I’m wanting to build a layout in my basement, i have about 6.5’ x 13’ give or take a few inches. I want to run big steam engines and passenger cars so my question is, Most steam engines in HO scale have a required minimum radius of 22 inches. Will that be an ok radius to use for running the locomotives? How bad of a overhang would the larger steam engines have? The Bigboy, Chalenger, and other articulated engines and non articulated engines like the southern pacific GS4 daylight are a few i want to run.
Sandeky–
This comes up frequently–newer large HO steamers and minimum radii. Even though Mfr’s state that the locos will take 22-24" radii, an articulated or a long-wheel based non-articulated such as a 2-10-2, 2-10-4, 4-8-2 or 4-8-4 is going to look and RUN a lot better on a radius OVER 24". Most new plastic articulateds are ‘double-jointed’, that is both sets of drivers swiveling (on the prototype, or a brass model articulated, only the front set of drivers swing), allowing them to be run on smaller radii, but then you have the ‘overhang’ problem between cab and tender, sometimes derailing the tender on a tight curve. And on locos with either a 4-wheel lead or trailing truck, a tight radius can and often will derail them unless your trackwork is absolutely perfect.
My advice is–nothing under a 24" radius, and even then you might come into problems. My own Yuba River Sub has a minimum 34" radius, and I run a LOT of articulateds on it, all except two of them are brass. And even there, I run into a non-prototypical ‘overhang’ with the brass boilers. So if you’re planning Big Steam, you’d be safer planning for fairly generous radii on your layout. Definitely NOTHING under 24".
Just my thoughts.
Tom [:)]
Define “OK”.
Will they operate on that radius? Yes. Could there be problems tracking if there are imperfections in the track? Yes. That is the minimum radius, the bottom end of performance.
Will they look good on that radius? That’s a personal judgement. I would say no. Personally i think for full size cars and those big engines you want 30" radius or better. That size engine looks great on 48" radius curves.
Since you are running minimum radius they will have the maximum overhang. Once again, how bad that looks is a personal thing. If you think it looks OK, then you will be happy. If you don’t like a lot of overhang then you won’t be happy.
I would buy a pack of 22" radius sectional track and put one of the engines on it to see what it looks like.
Dave H.
Sandeky1989: 22" is a minimum for those larger steamers, as well as passenger cars which are very long. I assume you are talking about HO scale?
If you have some track bought already, layout the track on the floor for various radii, and run a locomotive and a passenger car around the loop to see how it runs and how “you” like it. Some modelers run locos on 18" radius and are happy with the results, other modelers say no way, so it is your RR, you check things out to see what “you” like about the overhang. The rule of thumb that most modelers will tell you is to use the largest radius that your layout can fit. That way, you can use the greatest variety of locomotives and long cars and they will run and look OK.
If you had a 4’ X 8’ sheet of plywood for a bench top, and laid down track in loop at both ends, the largest radius that you have would be 22". That would mean you have a 44" diameter. As the plywood is 48" wide, this would give you only 2" to spare on either end, but some of that is the other half of the track width because the radius is CENTER LINE of the track to CENTER LINE. The long cars will overhang and look very un-scale.
Check it out first to see what you can live with.
“Looking OK” is dependant on the user. You will hear alot of different opinions to what will look good, but I will lay down the down-side to having large steamers on small radius.
-
MFGs say that a steamer will ‘negotiate 22" radius curves’. This doesnot meant that it will stay coupled to anything on said curve. The problem is overhang and physics. With overhang comes a laterial force that will be excerted on whatever is coupled to the locomotive.
-
Smaller radaii=compromises in the locomotive. Real Big Boys, Challengers and the like have an articulating FRONT set of drivers, the rear set is always rigid (sold to the frame). The models of these locomotives have both sets of drivers articulated. The problem with this is you loose detail that will be in the way when the locomotive moves through tight curves.
David B
I run a tiny SW8 and all the way up to large articulate steamers. I knew I’d have to pay attention to the clearances near steep embankments with the larger steamers’ cab in the way of overhang because much of my main is on curves…large, sweeping curves in the 40-plus inche range. A few tighter arcs are here and there, and this is where I knew to have my minimums clearly established. Then, I got the Allegheny from Rivarossi. I had lots more paring back of the ground goop “rocks” and gravel for two reasons. One was the greater overhang from the cab roof, but the surprise I hadn’t known about was the engineer’s side injector overflow. It sticks waaay out, and I had to carve a special channel in some places so that it wouldn’t click and audibly scrape in the tighter corners. So, you may find yourself having to do some carving for the sake of clearances.
As for the overhanging and binding of longer passenger cars, it will be quite a problem even at 24" radii. It will work, but expect some derailments or uncoupling…or both. As the other gentlemen have said, it is far better to squeeze out as many radius inches as you can where you want to run longer items, whether powered or towed. They will certainly work much better at 28’ over 24", but they won’t look appreciably better. You’ll need to jump all the way up to 34-36" before you notice how much better they all look. This is something I have learned by observing…you need at least an 8-10" extension in radii before you “see” that the look has improved enough to warrant the consideration and effort.
My [2c]
I would do that but i dont have anything yet. Im not going to spend a penny untill i know if i can work in HO scale like i want or if i will need to go to N scale. I dont really want to go to N scale as there isint as meny Large Steam engines avaliable to me and evan less that are DCC ready. I have 6.5’ of width avaliable to me and i want to make a moduler around the room layout with a engine servacing facility with a 130’ turntable and roundhouse.
I’m going to look at another part of the equation - your desire for full-length passenger cars.
Since HO scale 85 foot passenger cars are a foot long (close enough for the purpose - too close if corners touch on curves) you are proposing a curve that is less than two car lengths in radius. Back in the middle of the last century it was determined that a radius of less than 2.5 car lengths would cause severe problems with overhang (to the inside, with passenger cars) and tracking. That is why the NMRA specifies broad curves, and defines an HO broad curve as 32 inch radius.
Yes, you can chivvy long cars around really tight curves - but they are going to look seriously ugly when you do it.
Have you considered N scale? Or are you committed to using rolling stock you acquired before you had a place to build a layout? (If the latter, I resemble that, but I was fortunate enough to pick a prototype with shorter cars and then ended up with a larger space.)
Chuck (modeling Central Japan in September, 1964)
Slightly [#offtopic] but a few months ago there was a layout article in MR where there were 15" radius curves on the track plan and in the story the trains were pulled by 2-10-0’s. That made no sense to me. Big locos need lots of room. That’s one more reason that I won’t be getting a Big Boy or Challenger for my birthday. Sure they’ll run on my 28" curves. It’s the hidden, hard to get to staging yard turnouts that concern me.
The Onion Specific designed the Big Boy to operate on 20º curves; if you want to do the math that will render out to a 39.5 inch radius curve in HO-Scale. The NMRA Recommended Practice for 85 foot HO-Scale passenger cars would be just a shade greater than 35 inches.
I have been in a couple of clubs where curves were of that radii or greater but most of us do not have the luxury of a layout space allowing for those broad curves. We consequently must compromise; you could, for example, easily lay a 30" radius curve on your 6.5 foot dimension.
It also depends on what you’re willing to put up with. My 2-10-2 can take 18" radius all day long but it looks a bit strange doing it.
I HAVE an Athearn Challenger, and have a double loop on a 4x8, which means approx 22" & 18" radius, and the Challenger will run on either loop. That all said, IT LOOKS PRETTY SILLY ON THESE TURNS!!! The grandson loves it, but it only runs when he is here!! Next year I’ll be in a new house, and the minimum radius will be 30" except for the yards, and 36" or better where possible. To give you an idea of overhang, a double track tunnel portal is required for the Challenger on single track!And that is just barely enough!! You should have enough room for 24"+ curves, but if your track plan does not allow them, go to N gauge (make sure your eyesight is better than mine!!) My [2c]
after running some more measurments i think i should be able to use 28+ inch radius curves on the layout. The main wall i have to work agenced gives me aproxamently 7ft 4inch of width and anyware between 12 to 18 feet long (depending if i can build up agenced the furnace on one side or not, I dont even know where to look for that info).
Just my 2 cents…
I run all “small steam”. My largest is a 2-8-0 Bachmann Spectrum Connie. I think it looks good on my 18" radius. But a larger engine should go on at least a 22" radius.
No offense intended, but that post hurt my eyes.[xx(]
Against the furnace? Ahhh…shortest answer possible…NO!
A couple of things. Will your household insurance, and will local fire safety ordinances/codes allow you to build so close to a heating appliance of that kind? Better check it out. Secondly, if the answer is yes, you could build it so that the closest 3’ flip up on hinges and rest on extendable supports sliding in the frame below the hinged flat part. All you need is occasional access to the furnace, and all it needs is space around it for proper combustion. If the bench top is above any louvers, and you can flip part of it up and out of the way for maintenance, I don’t see the problem.
Better check safety regs, though.
Depending on your furnace, 6" MINIMUM!!! If you have a newer furnace, where the “skin” temp is never hotter than you can put your hand on, then 6". If an older unit that gets “hot” to the touch, 12"+!! You should really check your local building code, if not & you have a problem, homeowners insurance will not pay for any resulting damages!! Regardless of spaceing, you should have and section near the furnace removeable for any future maintenance or repairs. You wouldn’t believe, that as a remodeler, how many “finished” basement walls I had to remove so that the furnace or hot water heater could be serviced/replaced!![:O]
I wasint talking about building right up agenced the furnace. at the moment i have left 2 to 3 feet of space away from the furnace on the sides im building on. its a farly new furnace and it never gets hot(evan in winter when its 20 degrees outside and its on most of the day and night).
MOST equipment built today will 'stay-on-the-track @ 22" r, even if they have to fudge wheel size. it’s called ‘ROI’ or ‘$ale$’. Beginners create a ‘lopsided’ market.
MOST CLUBS built their layouts with 36"r curves for their members’ brass steam.
I personally think it takes 48"r to make 85’ passenger cars and artic’s look normal. My Westside AM-2 4-6-6-2 wouldn’t take my Atlas 26"r curve, so I replaced both.
Your 6.5’ X13’ dimension will accomodate a 36" radius loop. I suggest you use it.
AGAINST! Please! My eyes!