How to add a broad curve (>22") to handle a 6-axle loco in a corner of a U-shaped HO layout? I know that the max curve on a 2x8' of foam board is 22" in HO scale (per http://www.layoutvision.com/id62.html). I'd like to put in a 24" HO curve that doesn't need to go 180 degrees but have a slight curve before leading to a yard. Plenty of layouts have curves on u-shaped designs with curves far broader than 22".
Thanks,
Lee
kasskabooseI know that the max curve on a 2x8' of foam board is 22" in HO scale (per http://www.layoutvision.com/id62.html).
The diagram on my web page doesn't seem to have anything to do with the situation you are describing ... and/or you are misinterpreting that page. Or I am misinterpreting your question.
[In any case, a 180° turnback curve on a 2-foot-wide piece of benchwork would be more like 11" radius. (Some folks confuse radius and diameter.) ]
But that's not your situation, apparently. If you are talking about the L-shaped corner of a U-shaped layout with 2-foot-deep benchwork, the curves can be pretty broad, but that starts to “use up” the straight track on either side of the curve.
A diagram of what you are describing would help others help you.
kasskabooseI'd like to put in a 24" HO curve that doesn't need to go 180 degrees but have a slight curve before leading to a yard.
Should work fine. I think if you draw it to scale you'll see. But again, I may not be understanding what you are asking at all.
Byron
Layout Design GalleryLayout Design Special Interest Group
If you curve the inside facia you can make the curve as broad as you want.
If you have square inside corners the the largest radius you can have is roughly equal to the smallest width of either side less the distance from the back to track center less 0.707 times the distance you want on the inside corner to the track center all divided by 0.707.
R=(W-a-0.707b)/0.707
where:
R= radius
W= bench width
a= distance from backdrop to track centerline
b= distance from inside corner to track centerline
For example if you have a 24 inch bench and want to have the track six inches from the backdrop and two inches clear on the inside corner, the maximum radius is R=(24-6-0.707*2)/0.707 = 23.46 inch. If you place the track four inches from the backdrop you could use a 26.29 inch radius.
Ray
I'm not sure that I completely understand your situation, but a quick check using a tape measure in my layout room shows that a "U"-shaped layout with all three sides 22" deep will allow a curve of at least 48" radius at both sides of the base of the "U", but that is somewhat dependent on the total over-all width of the "U" (or the aisle width between the two sides).It will, however, eat-up a lot of real estate that might be put to better use. In the photo below, the two tracks at left are 36" and 34" radius, and the layout depth of 22" (left-to-right) occurs just above the truck parked to the right of the large green structure located about mid-frame.The portion of the layout in the distance and also out-of-sight to the right, is deeper than 22", simply because the space was available, but the near side of the inner track is only 18" from the wall where the curve ends at the right side of the picture.
If this were one corner of the base of your "U"-shaped layout, those curves would be completely do-able.
Wayne
While I always draw scale diagrammes to show the feasibility of what I want to have for trackwork, I am a visual guy who likes to see if for proof of concept before I start up the circular saw and start cutting 1X4 clear spruce lengths. So, in the space I have for the layout, I use 1" masking tape, the cheapest I can find, and begin by laying out the edges of the benchwork. Then, I use the same tape and lay out the curves using an accurately drilled trammel, depicted turnouts (accurately, no fudging with turnouts!!), and the tangents. I lay out the yard to ensure I can get the numbers of ladders tracks I want, and leads off the turntable and into an accurately represented roundhouse.
It may sound like a lot of bother to some, but for me, standing and looking down at what I see helps me to feel secure that I can close a loop without disappointing compromises to my minimum radius standard, for example, or having to use a #5 frog instead of my preferred #6.
You probably don't need, or want, to do this, but you could always try it for the small space in that corner you're trying to negotiate. Just mark out a corner, accurately, and make yourself a trammel...it's easy with 48" lengths of lath. Then, with the one end securely anchored so that it pivots in one spot, mark out the curves you hope to generate. You might be surprised to find that a 24" curve does a lot more for your grand plan than a 26" curve, even though the general rule is to go wide on curves when you can.
T'is a thought.....
This is on 2' wide pieces (the whole layout is an 8x12 donut, but the point here is a 90 degree turn). Outside curve is about 32" radius, second track is about 30" radius, and the track where the loco is on more like 26" radius. And still there is space inside and outside the tracks. The drawn lines which was were the engine service area was going to be look wider than scale because I was using Woodland Scenics roadbed which unlike cork is one piece so this is the outer edge of the ballast sholder, which is signifcantly wider than HO track gauge.
This layout was the first (and LAST) time I actually traced the plan (output from 3rd PlanIt). To draw in curves on my last layout, especially in the corners where I couldn;t go outside the benchwork, I took a piece of 1x2, drilled a hole to fit over the stud on my camera tripod, and then drilled other holes at various radii distance from that pivot hole. The tripod allowed me to set the pivot end of the stick exactly level witht he top of the benchwork, and then I moved it around to get the right distance from the edge of the benchwork at both the start and end points of the curve, stuck a pencil in the hole, and traced out the arc. Used a straight edge to sketch in the tangent track, slightly offset to the outside of the curve, to form an easement.
BTW this is the pic I needed for a different thread. You can see a connection drawn to a track outside of the first main, leading towards the boxes stacked by the wall. Under the main, and on the drawn in part where there is no track, you can see some masking tape. Originally, I had turnouts in those locatioons - the masking tape holds plugs of foam covering up the holes where the Tortoises were. Both turnouts were removed and reused elsewhere - this track was all caulked in place. The foam roadbed didn't come off cleanly, but the track did, and a pair of expenseive (relatively) turnouts got reused with no problem.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker To draw in curves on my last layout, especially in the corners where I couldn;t go outside the benchwork, I took a piece of 1x2, drilled a hole to fit over the stud on my camera tripod, and then drilled other holes at various radii distance from that pivot hole. The tripod allowed me to set the pivot end of the stick exactly level witht he top of the benchwork, and then I moved it around to get the right distance from the edge of the benchwork at both the start and end points of the curve, stuck a pencil in the hole, and traced out the arc.
To draw in curves on my last layout, especially in the corners where I couldn;t go outside the benchwork, I took a piece of 1x2, drilled a hole to fit over the stud on my camera tripod, and then drilled other holes at various radii distance from that pivot hole. The tripod allowed me to set the pivot end of the stick exactly level witht he top of the benchwork, and then I moved it around to get the right distance from the edge of the benchwork at both the start and end points of the curve, stuck a pencil in the hole, and traced out the arc.
So you made a trammel and adapted it to a camera tripod. I like that idea. On my last layout, I drew out my curve centerlines almost exactly the same way, except I would, where necessary, temporarily attach a long piece of wood to the layout to afix my trammel, and then adjust the pivot point to align it with both points the curve would meet each tangent it would connect with, but at a point about ahalf inch inside to allow for easements.
I like the tripod method of the pivot point; U think I still have my old tripod, so Ill have to remember that trick next time around.
Used a straight edge to sketch in the tangent track, slightly offset to the outside of the curve, to form an easement.
yep. Did that prior to drawing in my curve centerlines. I would adjust the trammel pivot point so the curve centerline would match with that predrawn line offset from the tangent, making easements easy to lay.
Rio Grande. The Action Road - Focus 1977-1983
Thanks for the helpful suggestions. The ideas given make it seem that having a broad curve is easier than I thought. Having a broad curve in a corner is a challenge to avoid over-reach.
The pictures given greatly help being a visual person. One (of many) lessons learned I plan to use on the 2nd layout is having the entire layout easily reachable.
The dremmel idea is solid, but I vound the string, sharpie, and thumbtack works well for me to draw a curve. To each their own, I suppose!
Best,
rrinker This layout was the first (and LAST) time I actually traced the plan (output from 3rd PlanIt). To draw in curves on my last layout, especially in the corners where I couldn;t go outside the benchwork, I took a piece of 1x2, drilled a hole to fit over the stud on my camera tripod, and then drilled other holes at various radii distance from that pivot hole. The tripod allowed me to set the pivot end of the stick exactly level witht he top of the benchwork, and then I moved it around to get the right distance from the edge of the benchwork at both the start and end points of the curve, stuck a pencil in the hole, and traced out the arc. Used a straight edge to sketch in the tangent track, slightly offset to the outside of the curve, to form an easement. --Randy
I used a yard stick that had holes drilled at the 1" marks.
riogrande5761....On my last layout, I drew out my curve centerlines almost exactly the same way, except I would, where necessary, temporarily attach a long piece of wood to the layout to afix my trammel, and then adjust the pivot point to align it with both points the curve would meet each tangent it would connect with, but at a point about ahalf inch inside to allow for easements....
I did something similar when laying-out the curves on my layout, but because I was trying to fit in the widest curves possible and was not working with a trackplan, the board extending out into the aisle from the corner, meant to support the fixed pivot-end of the trammel, was fashioned in a manner that the attachment of the supporting board could also act as a pivot point.This allowed me to vary the starting and finishing points of the curve to better accommodate the track beyond the ends of the curve. In some cases, I continued the curve further than originally intended, towards the aisle, then put it directly into a reverse curve to angle the track somewhat so that it wouldn't be parallel to the fascia, yet still keeping it towards the foreground of what were not-very-deep scenes.
In the somewhat distant photo below, I'm not sure that it will be apparent to those not familiar with my layout in person, but the curves coming out of both corners carry the track towards the aisle, moreso on the right side than the left, but then drift away from the layout's edge so as to be not parallel to that edge.
All of the layout's curves were layed-out first, with a vision of the scenes which I wanted to create reasonably well-formed in my head. After that, it was fairly simple to join the curves with straight-ish track, and add industrial tracks where they'd fit-in best.
The thing is, if you are drawiing an inside curve on a shelf layout, where to you pivot the stick or sting from? That's why I use a tripod.
I was going to use a yardstick, but I didn;t have one handy. They don't give them out like they used to back in the day. Plus the pivot point can't be a 0, you need to allow some 'meat' for the pivot hole, so the markings will be an inch or so off. I did have a scrap of 1/x cross brace material so that's what I used, measured my distances from the pivot hole and write them on the stick. A string should be just as easy, if a bit harder to secure to the tripod and fussier to measure out to wrap around the pencil at the correct radius. Remember a string has to turn, not start wrapping around the center or you will create a decreasing radius spiral, not a fixed radius curve. Someone who really loves math can probably figure out the diameter of center spool needed to allow the string wrapping around to create the spiral easement but the tangent offset method combined with flex track that actually flexes automatically forms a reasonable easement.
rrinker The thing is, if you are drawing an inside curve on a shelf layout, where to you pivot the stick or string from? That's why I use a tripod...
I had a tripod, but never thought to use it. I simply fastened a length of 1"x2" to the open grid benchwork using a nail. The board projected out from the corner and into the aisle.
rrinker...I was going to use a yardstick, but I didn't have one handy. They don't give them out like they used to back in the day. Plus the pivot point can't be a 0, you need to allow some 'meat' for the pivot hole, so the markings will be an inch or so off. I did have a scrap of 1/x cross brace material so that's what I used, measured my distances from the pivot hole and write them on the stick.
Rather than use a yardstick, I had some 1/4" plywood that I cut into narrow strips then drilled two pivot holes, one an inch from the end and a second one 1" in from the first. I then measured out 30" from the first pivot point, and drilled a pencil-size hole, and more of the same, on 2" spacings, out to 38". Using the first pivot point gave me even-numbered centreline radii, while using the second pivot point gave me odd-numbered radii. Regardless of which pivot point was used to determine the centreline radius, the other served to give the inner and outer radii of the 2" wide 3/4" plywood sub-roadbed.I also made a longer one in the same manner, but started drilling the pencil holes at 38" and went up from there.By allowing the board, on which the pivoting "yardstick" was mounted, to also pivot, the position on the benchwork of the desired curve could be altered, much as you would do by moving the tripod.
The more difficult curves to determine, for me, anyway, were the two outside curves needed to get around my oddly-shaped layout room. I'm sure that there's some suitable mathematical method, but it never presented itself. Instead, I simply took some of the pre-cut 3/4" plywood curves that I had on-hand, all marked with their particular radius, and tried them, in-place atop the open grid framework.
In the photo above, the inner curve is a 30" radius, the outer one 33".
I cut these strips out of heavy appliance cardboard. I have various radiuses starting at 30" and go up to 36" inch. They are set lengths so I can lay them end to end to add length if need be. I tend to use them more as guides just to check that I don't go under a set requirement.
I like to vary the radius through a curve if possible as it gives a less stamped out look that you can get with sectional track or what you get by following a set line. I may go into a curve with a 32" radius and open it up to a 36" radius as I go around the curve. Of course, I could get a larger radius through the beginning of the curve if I set it the same radius the whole way through, but I give that up for visual appeal. I like to make the track look like it is flowing.
As Byron said, large curves will eat up straight sections. You can compensate for this by using curved turnouts. This will give you a head start into a yard or siding.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
doctorwayne I did something similar when laying-out the curves on my layout, but because I was trying to fit in the widest curves possible and was not working with a trackplan, the board extending out into the aisle from the corner, meant to support the fixed pivot-end of the trammel, was fashioned in a manner that the attachment of the supporting board could also act as a pivot point.
I did something similar when laying-out the curves on my layout, but because I was trying to fit in the widest curves possible and was not working with a trackplan, the board extending out into the aisle from the corner, meant to support the fixed pivot-end of the trammel, was fashioned in a manner that the attachment of the supporting board could also act as a pivot point.
Yes, I did exactly that. The place where I needed to pivot the trammel was out in the isle, which is where the tripod would come in handy. But like you, I took a narrow board and attached it to the corner sticking out to the point where the povit would go, and temparily attached it to the layout with drywall screws. After drawing any necessary curve center-lines, I removed the screws and the board. But I do have a tripod so I may give that a whirl next time around.
rrinker The thing is, if you are drawiing an inside curve on a shelf layout, where to you pivot the stick or sting from? That's why I use a tripod.
Answer if you don't have a tripod, temporarily attach a long piece of wood to pivot form. I did this on 3 different layouts - it does the job well too.
I was going to use a yardstick, but I didn;t have one handy. They don't give them out like they used to back in the day. Plus the pivot point can't be a 0, you need to allow some 'meat' for the pivot hole, so the markings will be an inch or so off. [/quote]
Home depot or Lowes have yard sticks for one dollar each in the paint area. Of course you can use a yard stick but I'm afraid I would have a brain fart and forget that the hole drilled is not the actual number it is drilled next to and make mistakes. I took a piece wood similar in dimension to a yard stick, longer actually, and measured my own holes and marked them to a series of radii that I planned to use.
When I was a kid, we had 3-4 yard sticks that were given away free by various hardware stores and actually many different unrelated businesses - printed with an advertisement for said business, of course. Right, I could have driven to Lowes and got one for a buck, but th scrap of wood I already had and was more or less 'free' - probably could have used it elsewhere in benchwork construction.
That 'brain fart' is my second reason for not using a yard stick. Would have had to remember tha tthe hole at the 26" line really was for a 25" radius curve since the pivot would have been at the 1" mark. Not, I'm sure, a huge deal and quickly noticed and fixed, but on my custom stick, 26" was a 26" curve, no remembering.
WHatever works. For my next layout I plan to use a more open benchwork approach, putting the subroadbed only where the tracks (and structures) go, so curves will be laid out on flat sheets and cut out before being placed. I'm not so sure I will be marking out the specific center lines or just eyeballing it and then making sure the curve is smooth using templates. Or I can just trace a centerline at the same time I trace the inner and outer cut lines. Part of it is being unsure of how I want to proceed for roadbed - I really want to use the homasote stuff from Cascade but also in trying different things out, the quietest option was plywood with homasote and then cork on top. However, I prefer the more realistic shoulder slope of the homasote roadbed, plus I like the cut to the actual size turnout pads Cascade sells.
BATMAN and others,
The idea of using templates is sound for a radius. I plan on having a 26-28" curve which is quite sutiable for a six-axle loco and most freight cars. They can navigate around a slight curve before the track goes straight. The yardstick method is great but the template works well since I don't have to remember what goes where.
Is there a site that has broad curves or make my own as done by others?
kasskaboose BATMAN and others, The idea of using templates is sound for a radius. I plan on having a 26-28" curve which is quite sutiable for a six-axle loco and most freight cars. They can navigate around a slight curve before the track goes straight. The yardstick method is great but the template works well since I don't have to remember what goes where. Is there a site that has broad curves or make my own as done by others?
Nothing is more accurate than drawing out a curve centerline than using a trammel.
Curve templets can introduce some error into the radius, depending on the template and how they are used. But, you'll be in the ball park, as they say.
One template I have seen but will never use are those metal curve pieces that fit in between the rails, and force flex track to curve to their stated radius. For them to fit there will be a little bit of slop and thats going to allow the radius to get "off" from the exact radius they are marked for, and that will be compounded as you move them along and lay the curve out through, say, a 180 degree arc. I imagine you could be off by as much as an inch or two across the entire arc. Other templates may have less potential for error.
I'm very picky about my track work so prefer to use methods that yield the best and most accurate geometry possible. Templates can get the job done and be "close enough" for many.
I would think you could get any length stick, drive a finishing nail through it, then measure from the nail to the radius length, use that as a center for a drill, drill a hole just large enough to accommodate a #2 pencil, and that modified stick would be as accurate as anything. Drive the nail through the ply at your pivot point so that it is secure but allows the stick to rotate. You could even use one long stick with several holes at various radii.
Or, drill two holes for pencils to draw two lines simulating the width of track/roadbed plus clearance to have a more accurate curve by which to cut the subroadbed, instead of using just a centerline.
Not sure what the fuss is about. Then again, I paint my models on the back patio using a rattle can and a bent coat hanger.
- Douglas
riogrande5761Nothing is more accurate than drawing out a curve centerline than using a trammel.
I agree with this and should have mentioned, that if you are going to make templates out of "whatever" make sure to use a trammel to draw both the inside arc and outside arc. You can then measure between the two lines to double check for accuracy. Also if you make a trammel, whatever you stick in the hole to use as a pivot point should fit snug, any slop will also cause inaccuracies in the curve, even more than a template.
I visited a large basement layout only yesterday that had beautiful curves through a rolling "British" countryside. Nowhere was there a 180-degree curve that was the same radius through the entire curve. I mentioned this to the guy and he said "show me landscape anywhere that allows for that without moving a lot of rock and dirt first. Hard to do on a small layout, but once you get into custom made to requirements benchwork it can be accomplished.
BATMAN I agree with this and should have mentioned, that if you are going to make templates out of "whatever" make sure to use a trammel to draw both the inside arc and outside arc. You can then measure between the two lines to double check for accuracy. Also if you make a trammel, whatever you stick in the hole to use as a pivot point should fit snug, any slop will also cause inaccuracies in the curve, even more than a template.
Nowhere was there a 180-degree curve that was the same radius through the entire curve. I mentioned this to the guy and he said "show me landscape anywhere that allows for that without moving a lot of rock and dirt first.
While the Brit may have had point, I kind of wonder if he had any civil engineering training. From what I understand, railroads don't layout right-of-way quite like that. They layout arc's in even degree's - perhaps it might be series of arcs to adapt to the landscape but it's still even arcs. Anyway, doubt I'm going to go to those great lengths myself just to see if someone notices or not.
It's not the age honey, it's the mileage
Is that a good thing or a bad thing? Is it high mileage or low mileage?
I'm not sure how to read that "saying", but as long as she is happy thats what matters. ]
riogrande5761While the Brit may have had point, I kind of wonder if he had any civil engineering training. From what I understand, railroads don't layout right-of-way quite like that. They layout arc's in even degree's - perhaps it might be series of arcs to adapt to the landscape but it's still even arcs. Anyway, doubt I'm going to go to those great lengths myself just to see if someone notices or not. It's not the age honey, it's the mileage
He did work for the railroad in England, but I don't know in what capacity.
As far as the high mileage statement goes. I played hard all my life and it is coming home to roost. Lots of broken bones and other significant injuries have taken its toll. I would do it all over again in a heartbeat though.
Here is a photo showing the point I am trying to make. I have my share of stamped out 180 degree turns, however, this is one spot where I was able to change things up a bit.
On the right of the pic the curve is a huge radius that curves down to about 34 or 36 inches. Then on the left you can see the track turn slightly towards the front of the benchwork and this makes the final turn to the left about 50 or 60 degrees instead of the usual 90.
Using spline makes this kind of thing a breeze, whereas when people use cookie cutter, drawing out and cutting up all that plywood makes the added job of drawing and cutting different radiuses all over the place just more work that some (including me) decide to forgo. Like they say there is no right way when there are many good choices.
Splines seem like extra work that I can avoid, and do - I'm a little to lazy things which seem a bit exotic.
Ah, now I know what your siggy is about - since it had the hunny thing, it sounded like something you say to a woman but sometimes I'm a little slow on the uptake and need things spelled out!