I like my 18" curves and I can run some pretty big locos on my layout, bigger than some people would think. The thing that makes me sick is the people who think 18" radius = tiny 4 wheeled diesels and equally tiny rolling stock. It doesn’t you know. I run a pair of enormous SDP40F’s at the head of a 22 car freight consisting of some 40’ cars but mostly 50 and 60 foot cars. It might not look good to some but I can watch it run all day long and enjoy it. The SDP’s have the outside track with a 30+ foot run and a pair of GP38-2’s pulling 14 cars have the inside track with a run of around 20 feet while a team of SW’s handle switching chores between spurs on both main tracks. Now that makes for a tight operating schedule. Add to that the mains are running in oppisite directions.
Ok. There are two viewpoints here that need to be examined. The I can run a Big Boy (or something else big) on 18" curves and am happy doing it viewpoint. The other is a group who are trying to railroad in an as close to prototypical arena as we can. Well the arguement is even real railroads would only go around a 30" radius curve at a top speed of 5 mph. True but the amount of compromise is what is in question not the ability to do it. We could start a, “I can make my six wheel diesels go around 15” curves. All I had to do was cut off the steps" debate to be followed by I can get mine around 13" curves. Rediculous? You bet and not meant to gore anyones sacred cow. A properly done urban switching line in a small place with tight curves and clearances can be a real gem. Modeling a class one with super power, 85’ passenger cars and a four track mainline is not appropriate in my opinion.
Call me silly, but I think 4 wheel truck diesels look awful on 18" curves as well. YMMV.
You certainly can run a model RR with 18" R curves - take a look at the current MR project layout !! But you have to be prepared to limit what you use to shorter equipment…although that can be deceiving too, an 80’ passenger car with talgo trucks (trucks with attached couplers) might do better on an 18" radius curve than a 60’ Walthers passenger car with body mounted couplers.
I know the Life-Like RDC will do 22" radius curves, not sure about 18"?? I suspect it will, probably have pretty good amount of overhang though. As someone mentioned, you could try to hide the curves with scenery.
Keep in mind you don’t have to have continuous running to have a model railroad, my layout is currently a 12’ by 12’ L-shaped switching layout built along the walls on 16" wide shelving. I use No.6 turnouts and 31" min radius curves.
Well On30 stuff from Bachmann will do 18" radius curves I believe, but remember HO is “Half O” scale so that’s a pretty sharp curve in O scale. I know some On3 steam engines are recommended for 36" radius curves for example. (18" = 130.6 HO feet; 18" = only 72 O scale feet.)
And my point is just because you’re hampered by tight space and a switching layout or N Scale are out of the question, you do what you can. All I have space for is 18" radius but I’m not going to let that stop me from running things bigger than small geeps and 40’ cars. If I was to go with 30" radius all I would have is a very boring single track oval. With 24" radius I would have two boring ovals with no chance of a passing siding (been there and tried that). With 18" I have the inside oval with a crossover to the passing siding of the outside track which runs an ‘L’ shaped course. The inside track has a branch with 2 spurs and the outside track has 5 spurs. How tight is my space? Expanding to even 20" radius and keeping the ‘L’ shaped run with it’s passing siding and crossover to the inside track wouldn’t be possible. So I was faced with a choice. Go with 22" radius and have 2 ovals with 1 or 2 spurs from the inside track and 1, maybe 2 short spurs from the outside track and possibly a crossover between the 2 mains or go with what I have which believe it or not still has a little space left for another spur should I choose to add it later. Big sweeping curves are great IF you have the space. I don’t, so I make do with what space I have. This is the same choice the OP has. I try to show fellow modelers what can be done with a small space without being limited to small power and small cars. In the end it all boils down to what you’re prepared to live with.
The only thing I would add to this discussion is that before you make your final decision you probably want to go into the MR General Discussion board and read through the thread entitled: Ever Build A Layout That You Thought You Wanted But…
The point of that thread being that whatever compromises you make today, you are going to have to be willing to live with for the life of the layout.
The point of a hobby is to relax and have fun. Do what suites your needs. If that means running modern equipment around 18" radius curves, the only limit should be will it go around them without derailing or wiping out something adjacent. Purists might say18" radius is only appropriate on a trolley line, and doesn’t fit with regular railroading. Let them do their thing, you do yours.
In high school, (early 60s) after reading a discussion of this nature, I took an oportunity to measure the overhang on a 40’ box spotted on a curved siding entering a local lumber yard. I forget the actual measurement, but when I used an HO 40’ box car on an 18" snap-track segment, and an HO scale rule, I measured significantly less overhang. And before the lumberyard closed, they were taking deliveries on this same spur from 60’ boxes. How unprototypical, B&O/CSX.
If we were fordidden to build our layouts using anything but true to scale radiuses and spaces, no selective compression, small radius curves, # 4 or 5 (or maybe anything less than #8?) switches, we would have what, maybe 20 model railrods world wide, with only that many people in the Bill Gates income level with enough room to model anything other than a small short line or one small local industry? Who could do a true scale model just of the former B&O yard in my home town? In HO, it would require a table about 8’ wide by 270 feet long (4.5 actual miles by about 60 actual feet in an HO scale mile.). And that’s without a side extension for the old engine terminal that had about a 14 stall roundhouse and a turntable big enough to turn an EM-1 Yellowstone, and a very long enclosed elevated coaling bridge.
Do what fits your situation, and have fun doing it. And for the critics, Corborundum non iligitimi est! (Loose translation, don’t let the (Beeps) wear you down!)
I think most manufacturers make their equipment to run on 18 inch radius curves, even the bigger stuff.
You can maybe plan the curves to not be totally visible. Concealing even a portion a sharp curve in a small tunnel, a deep cut, or under an automobile bridge can hide the sharpness.
Also, if you are using sectional track for instance, you could blend the overall radius by mixing track of varying radii. You could have the apex of your curve one section of 15 inch radius, if your stock can handle the sharpness on that one section, then use 18 and/or 22 inch radius as you fan out towards the straight track. Conceal the apex and the visible part would actually be greater than 18 inch radius.
18" should be fine, but make an easement on the way into the curve. Also, make sure your trackwork is perfect+ on the curves. Any little nick will derail a train with long cars. Also, watch out if you have long passenger cars. They will derail a lot on those curves, especially with nasty trackwork.
MadSinger
That a matter of priorities. If realism is a primary concern, they you wouldn’t. If running whatever trains you want is, then you would.
You can do a lot of things int this hobby that physically work, but aren’t realistically representative of the prototype.