Ok so here is the question.
If I have a 6 truck enine, what’s the tightest radius curve/loop it can properly navigate through??
I’ve finally got my benchwork built and am messing around with track plan ideas in the space I have, will most likely use 6 truck engines on my layout, but in order to help me properly design a track plan and smooth operation of the trains, I’d like to know what the minimum radius is for 6 truck engines.
Thanks.
What scale? What make of engine?
Sorry forgot to give that info.
I haven’t bought any engines yet, but the scale is HO.
Since I don’t have any engines, what’s the average radius one would use??
“6 truck engines”? What engines are these? Normally diesel locomotives have two trucks–some electrics designed for low ground pressure had four. I assume you mean six axles.
Radius depends on what size of locomotives you want to run–typically the smallest size most people like to use is 18" radius, but 22" or better is recommended for anything larger than smaller locomotives, and the bigger the radius, the better the curve will look. 30-36" is considered a nice broad radius for big articulated locomotives or things like 85’ passenger cars or auto-racks and whatnot.
Yes, sorry again, I meant 6 axle engines. My use of terminology sux.
Thanks
I’d say 22 or 24…
Longer engines like modern 6-axles or old DL109 diesels will run better on the 24.
PA’s and smaller units like RSD’s will do fine on 22.
So with an HO scale layout, I’d need (to be on the safe side) 22" radius curves. This could throw a wrench in my design plans.
Whats the minimum recommended radius on N scale, assuming 6 axle engines?
Tim; in HO, you need 40" min radius to be on the safe side, 30" min is reasonable for most equipment.
In N scale, 18" min is desireable if you want to run modern frieght, or scale passenger of any era.
I’m just starting my track planning/design and wanted to know myself. I know excellent trackwork is crutial for smooth operation and I don’t want to end up finding out the hard way that an 18 inch radius is too tight for a six axle loco. Of course I don’t have no big club size layout and tons of space so I need to know the tighest I can safely get away with too.
A 40" min RADIUS? that would give a curve 80" across at the widest point, or almost 7" wide. I thought a 20" radius (40" diameter) curve would work for most in HO. Thats a lost more room than I have to play with.
they say 18" will work but it’s real “iffy”…I wouldn’t go below a 22" radius using six axle diesels …they will run on 18" but they have to go real slow and the chances are they will pop off the track in a curve at the slightest inperfection…if you use 4 axle diesels and 40’ cars the 18" won’t be a problem…it’s going to either be smaller locos for a tighter radius or a wider radius for the larger locmotives…i know it cramps your design but the law of MRR physics always wins out…chuck
I think he meant over all diameter. Radius would be half that from center out. I have old sectional curve pieces, made a complete circle out of them and the total diameter was 36 inches, divide that in half which is center for an 18 inch radius.
I could probably fit in 22 inch radius curves into my layout. All I have is 90 degree turns at the corners of my table, I don’t have any reverse/full loop sections.
With radius, it’s “the bigger the better” but you must constrain that by the reality of fitting your mrr into the space you have. On a “minimum” basis, even for 6-axle diesels, I find 40" quite excessive, even 30" is a bit much. If you can do 30", 40" or even more, great! go for it! But on a ‘minimum’ basis I disagree.
Most modern HO equipment is made to run on 22" radius, even big articulated steam and large diesels. Manufacturers will usually say quite clearly if it needs more than that. I’d suggest you’ll be quite safe for almost anything with 24" min. radius.
Well if your saying 30-40 inch radius then I assume the many people who only have 4x8 layouts have no more than 22 inch radius’ and only run 2 axle engines?? Surely a 2 truck 3 axle engine this day and age in MRR can easily navigate a 22 inch or even a 18 inch radius curve with no problems for those who don’t have big ol club layouts or layouts that fill their entire basement that can’t afford that kind of room.
22"-radius works well for me. There are Athearn SD40-2’s, Kato AC4400CWs, Atlas C40-8 and even an extra-long Athearn FP45 on my roster, and they all can negotiate 22"-radius curves and #6 turnouts no problems.
Yeah, 22" curves isn’t strictly prototypical but room constraints dictates that I need to use them.
Well I’d like my layout to be as prototypical as possible but I don’t have tons of space so something has to give but it has to give and still operate smoothly. If I have to use 2 axle engines to accomidate smaller radius’ to fit on my layout…so be it. i just wanted to find out what the minimum possible is for 6 axle engines. 22 inches seems to be the consensis so I’ll modify my track planning to that and see how things work out.
Thanks for all the replies and help .
What era have you decided to model, if any? Do you want to run 87’ passenger cars?
Wider is always better but not always practical.
Another thing to watch out for in your track plan is tight “s” curves. They have a way of sneaking in. If you have an “S” curve situation, be sure the tangent or straight track between them is at least as long as the longest car or locomotive you will be running.
I would LOVE to use 40" radius as my mainline minimum, but my basement isn’t big enough to get the operation I want if I use curves that big. SO I am using a 30" minimum. Testing with even full-length 85’ passenger cars shows that they will handle this with no problem, even with diaphragms. 40 and 50 foot freight cars DEFINITELY have no issues here - in my yards and on branches I’ve gone as low as 24" radius, and even most of the passenger cars can negotiate that. Certain ones have interference issues with the diaphragms on the 24" part, but they wouldn’t be run in that area anyway, it was just for testing.
And even the 30" radius is to accommodate others. The 85’ passenger cars aren’t mine. The only passenger cars correct for my line are 70’ and less - I’d probably use a 26" minimum, maybe 24", although the T-1 is definitely happier with the 30" radius track.
–Randy
No hard fast minimum - depending on the maufacturer.*
RULE OF THUMB: Steam & 6 axle Diesell.
SAFETY FIRST: 22" radius and #6 turnouts.
TIGHT SQUEEZE: 20" radii and #5 turnouts.
18" Radius: (buy 4 axle diesels and #4 turnouts).You’ll be happier.
*The more expensive the product: Bigger is better. (24"r+)
The chaper products aim more at the ‘Toy’ buyer.
This is the same problem I have.
LACK OF SPACE!
Large radius curves are great if you have the room but since I don’t, I’ll stick with 22" curves which are good enough for me.
I can run all kinds of plastic locomotives & Walthers Budd cars on these curves with no problems.
As I have stated in another post today, I started off with 18" curves but removed them for 22" curves to allow for larger equipment to be run.
Anything larger, I’d have one oval at best with very little switching.
Gordon