on my ho layout i am going to be useing some 4-8-8-4 big boys and some dda40x engines…and my local hobby shop told me that i needed to make a 30inch curve how do you make you make something like that?
Asta,
Use a yardstick. Drill a hole at the 1-inch mark and another at the 31-inch mark. Then, locate the centerpoint of your curve and drive in a finishing nail. Slip the hole at the 1-inch mark over the nail and use a pencil through the 31-inch hole to draw a 30-inch radius arc.
- Jeff
Tried to reply, but did it wrong (have to get used to the new method). Anyway, what I wanted to say that if you need to make a radius and can’t put your yardstick on the layout, use a tripod in your aisleway so you can get the necessary distance. I made alarger hole in the dumb end of the yardstick so it would fit over the mounting post of the tripod. Gives good results and is fast.
Ron K. P.S. Don’t forget the easement.
You should also provide an easement, instead of an immediate “jerk” from straight to the curve. It will make a LARGE difference. Move the center of the curve about a half an inch further in. Then measure about 6 to 8 inches along the straight back from the intersection with the (original) curve. Then “ease” a gentle curve between them. Flex track will usually do this all by itself; if not, use the yardstick, on edge, perhaps with some pins to hold it, and draw a line. Sounds kind of hard, I know, but it’s really quite easy and will make a major reduction in derailments and side-to-side jerking.
Also, I don’t necessarily agree with that fellow’s advice…although it depends on the loco. If it is a brass loco (big $), then he might be low…dunno about that. If he is talking $300 regular stuff, I’ll bet it would go around 22" okay, although just okay.
If you have the room, by all means generate the largest curves you can. That is a given. However, depending on the actual locos, you may get a much more satsifying track plan using, say, 26" curves.
Just a thought.
P.S. - on the floor, place a large sheet of thin cardboard, say from a laundry detergent box or a large cereal box that has been cut. Place a length of wood or string on one side, maybe even off the cardoard if necessary, and anchor it. Then, near the 30" mark from where it is anchored, hold or affix a marker and run that marker in an arc back and forth over the flat cardboard. Next, mark out the width of your track by making a second set of arcs, one on either side of this centre line that you have drawn…the first one. Cut out the track curve, cutting along the outer lines, and you have a good template for your curve.
My neighbor and I run his Riverossi Big Boy around my layout without mishap. I have 22 in radi and it actually navigates the curves better than my BLI Hudson. I was so impressed with the articulated engine idea I have a Bowser Challenger on back order. As Selector said unless it is brass you should do fine with 22 in or more. Of course the bigger the curves the better it will look. Terry
As far as what engine will take what radius, don’t necessarily believe anything except what the manufacturer says (in the specs). Even better, if you’re buying from your LHS, and he has a layout, TEST one! I’m guessing you don’t know exactly which engines you will be using, so the LHS gave you the 30-inch figure to cover just about anything. Even though some articulated engines WILL go through, say, a “perfect” 22-inch curve, they don’t do it very elegantly! And most 22-inch curves on actual layouts aren’t perfect! So unless you’re absolutely sure you can get by with less, stay with the 30-inch radius if at all possible. And whatever you use, also have an easement. You will have much less trouble!
Also not a bad idea to get radius guages for your curves (e.g. Ribbonrail–come in 15-48 inches as I recall)–these can be beneficial when you’re laying your track over your roadbed in order to keep the curve radius consistent since the roadbed will be over your arc lines at that point.
Jim
thanks for the help
Asta,
I think your mate at the LHS is not far off the mark. You are talking about big motive power.
Have a look at this site: http://www.nmra.org/standards/rp-11.html
Look at it this way (I am assuming we are talking HO):
- 30" is equivalent to 30 x 87 = 2610" or 217’6".
- I don’t know what you use in the States, but railway men at home (Australia) always talked of curves in chains when we used feet and inches.
- 217’6" is 3.3 chains (one chain is 66 feet).
- One branch line was restricted to operation of only one loco type. An 0-6-0 tender engine with bogie tender.
- Why was the line only open to one class of loco? Because of extremely tight curves and light construction.
- What radius were the tight curves? “numerous 5 chain and two 4 1/2 chain radius curves.”
Do you still want to run a Big Boy around curves too tight for a tiny 0-6-0?
However, we have to be realistic. Nobody has a home big enough to use realistic curve radiuses. In the final analysis do what you like because no-one can tell you how to run your layout. Just some food for thought.[dinner]
Here is some food for thought:
At the recent Train Show in Philadelphia, Intermountain had one of its’ Cab Foorwards running around a 24" radius curve. This is a model with authentic articulation. The front coupler was riding outside the outer rail.
I put my Branchline Pullman Sleepers passenger cars on a 36 inch radius curve and noticed that the coupler rode just above the outer rail.
Conclusion:
30 " radius curves may be the minimum you can use with these laege engines if you are going to hook them up to ore cars, even with easements.
Your hobby shop gave you some good - if slightly impractical advice - with their 30 inch radius curve for your Big Boy. Your inquiry was asking how you lay out a 30 inch radius curve. Early posts in response gave you some good advice - although I, myself wouldn’t even think of laying out any curve using a couple of holes in a yardstick much less a tripod - but then I know how to use the trigonometric keys on my calculator and how to read books which give trigonometric formulas. And I frequently wind up paying overdraft penalties because I can’t balance my checkbook. The responses subsequently degenerated into a “You can go down to as small as a 22 inch radius” theme. Well I would like to talk you out of that if you are thinking about doing so.
Railroads rated their locomotives - the curve restrictions for their locomotives anyway - in terms of degrees. That 30 inch radius is a 26 degrees, 19 minutes, .86 seconds curve - that, dude, is tight and trying to get a Big Boy around a curve that sharp would have been an excellent way of turning rail assoverteakettle. I don’t know just exactly what kind of curve factors Onion Specific designed into their 4000 Class locomotives but 5 degrees is probably a reasonable - and practical - figure. That’s 157.9 inches in HO; if you are wondering where the focus of that curve is at its located directly above the left hole in the outhouse on the farm out beyond the south forty.
Obviously you ain’t gonna be able to afford a 158 inch radius curve - if your layout room were that big you wouldn’t be buying plastic-boilered locomotives - most of us wish we had that kind of room - and I will if I ever hit the Powerball. In the meantime I live within practical restrictions (Read: Lackawampum). Railroads may have to put speed restrictions on 5 degree curves specifically for certain classes of locomotives. I belong
rtpoteet,
I’m with you. The layout I am working on has mainly 1.5m (59") radius, but in one section I had to go down to 1.1m (43") which is a bit of a worry. Just a matter of space.
But anyway, what I wanted to ask since you admit you know “how to read books which give trigonometric formulas”, could you enlighten me how to work out curves in degrees? There must be some definitions involved there. To my simple mind the number of degrees divergence from a tangent resulting from a curve of a given radius depends on where you measure the angle. In the extreme case if you let the curve get long enough the angle will be 360 degrees and it does not matter what radius one uses. That would only affect the size of the circle - it will still go 360 degrees. There has to be more to the definition of degrees specifying curves.
Thanks, and sorry I am a dummy. Betcha there’s millions more dummies out there not game to ask![8)]
All things being equal, the larger one’s mainline curve radii, the fewer degrees of freedom one will have with the shape of said mainline in a given area. At the extreme, one would only have the largest circle that one could fit on the layout.
Somewhere in the Land of Compromise lies a healthy and satisfying blend of length, shape, and affordable curvature. In addition to our delightfully big locomotive, we would presumably want to tow a train, even if a few cars purely for effect. Seeing the same apparition traverse one’s field of view control-side for the umpteenth time in five minutes, one would probably begin to regret simply using large curves for one’s mainline as the prinicple criterion in its design. So, the earnest modeler would probably want a smaller curvature that would enable that same delightfully large locomotive to offer various perspectives and views as it made its way around something more appealing than an oval or a circle. Once one gets away from those basic shapes, curves must lose their partial girths if one accepts that a second criterion needs to be addressed; a longer mainline that actually works.
So, yes, as I stated earlier, the general principle is to use the largest curves that will yield the most satisfying trackplan for what will have to run on it. For a few of us, nothing less than 60" will do. For the rest of we The Great Unwashed, something closer to 24" would be a triumph of both creativity and engineering. And our great big steamers would still get around quite nicely.
Bottom line - plan a clever and varied trackplan that balances the space requirements for the curves that one’s locomotives will best handle with other demands on the available space.
in my basement i am planning on useing a little corner about 9 feet by 16 feet and talking with my lhs he said the bogboy will work on a 24inch but for a more realisitc approach use a 30inch…now i am not very good with math…i have seen somewhere where someone had type to make a 24inch radius i belive you needed six 9inch turn pieces…and me trying to figure out how to make a 30 i get stuck… so i will try some of these thoughts
Asta,
Good luck with your layout. If that is the space you have do the best you can. What our Canadian friend wrote above is pretty much the facts of life. We all dream of great wide expanses of railway empire, but the cold hard fact is that few of us have the space we need. I am building a top story on our house to fit a 9 x 4 metre layout in. A couple of bedrooms for our girls to help justify the expansion. My wife is very good, but doubling the size of the house just to fit in a train layout might be more than she would accept.
Nine feet by 16 feet is a “little” corner? Pray tell, what is a “not little” corner??? There was a time when I would have killed wife, kids, and neighbors for 144 square feet for a layout.
The truth of the matter is that my first layout was in the basement of a house in Moses Lake, Washington in 1962. The house had suffered damage in a fire - something my wife and I did not know when we rented the place - and the basement wasn’t in too good of shape and the owner would not invest any funds in fixing it up. I had this large space but only part of it was available because my wife insisted on hanging laundry down there when it snowed which it did frequently. I only had three stripes and two urchins but somewhere or another I found an old ping-pong table and I finally got something running on a 22 inch radius oval with a Varney F3 and a few cars. The layout had very little scenery.
I didn’t know anything about building a layout - the hobby shop owner was primarily interested in alternate modes of transportation (airplanes) and there was a void of model railroaders in Central Washington. I muddled along and I get a big laugh today when I think of some of the stupid things I did in those heady days.
I barely had everything up and running when I moved into base housing in 1963. Here I had a garage but, as is probably true with so many others, it soon became clogged with “storage”; I did get a 4 X 8 set up but when I tried using those same 22 inch radius curves I had salvaged off of my ping-pong layout I discovered that they fit - but - the word is tightly. One day my Varney - my only piece of motive power - came off on the curve and hung precariously on the edge. Had it gone to the floor my model railroading would probably have come to a screeching halt there and then.
I invested in 18 inch radius curves and settled into building the “HO Railroad That Grows”, a wonderful book I found in the hobby shop; and then Uncle Sam
This is a Big Boy on 34" radius note the overhang of the boiler. The Big Boy will RUN on 24" BUT the problem is the TENDER the trucks are fixed and do not pivot !st (2) Pivot the next (5) do not. This is why the large Radius for them.
We are at 1800 sq ft with a min of 32" radius. The only way to fly for this type of radius is Flex Track. You can make a template form cardboard for that radius and all others and just put that on the table. The easement is easy when using flex track.
Been an R/C modeler for 30 plus years. Did build a 4 X 8 n-scale layout some years ago but sold it when it was done as I did’nt know how to run trains. Now going to build another layout and leave R/C for good. I have a space 8 X 5 and a-half to work with. Need a one and a-half foot walk way down the middle or coming from the front and then left for about 4 and a-half feet so I can build. The layout will be against two walls.This is for N-scale trains. Would like at least 4 towns or large business places to deliver cars to. Date will be from the 50’s and Great Northern RR. Now what do you think of all that? Used electric switchs the last time but will go with manual this time. Also purchased a like new Command 210 DCC system so I can run any direction.
Can use some help . Thanks
Interesting description of survey methods over there, thank you. Here is a description of what is done here: Since in the real world there is no convenient place for a radius pin, the surveyors use a chain of 100 feet length. The main body of the curve is defined by how many degrees the transit swings at each “mark”. The radius of a 1 degree curve is 5,729 feet, and the radius of any degree of curvature can be determined by dividing 5729 by the degrees. for example a fairly tight railroad curve is 10 degrees, and if on a grade might require a speed restriction, and has a radius of 573 feet, which scales in HO to 88 inch radius. (There is one modular group in the US that uses 88 inches as their minimum mainline radius!) I did not venture into the spiral curve easement which is a complicated computation, but a good approximation is achieved by using the sprung batten method described by John Armstrong in his book Track Planning for Realistic Operation. Happy railroading across the world!