You know, I was so excited for my broad 30" radius curves on the on the Francisquito Valley Railway 2.0 mainline - only to find that it's actually not that broad or visually pleasing when running an 85' superliner. The outside rail is just barely hidden and the overhang on the inside is pretty bad.
Well, figures because typical US minimum is 410 feet radius which 717 feet for mainline for long freights. My 30" is a tight 217 feet.
This would be the first of many disappointments as the track plan (3rdPlanIt) gets transferred to the real world. Ahem ... I mean my little world.
NP
Yes, in HO scale, that 414 ft. minimum translates to 4' 8-1/2" radius, and that 717 ft. "normal" curve is 8' 2-3/4" radius. Sobering, isn't it?
Tom
I have been fortunate, but mostly determined, to have enough room for curves in the 33"+ range for my last two layouts. For my second, a folded loop that I operated from a central pit, the end curves of the overall rectangular shape of the bench were in the 45" and better range, and I got hooked.
However, my equipment was a huge factor. For the third layout, now history, I had a new Sunset Canadian Pacific 2-10-4 that was supposedly good for 30" minimum radius. Were I a Greek God and capable of laying a perfect curve of that radius each time, I might have gone with that as my minimum. Instead, I used 33", a ten percent buffer for the sake of that one locomotive. Walther's heavyweights do well down to about 27" or so, so I knew they would be fine, even at speed.
Now, with that lovely experience, I will never have less than 33" for track anywhere if I can help it (barring a small industrial complex), but my mains will always be nested 36" and 39" curves, or much wider if I have the room. Things simply work better and look better.
If you look at NMRA Recommended Practice 11 (RP-11), 85' passenger cars are in category "P" for track curvature which is minimum 40" radius in HO scale.
I just found RP-11 not too long ago, and now that I have seen your post and others, I am convinced that 30" minimum won't work on my upcoming layout like I thought it would. Fortunately I am still in planning and can change things before finding out the hard way.
I've also been doing some reading about adding easements to curves, especially on track that the 85-footers will be operating on.
Jeff L
To look realistic, not necessarily prototypical, the radius of the curve in HO scale should be 3x.
So, an 85' car needs a 36" radius curve to look realistic.
To calculate, 85' x12" = 1,020 scale inches, 1020 / 87 = 11.72" (the HO scale length of the car), 11.72" x 3 = 35.2" (the required radius to look realistic).
Rounded, the required radius of the curve must be 36 inches to look realistic.
Rich
Alton Junction
Rich, I supect you are right given how the outside rail is barely covered at 30".
David, Umm. Yeah. I wish I knew prior to scratch building a curved trestle at 30" radius. It's on the main, so without a significant change to my era and theme the superliner and bombardiers will be going over it multiple times a day.
I have a 5' 6" wide area in the basement and using it gave me about 20' of main line. A 180 deg turn is 2.5' radius in that space.
Well I am sure I can live with it.
NP.
richhotrainTo look realistic, not necessarily prototypical, the radius of the curve in HO scale should be 3x.
Hi Rich,
Assuming you're refering to the same report I use...
3X is the point where everything should run well.
3.5X looks less toy like when viewed from inside the curve
4X looks less toy like when viewed from outside the curve
5X will allow reliable coupling
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
You have discovered what many experienced modelers have known for years, that Allen McCelland of V&O model railroad fame discussed this in one of his articles, that long model train cars don't look very nice on the relatively sharp 30-inch HO curves. Allen was so unsatisfied with how his Walthers 89' autorack looked, he kit bashed a shorter version by removing one of the panels, after which which he felt the shortened autorack looked better on his 30 inch curves.
I built my first sizable layout in a garage in Indiana, which was 16x19 feet and had minimum 30 inch curves, but I also put in a 36-inch curve in a central point and was running my Walthers autoracks around it, and did notice even the 36-inch curve looked quite sharp under them and the middles of the long cars really overhang on that 36 inch curve!
While I was still living in Indiana, I had attended the GATS train show in Louisville KY and watched a train full of Walthers autoracks on a modular layout and noticed how nice they looked on the corner modules curves. I asked one of the club members what the curve radii were and he answered something like 56-inches.
The lesson I have learned since then is 30, 32 even 36 or a bit more, it doesn't make that much difference for the really long cars like the 89' autoracks or 89' TOFC flat cars, the curves have to be much larger to get a significant visual benefit - like well north of 40-inch radii. So like some of our compatriots in this thread, my personal minimums on my last and present layouts are 32-inches, but really that is so I have the freedom to operate a wide range 70's and 80's era rolling stock, including long freight cars and passenger cars.
But I also know those 32-inch curves still look very sharp, and even if I could have all 36 inch minimum curves, sure, that would improve things for much of the rolling stock but even those still look sharp under those 89' cars, which I learned.
Lesson here, as usual, model railroading is all about compromise. But we can take one tip from the dean of layout design, John Armstrong, and that is to try to include some "cosmetic curves", curves of such sufficiently large radii that you can enjoy the appearance of the long freight cars on some key areas of the layout for train watching purposes. I included one such spot on my small 10x18 foot layout, where I designed a 56-inch radius curve in the middle of one side of the layout.
Cheers
Rio Grande. The Action Road - Focus 1977-1983
This was one factor in my switching to N scale many moons ago. I wanted to be able to sometimes "launch 'em and let 'em run" and even 30" curves were going to be hard to fit into the space I had, especially when I allowed for easements. That was especially a consideration because I was planning on modeling mid-40s Pennsy, mostly steam. T1s, M1s, and maybe even a J1 for good measure needed as gentle of a curve as they could get. That was when the switch to N happened.
The best "train space" I have had of three (never finished) layouts was in our last house. The space allowed me to use eased 27" curves in N. When I switched scales I also switched eras a bit, to the late 50s, so the motive power does not tax the minimum radius quite so much. Still, I have two passenger trains and the cars look better on wider curves. The current project has minimum 18" curves on the main, which translates to about 33" in HO.
We are contemplating another move, and I may get the chance to add a space for my railroad and office. You better believe I will be looking toward the 24-27" radius range (44-48 HO equivalent) if for no other reason than it looks good, especially the passenger trains.
In fairness, the current eased 18" curves have been trouble free, even with an Athearn Big Boy that makes an appearance sometimes. So reliability for my 1958 era equipment is not really hurt by the compromise. But when planning, I always run with "wider is better" for the main, and cosmetic curves sure look good. I generally design in one or more 5-degree curves (roughly 84" R in N, about 158" in HO) as an alternative to a long straight section.
Of course, using that philosophy can cause me to rethink the complexity of the plan, but I don't consider that a bad thing, either. I would compromise that philosophy pretty quickly if the available space left me room for nothing more than a simple oval, but somewhere between that and the bowl of spaghetti is my ideal.
- Mark
The original poster really needs to specify scale as the 30-inch radius title is very much tied to scale and means completely different things to N scalers vs. HO.
Just saying...
riogrande5761 The original poster really needs to specify scale as the 30-inch radius title is very much tied to scale and means completely different things to N scalers vs. HO. Just saying...
He did. You just need to do a little math.
NP01My 30" is a tight 217 feet.
When I started designing my new layout (UP north of Ogden) I started with 28" curves. However I didn't like the way they looked when I did some proof of concept testing. So I went to 32". And then 36". And now 40+". I basically ran out of real world real estate at 40" so it's going to have to do.
Modeling an HO gauge freelance version of the Union Pacific Oregon Short Line and the Utah Railway around 1957 in a world where Pirates from the Great Salt Lake founded Ogden, UT.
- Photo album of layout construction -
carl425 riogrande5761 The original poster really needs to specify scale as the 30-inch radius title is very much tied to scale and means completely different things to N scalers vs. HO. Just saying... He did. You just need to do a little math. NP01 My 30" is a tight 217 feet.
NP01 My 30" is a tight 217 feet.
Enjoying yourself there? (as my wife would say) The fact that some have come in here speaking about other scales which are unrelated to the original post, it's clear having the scale stated up front plainly would have been a good idea. But whatever...
Well, also, an 85' car wouldn't have horrible overhang if it was in N scale with 30" radius curves. That's almost a 60" radius in HO, and if your equipment doesn't look decent on a 60" radius in HO, I don't know what to tell you...
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
riogrande5761Enjoying yourself there? (as my wife would say) The fact that some have come in here speaking about other scales which are unrelated to the original post, it's clear having the scale stated up front plainly would have been a good idea. But whatever...
One person mentioned N-scale, and it's clear if you read his post that he knew the OP was talking about HO. He shared the OP's opinion of the HO-scale 30" curve and explained that was a factor in his conversion to N.
AdelieThis was one factor in my switching to N scale many moons ago. I wanted to be able to sometimes "launch 'em and let 'em run" and even 30" curves were going to be hard to fit into the space I had, especially when I allowed for easements.
LOL. Yeah...alot of us just don't always think of how the real world translates dimensionally into scale (I'm one of them). And most of us just don't have the space to accurately shrink reality. And now for another twist in the knickers. Railroads, as well as highways, the curves are spiralled. Figure a railroad curve being something a little more like a wide parabolic curve...having a slowly shrinking radius to the center of curve.
I remember reading years ago that Sand Patch Grade in PA had some curves in the order of 6 degrees...or about 955' R. Not too far from your numbers. I've often wanted to build a layout with accurate curvature...but that would take at least a small warehouse. Oh well.
Mark H
Modeling in HO...Reading and Conrail together in an alternate history.
crhostler61 LOL. Yeah...alot of us just don't always think of how the real world translates dimensionally into scale (I'm one of them). And most of us just don't have the space to accurately shrink reality. And now for another twist in the knickers. Railroads, as well as highways, the curves are spiralled. Figure a railroad curve being something a little more like a wide parabolic curve...having a slowly shrinking radius to the center of curve. I remember reading years ago that Sand Patch Grade in PA had some curves in the order of 6 degrees...or about 955' R. Not too far from your numbers. I've often wanted to build a layout with accurate curvature...but that would take at least a small warehouse. Oh well. Mark H
When I was taking drivers training way back at 15, the instructor told us that the road curves were laid out at a constant radius so that when you were in a curve, you could hold your steering wheel basically at the same position through the curve. I found that to be true most of the time right up to the present day.
Railroads - maybe a different beast? I do design in easements into my curves following John Armstrongs info in Track Planning for Realistic Operation.
carl425 One person mentioned N-scale, and it's clear if you read his post that he knew the OP was talking about HO. He shared the OP's opinion of the HO-scale 30" curve and explained that was a factor in his conversion to N.
Roads are somewhat self-eases since generally the lane is wider than the vehicle and you can adjust the turn-in so it feels comfortable (and your passengers aren't flung against the doors). Trains on the other hand corner like they are on rails (hey, wait...) so any easement in the curve has to actually be built in to the track. If you look at Armstrong's explanation in Track Planning for Realistic Operation, his "coefficient of lurch" (no, nothing to do with the Addams family butler) is less for 18" radius curves with an easement than it is for 24" radius curves without (in HO). The same car or loco will LOOK better on the 24" vs the 18", but the 18" with easement will give better operation - and take less space.
Automobile turns are necessarily eased due to the decreasing radius from tangent movement to the best-fit until the radius begins to increase again to the next movement along a tangent path. IOW, you are driving straight, you commence a turn, even a tight street or driveway entrance, and you are turning your steering wheel. With each arc of steering wheel movement, your tire path radius begins to tighten, meaning it is essentially an eased curve.
Good discussion on Automobiles vs Train easements. That's something new I had not thought about.
rrinker Roads are somewhat self-eases since generally the lane is wider than the vehicle and you can adjust the turn-in so it feels comfortable (and your passengers aren't flung against the doors). Trains on the other hand corner like they are on rails (hey, wait...) so any easement in the curve has to actually be built in to the track. If you look at Armstrong's explanation in Track Planning for Realistic Operation, his "coefficient of lurch" (no, nothing to do with the Addams family butler) is less for 18" radius curves with an easement than it is for 24" radius curves without (in HO). The same car or loco will LOOK better on the 24" vs the 18", but the 18" with easement will give better operation - and take less space. --Randy
Yes, thats right out of John Armstrongs Track Planning For Realistic Operation book - I still have mine which I bought in the 1980's and it's well worn. I dug it out of storage boxes to refresh my memory when starting my layout last year.
Basically I use an offset of approx. half inch when making easements on 30 (or in my case 32) inch curves - it's not 100% dead on per his table but pretty close. One reason I like using Atlas flex track is it is springy and it naturally springs to the spriral easement if I use a few points marked as references at the start-point (from the straight tangent), mid-point (off-set) and end-point (where the spiral meets the fixed curve radii).
These in-progress photo's of the staging yard show the straight to curve areas - all were laid with easements:
The staging shown above is now covered by a 2nd level here - also these curves are laid with easements: So basically it's only eating up roughly a half inch (give or take) of extra space to add in the easement; so moral of the story is you don't necessarly have to choose between 18 and 24 inch curves. If you can fit a 24 inch curve in to your space, it's not that much more space needed to add in the easement, unless you are in a very tight spot.
The staging shown above is now covered by a 2nd level here - also these curves are laid with easements:
So basically it's only eating up roughly a half inch (give or take) of extra space to add in the easement; so moral of the story is you don't necessarly have to choose between 18 and 24 inch curves. If you can fit a 24 inch curve in to your space, it's not that much more space needed to add in the easement, unless you are in a very tight spot.
Whether or not a highway has spiral transitions or not varies from one state department of transportation to the next. Almost all interstate highways would use spiral transitions. For secondary roads some states use spiral transitions, some use constant radius, and some use compound curves (consecutive curves in the same direction with different radius).
For railroads, AREA recommends spiral transitions for all mainline tracks between tangent and curves and between compound curves. The only constant radius on a modern railroad would be on industrial trackage.
Many years ago in my civil engineering coursework I had to layout all those curves by hand. Today our AutoCAD and/or InRoads software programs automate the process. Makes you really appreciate the talent of the old time railway engineers.
Ray
Colorado Ray Makes you really appreciate the talent of the old time railway engineers.
Makes you really appreciate the talent of the old time railway engineers.
And current modelers ... even if I used a tool to design the easments, I don't have a GPS guided follow the dot machine to lay track. Oh ... but I do have a template made from 1/2" plywood.
Never mind, back to appreciating the talent of old time engineers.
I used to think 30" was pretty broad but then I read The V&O Story about Allan McClelland's famouts V&O layout. He showed how much better his full length passenger trains looked on broad curves (48" if I remember) than on the tighter curves. For full length passenger cars I think 36" is the bare minimum for good appearance and even that is less than ideal. Unfortunately few of us have the space for the broad curves so we make compromises. I have 36" minimum radius on my mainline and have 3 corner curves. One goes through a tunnel, one a deep cut and the other behind structures so it hides what is somewhat unrealistic appearance wise.
jecorbett I used to think 30" was pretty broad but then I read The V&O Story about Allan McClelland's famouts V&O layout. He showed how much better his full length passenger trains looked on broad curves (48" if I remember) than on the tighter curves. For full length passenger cars I think 36" is the bare minimum for good appearance and even that is less than ideal. Unfortunately few of us have the space for the broad curves so we make compromises. I have 36" minimum radius on my mainline and have 3 corner curves. One goes through a tunnel, one a deep cut and the other behind structures so it hides what is somewhat unrealistic appearance wise.
Yep, and because John Allen was not pleased with the appearance of long cars on the 30" curves, he even went as far as to "kib bash" a Walthers 89' Auto Rack car to shorten it a full panel, to improve it's appearance on those curves.
I had a 36" curve on a former layout and I know those curves looked sharp under my Walthers 89' autoracks. It would probably take curves well in excess of 40 inches to improve the appearance significantly. But most of us don't have an air craft hanger or other large space and have to cope with what we have.