Which radius for big boy is best?

When it comes to the Big Boys, the bigger the radius, the better.

Go with the biggest radius you can get away with.  It will also make the larger scale rolling stock and passenger equipment look better as well.  In fact, all trains look better on bigger curves.

Andy

As Andy said, "Go with the biggest radius you can get away with".

I have Ø108" and Ø99" outer and inner curves on my dual mainline, and have practically no issues with interference with other rolling stock and the Big Boy (new Lionel VL and MTH Premier). The overhang looks a bit funny, but not too bad. I have yet to hear a visitor, whether model railroader, say anything about the overhang; I guess it is sort of expected.

Having said that, here is information on the 1:1 Big Boy. (Excerpt follows.)

"What is the Sharpest Curve a Big Boy can Negotiate?

The sharpest curve the Big Boys could negotiate was a 20 degree curve. In HO scale, this would be a 40 inch radius curve."

That would be (40x2x87/48 =) Ø145" curves in O-Gauge.

Good luck and let us know what you end up doing.

Alex

I have 0138, 0128, and 0120 curves on the far end of my layout. The layout is 14' wide and I think these curves look great.

Gargraves 113, 120, 128 and 138 all use four sections per 90 degree turn. IMHO, it's going into the curve that the boiler overhang is most noticeable. Putting the largest curved section first helps that to some degree. 

You can mix your curves to squeeze things up a bit. They all mix and match and you still end up with a 90 degree turn. You could (for example) go: 138-113-113-138 if you wanted to.

While the geometry is a tad different, I use both 089-080-089 and 080-072-080 combinations on my layout. If I didn't specifically point it out, you'd never know. But to my eye, these curve sections just look "better". They're not just a plain symmetrical "quarter circle" shape.

Gilly

As I see it, railroads had existing laid track. As locomotives got larger and longer, negotiating the curvature of the track became a limiting factor. 

Faced with the choice of relaying all their track to accommodate longer locomotives or designing longer locomotives to negotiate the existing track, the design of articulating locomotives became a reasonable, economical option. (though the Garratt is a better design option).

So, IMO, why relay your railroad?

Disclaimer: O72 is a very large degree of curvature for a realistic appearance.

good advise from andy. like alex, i have 099 and 108 curves, and bb looks pretty respectable on these .there are so many of the magazine layouts that waste the space they have in favor of secenery,instead of using the largest radius/diameter curves.i will do anything to improve operation reliabilty.-jim 

Articulated locomotives have "overhang", where Garratts have "underhang". The turning center of gravity of the Garratt is better suited for curves.

Minimum diameter is similar maximum degree of curvature

Eric Siegel, in his fantastic review of the Lionel Vision Line Big Boy, recommends a minimum curve of O72.  My LionMaster Big Boy, which I found out is double articulated, believe it or not can run on an O31 curve.  I really don't want to see that.  My tunnels on a O45 curve have to be double-width to accommodate the overhang, but alas I just don't have the room for wider curves.  Therefore on my layout, the widest curve can only be O54.

Bigger is better.  Huge is best.

.....

Dennis

Ditto on bigger is better.

As Gilly mentioned, mixing the radii in curves (largest first and last) is cosmetically more attractive than the usual 1/4 curve regardless of diameter. 

You can save some $$$ by using Gargraves flex track with individual pieces of GG sectional track in several radii used as a template.  Just flip the sectional track upside down to check your radii as you lay the track.

Another thought is to use an exceptionally large radius curve for what John Armstrong referred to as a "cosmetic curve."  It would be a curve that is much too large to use elsewhere on the layout, but would provide a dramatic viewing perspective of your engines and rolling stock.

It would look pretty sweet on 200.

It's not really that bad.  The K-Line Big Boy is the same and I've run mine on O27 curves.  And it's not the boiler you have to watch out for, its the back of the cab that has the worst overhang.

But for scale Big Boys, it's really what you are comfortable with.  I run my VL BB on O72 curves, and I am fine with it.  It's also the biggest I can do.  If I had more room, yes, I'd go bigger, but since I don't I am happy with running at the min.

I run 0144 and IMO my BBs look nasty.   Almost like an awkward yard movement.  I could not imagine them on 072.

If you do a search, you'll find lots of threads on this subject.

In the meantime, here's one of my BBs on 0-138:

So, what you are really saying is that SIZE does matter.  LOL

Rick

Short answer- as large as you can fit.

Bending flex track with a 56.5 radius in 30° sections will take a 10' wide area by 5' long with ~2" clearance to edges for a semi-circle.

BigBoy will look good on that.

Beware of distorting your layout just to run the largest locos more beautifully.

There  is always a price to pay in design .

I know, I did it.

What will help visually is:

• Around-the-walls construction. This puts you on the INSIDE of the curve so you don't really see the overhang. Also, you can't see the entire layout which improves the perception of the length of the route and improves the perception of scenery depth.
• Near-eye-level track elevation. This keeps you from looking down on the overhang.

This post is perfect as I'm bidding on a MTH challenger 4-6-6-4 and I just saw some one selling one identical and I saw how much the engine actually hangs over past the track as it goes around a corner and I'm saying to my self rut rho as my O-72 track goes almost to the edge and two area would be putting the engine of possible of hitting a brick wall or at least scraping so I may have to look into readjusting that track back a few inches at each end. and while I'm at it may look into get some Gargaves O-89 ( 8' wide layout) to give me a better swing and not hang out as much can't go any wider as it buts up to the door as it is. so need to see when it gets here will will need to lift second level to be sure on that corner. 

Well thanks for the topic as it got me thinking especially after seeing the one for sale the guy had. He had a short video showing how it swung out 

I have the VL Big Boy and it handles 072 ok but I an adding an 084 elevated loop just for the VL BB, only regret is I did not use larger than 084, layout could have handled the next size (fastrack)

Brent

I have the VL Big Boy and am running it on its min of O72 small living room layout - yep a lot of overhang; I think another thread indicated that you need at least 5in from the center rail to the wall.  Anyway, in my final layout, I will use at least an O84 or as large as I can get to make taking the curves as smooth as possible.

i am running it on it on o72 but it wants more!!!!

if i do more that 72, am i take away the effect of the over hang!!!!

Yes, but the engine is designed to move that way, just not as much as the models do.

Scrapiron's comment really caught my attention. That's coming from someone with(had) a very nice layout.

If you like your layout and the BB is clearing everything, why change it? Don't change it just for the BB.

Going from 0-72 to 0-84/0-89 or O-96 is more effort than it's worth.  You will not see much of a difference in boiler over hang. 

If you ask one person, O-72 is the best, if you ask someone else, 0-160 is best.  Only the OP will know what he prefers.

IF space isn't an issue, I'd start at 70" Radius (0-140) and preferably larger.  I'll see if I have pictures of mine on different radius, not sure I took other photos.

AGHRMATT posted pictures a year ago with a BB passing scale passenger cars in a curve.  Maybe he'll post them again for you.  Or, do a search.  It's here somewhere.

Enjoy your locomotive. 

Ha!! Viva la over hang!!

When friends get a load of the overhang, they are mesmerized - shuts'em up for a minute.  lol

BUT, with a wider diameter, would there be less binding on the wheels and less stress on the drive train??

Seems like some of the modellers here have a lot of layout space and some do not. I am unfortunate not to have any space but I am addicted like many to this hobby. i may be able to barely manage 072 for my BB.

So, if you have the room, go as big as you can. If you don't have the space but can go with 072, then go for it....Why waste so much space for 080 0r 096 when it makes minimum ovehang difference vs 072?

I run mine on 096 curves and it looks ok,I did my three main lines in 1999,if doing it today I would go with 108.

Mikey

There's no such thing as wasted space..... it's called scenery

What Lionel needs to do is chop some of those articulateds in half and make some real nice 2-6-2 Prairies for those of use stuck in the 4x8 world.

AGHRMatt and Elliot give great advice. There is always a delicate balance between super large curves on a layout and the overall design of a track plan.

It really comes down to what is important to you, but it is worth remembering that a very large curve must be used to get the overhang down to a semi realistic level.

Jeff C

The real issue with the creation of a layout specifically done for the giant locomotives is that it radically rearranges what the primary purpose of the layout is. We all know that unless your layout is more than six or seven hundred square feet you will not be able to build the radii for a Big Boy to look good (O-90 or greater) and also do anything other than run your trains in some type of giant loop, be it a figure eight or something similar. That giant loop changes scenery plans, the operation of the trains, and creates what is essentially, an around and around scheme that becomes a bit tiresome.

I know that some will say it is worth it to run the Vision Line Big Boy in such a manner, but the Big Boy is just one locomotive. After you have run a thirty or forty foot train around the layout a couple of hundred times you begin to realize that such a plan makes it much more difficult to have really interesting variations of level, scenery, and operation.

I designed the Munoz Lines to accommodate the largest locomotives. Even so, the Big Boys help me redesign mountainsides and cliffs their own way. After some of the initial runs, I found rocks, boulders, and even mountainsides on the right of way. It was worth it for a while to run these giants. Eventually, however, I found that giant locos and long trains grew a bit tiresome. I wanted more operation and action. I put the big articulateds away and started running smaller trains and they looked so good on the radii I had, (minimum of O-72 up to O-90) that I continued with them. The articulateds looked great as shelf queens.

The key, and Frank Mullen would undoubtedly agree, is to know exactly what type of layout and operation you want. If giant locos and long trains are the explicit goal, then you better have O-90 or greater because the Big Boy will rearrange your plans and will not look very good with giant overhang at O-72. I had O-72 minimums everywhere and did a lot of telephone pole replacement.

My greatest joys became the creation of scenery and, guess what, the Munoz Lines is now gone. I found that endlessly running giant locos around was not as much fun, nor as creative, as I wanted it to be. That is me, of course, and others may be much different.

My advice, identify what you love and follow that. Just understand that once you make those large radii decisions, the operation of your layout will follow suit. If you love wonderful scenes, locos pulling in to stations with passenger trains, sidings where interesting things happen, you can STILL have those with the giant radii, but it will change all of those pieces and not necessarily result in more enjoyment.

In any case, have fun and have fun your way. The Munoz Lines is now gone. I really miss running the trains but I know the next layout, smaller and with great character is where I would like to go.

  The orignal train room is 34x16 and I just took a wall out that was a closet. That is the area I metion earlier in the post. I have a few passanger set that need more radius too. I have been trying to avoid a duck under.