changes the behaviour Coupling a short covered hopper between the first long car and the engine doesn't uncouple backing down - it derails going up instead! The problem in the main is still that the curve is so tight that both couplers swing to the outside of the arc. Depending on how the body is fitted on the loco, there's some vertical interplay as well. If a coupler hits it's sideways limit, the wagon is likely to derail. Depending on the coupler tolerance / design, at some point before the sideways limit it may uncouple. What I should probably do next, logically speaking, is try different combinations of engine and wagon to find which combination misbehaves the greatest and/or determine just how much of a problem it is over the whole fleet - i.e. can I get away with saying "loco X cannot be coupled to wagon Y". But even with my modest fleet of wagons, that's rather a large task. So I'd be tempted to just try to rip that section up and try again. Less scientific but more action-oriented.
helix: 66% track laid Interesting. After filing down the track joins around the derail points, it behaves better. If you take the curve at 30-40% throttle instead of 10-20% it behaves better. (I suspect that at 60-70% throttle it'll fall off the tracks - every trend has a limit!) So I've gone ahead and laid more track To do my best to guarantee the luck of Murphy, my helix now also has a transition from code 80 to code 55 - since the main deck is/will be C55, this has to happen somewhere. My double-stack cars seem to have deep flanges and so aren't too impressed by that! Otherwise, I've got track all the way up to loop 4 of support #7; 31/47 of the helix, or 66% complete. At this height it's starting to get uncomfortable trying to solder standing on the ground - I might need to find a stool so I can look down on the outside rail to keep doing a good job. My ankles and back are also trying to tell me something - probably that I need to lose weight. So, either I push on and finish the helix tonight; or take a break and it doesn't get done until next weekend.
helix: 96% track laid Using a chair in lieu of a stool (my knees hate me now) I've completed the last two loops of the helix; including the turnout on support 1B. This just leaves the spur that comes off the front of the helix and the actual main deck exit, which can't really be finished until there's a main deck to exit to! Until then I don't know exactly what alignment is needed. Some photos taken at 87%, showing my test train all the way at the top of the helix, almost at the turn out, 3/4 of a loop from the very top exit. Since I took these I've laid track from the left of that turnout around to the caulking gun. ... Here's @96%: It's very hard to get (unblurry infocus) high-level aerial shots like this. Yes, this is definitely a bowl / Stadium Helix. So, what's next? The helix still needs track feeders. I'll probably go with 1 or 2 per revolution If I build a main-deck mock-up, I should be able to finalise the helix exits I really should run more engines and wagons up and down the spiral to find flaws in the trackwork. All that clutter could be tidied up After that, I can look at Making 'Mount Scenery Block' to hide the helix from view Making the Main Deck, so I can actually run trains Looking in earnest for an N-scale duck (or three) for the main deck
Looks good. :thumbs_up: On the missing rerailer at the bottom of the spiral...you can build your own "rerailers" by using 0.25 inch wide strip styrene. The height should be about 0.10 less than the height of the rail. On a curve, just cut 0.75 inch long pieces and fit them together. With a little practice, you can cut them so there are no gaps as you create the rerailer curve. Good formula for the minimum radius based on clearance and gradient. I was told to use 1.75 inches vertical clearance for all trains of all types. I was told that would allow double stacks to pass; I see NMRA uses 1.7 inches. Good thread for the practical application of the ppuinn helix formula.
DIY styrene rerailer sounds better than carving up the track :tb-biggrin: Might experiment with something for the helix-base rerailer that can slow runaway cars without derailing them. I keep thinking of Hump yard 'retarders', but I suspect that's not going to fly at 1:160 (or worse, it'll fly alright - four foot flight to floorsville) Just took a 15 car "mixed" freight up the spiral and back down again! This train is slightly over half a loop of the helix, and the solitary engine was working just a little to get there But it didn't derail or uncouple or string-line around the curve (amazingly, I can back into the yard through the S-bend at the throat with half the train still on the helix. If I'm going slow!). Only issue was having to slow down on the code 55 so I could listen for any possible issues over the sound of the pizza cutters bottoming out. I see a low-profile swap-out in my future. At just on 5' long (without engine), this is about the longest train I would run on the layout; so since it can get up the hill I guess I'm set. And now I really should go to bed - I have work in about 8 hours time.
I'm still here, somewhere. Been ultra-busy++ at work past few weeks. Also been trying to find a little blue turntable for them there Google Challenges. Running more trains up and down the helix, 17-18 cars (about 2/3 of a full circle) is really the limit for the SD70M before it starts to spin wheels. Two 50' boxcars coupled starting at the top of the helix and let go will handle the yard ladder okay, rolling to a stop halfway down the yard. They roll nicely for the first three laps and then start 'singing' for the last lap and a bit. I suspect three cars would actually derail on the last lap or the start of the ladder Interesting.. No mention yet of my first-ever tortoise install (at the top of the helix). It works after some tuning, although the roadbed is really too thin for the thing (the mounting screws have run through the subroadbed and hit the turnout!) Spent most of this afternoon measuring up the main deck area so the trains will have somewhere to go once they climb the mountain. If I make the main deck out of boxes about a foot deep and about 2 feet long, resting on permanent framing - just like my staging deck, I'll need three boxes along the back wall; as well as some way of bringing the BN line forward to meet the helix front. I might tack that line to the permanent framing and make the boxes removable - just like my staging deck. Turns out after all my hard effort the main deck is 7mm too high coincidentally the thickness of the plywood. So I'm thinking a 1/2" of foam on the main deck will allow negative-elevations (like, say, a River. With ducks.) as well as fixing the height issues. This does put the tracks higher than the backdrop; but the framing stays lower so it'll handle the curved backdrop corner okay. Also need to put some more thought into how to hang scenery over the helix to complete the illusion of a tunnel punched into the mountainside. I probably need to build a light shell (plaster and/or foam) hanging from vertical poles which will have to be anchored to the helix supports and should also anchor to the upper most shelf ("lighting deck"), and paint it all mountain colours. Time to pull out the holiday snaps of Arizona! (I should have a couple of Mt Lemmon at least) Alright, enough with the rambling on here, and back to my little paper plans!
One-half inch is sufficient for some stream types in N scale. You can put the water surface right on top of the plywood. Also, you can remove short portions of the benchwork out for a few inches (cm) to make a small canyon or other type depression.
1/2" should be about 80" or 6 and 3/4 feet in N-scale. That's enough for a reasonble-height bank. I'd already considered lowering the height of the permanent framing in front of the window by about 18mm (thickness of a modern dimensional timber "1" here-abouts). This would lower the main deck box by the same amount, and give me more like 15 and 3/4 feet of bank right where the railroad crosses the river. If I change the dimensions of the box I could scrounge even more; I just have to work out how to bridge track across different height boxes on the ends of each transition point. (much like how the helix support base is not the same height as the staging deck boxes). Progress for 21 June 2008: I've managed to accurately determine just where the shelf brackets are by the simple expedient of taking a correctly sized piece of wood, sitting it on the brackets and then drawing them in. This means I've got my framing cut and braced at about the right places. /\ Probably can't see holes for more cross-braces predrilled /\ Look real close around white metal bracket to see pencil mark outlines. Of course, having a main deck will make the staging deck shadowy: So it needs some lights: That's 50W of fluorescent tubes about 235mm (9+") over the deck. I may have to experiment a bit more with how to work in the tubes better - for example, the right-end ladder (California Ladder) will also be overshadowed by the main deck, and I have no idea yet how I'll light that one. More tubes and more wires most likely. Tomorrow I'll start looking at trying to cut and install timber of the right sizes for framing between the deck and the helix (the so-called "BN line")
Progress for 22 June 2008 : Mount Helix Okay, worked on the framing a bit more; started with clamping timber out into thin air so as to try to get some accurate measurements of Helix Support #8 and where it fits relative to the deck. The result being two angles under the "BN line" from the helix to the deck, closely mimicking the staging deck below. There's one more board across the spur sticking out that finishes the corner. Everything is screwed together and the order matters - now that it's all together, there's no room for a screwdriver between much of the framing! So that's the permanent framing done for that end; I'm still not decided on if the BN line should get a box all of it's own, or if the line should be tacked to the permanent framing until it reaches the back which will be removable boxes. Next I can start looking towards the window-end. As a distraction I also made a Mockup of 'Mount Helix' - the scenic block for the helix area. Some day there will be a giant hollow-shell mountain there; which on an otherwise flat desert plain, both BN and ATSF drove straight into and punched tunnels through. She don't look like much today, but I tell ya, a few decent supports, some cardboard criss-crossed supports and Et Voilà: The Duck River Interchange. (River to the right, BN line left in front of the mountain, ATSF behind the mountain.) I've also spent a little time moving my home PC/workstation to Linux - hence the debian logo on the monitor. Got JMRI working (finally!) as well as RTS so I can check my track plan. My last two posts (and all the photos thereof) have been Penguin Powered. Och, it's soo much nicer over here.
Progress for 28 June 2008 Added the main deck supports across the window and towards the closet.. Err, I mean east from Duck River Interchange towards Kansas; including the future site of at least one duck river bridge.. Look closely behind the curve of the backdrop. In order to screw the timber together, I actually needed a 2' extension and the drill was above the backdrop! As it was, I only managed to get "most" of the screws in place. Note the left end has the cross beams above the long supports ('stringers') while the middle has the cross beams between the stringers. This claws back 18mm for lowering the main deck. Note the right end is being held in place by a clamp! I'll look into fixing this, but not just yet, as I have to figure how to get a swinging gate across from there to the bookshelves; so I keep access to the closet. Typing of bookshelves, my handy spirit-level tells me that while my supports are level, they are not at the same height as the shelves! So either the shelves get a change of height (again) or I build a ramp across the window (giving me even more height over the Duck River). | Let there be light! Fluorescent strip so there are no gaps / hot-spots. 16W over each ladder and 2x 20W along the main yard deck. 72W of light for the staging deck when the main room lamp is only 18W? Okay, maybe it's too much, but at least it looks good!
So, what's next for my little slice of the Western United States? In no particular order, I need to: wire the main deck buses build boxes for the main deck interchange lay track for the interchange Run Trains! build boxes for the line east towards the closet lay track towards the closet Run Trains! build a swinging gate across the closet lay track on the bookshelves Run Trains! Rig a fascia for the permanent main deck framing Rig a fascia for the staging deck boxes Rig a fascia for the main deck boxes Finish wiring the helix Scenic the helix Scenic the interchange Scenic the line east towards the closet (ooh! bridge!) Obviously at various points I get to run trains; but I may well be months away from actually being able to run from the staging yard all the way up out across around and then back again. Well, everyone needs a hobby. PS. winter has finally arrived. :rain: brrr.
Worse, I've met a girl. :in-love: So between work and that, I've got no free time left for the layout. (Wow, nearly 3 months without posting?)
Ok... so we will have to wait untill the novelty wears off or you come back down to earth:tb-wink: Great news all the same, only hope that she is supportive of your hobby (you have told her, right?)
