EDIT: Do 6 axle locos handle 18" curves?Snap switches?

About a SD45 down can handle an 18 inch curve from my experience. But they don't look nice. SD50 ups might be able to handle an 18 inch curve, but they would not look nice at all. My recommendations would be to stick it with the Geeps.

SD7s and 9s should be alright. All else fails, get guests and tell them that these locos will never run right on the turns. Nearly Guarenteed way to get them to work right. Engines love to make liars out of us.

galaxy,

As WC mentioned, 6-axles can handle R18" curves.  They just won't look pretty doing it.

The one thing that you may have problems with is negotiating any contrary or "S" curves.  You'll need a straight section of track between the contrary curves as long as the length of your locomotive.  Otherwise, the front and rear trucks on your locomotive will be pointing the same direction and it will derail.  This happens because the rear truck is coming out of the curve as the front truck is entering the curve.

Hope that helps...

Tom

tstage wrote:

galaxy, As WC mentioned, 6-axles can handle R18" curves.  They just won't look pretty doing it. The one thing that you may have problems with is negotiating any contrary or "S" curves.  You'll need a straight section of track between the contrary curves as long as the length of your locomotive.  Otherwise, the front and rear trucks on your locomotive will be pointing the same direction and it will derail.  This happens because the rear truck is coming out of the curve as the front truck is entering the curve. Hope that helps... Tom

TX Tom, I have no "s" curves EXCEPT maybe at the snap switches. Do you have any idea how they handle snap switches?

jeffrey-wimberly wrote:

I too have all 18" radius curves on my layout. I've run Athearn SD40-2's without a problem and even a RTR Athearn AC4400 after a slight modification to the coupler pockets. Add to that the number of other six axle locos I run, P2K E6's, E7's, PA's. Athearn PA's and PB's.

THANKS JEFFREY!

My original post title mentioned SD's, but the body of my question said I avoided "6 axle locos like the plague".....my faux pas! (I EDITED). I wondered about all 6 axle locos, really. And I wondered about E series too...saw one at a hobby shop the other day that was soooooooo sweet and swell, but I thought "I can't run that"...so hence, this question!

galaxy wrote:

Hi all, Do to space limitations, I have 18" HO curves, and have to use Atlas snap switches. I have avoided 6 axle locos like the plague. DO they do well on 18" curves? Can I run them? How do they do on snap switches? TIAFAYH

I had spent ten years building HO-Scale steam lokes but when I finally found it possible to build a home layout I too was restricted to 18" radius curves. Do what I did: convert to N-Scale where 18" radius curves are considered broad curves.

R. T. POTEET wrote:

I had spent ten years building HO-Scale steam lokes but when I finally found it possible to build a home layout I too was restricted to 18" radius curves. Do what I did: convert to N-Scale where 18" radius curves are considered broad curves.

I have N from my teen years. When I got back into the hobby 2 years ago, I started with my old N scale stuff,and even added some new. The thing is, I always always always wanted HO, so I went for it!

I am content with my small HO layout, until I have a bigger space. I know I could have quite the N layout if I wanted it, or went back to it

As for now, a small N scale layout gets run at christmas!

I have 18" curves on my old layout, and have no problems running the 6 axle locos I have on the layout.My P2K E-6's, SD45's, even my DD40AX all handle the 18's, but may look kind of funny doing so. Even my 2-8-8-2 traverses the layout just fine.

But, I did spend a LOT of time on my trackwork, making sure it was as perfect as I could make it.

Rotor

RAILROADS AVOID running big 12 wheel 'Road Diesels' on their tighter curves. Tight curves mean slooow speed restrictions, and almost every curve has a speed restriction. RR'S are concerned with delivering goods safely. Derailments cost money.

Modelers don't have these restrictions. Makers cheat on out-of-sight underbody detail and wheel size to navigate 'play' curves on plywood sized layouts, because it's profitable, and newbies aren't generally that fussy.

Derailments are an inconvenience requiring only 5 fingers, and all cars are empty. It's fascinating what some modelers consider 'acceptable', or 'excellent.

Actually, it depens on whose engine can navigate whose curve. Brands are different.

Expensive Brass is more like the Prototype and fussy'er while the cheaper products have fewer restrictions.  I find my brass 4-8-4s barely squeeze through switches that the same 4-8-4  plastic 'sails' through. Come to fnd out the plastic model has incorrect, (and smaller wheels). Ah, progress!

I long ago switched from Snap switches with 18" r. to #4's, and now select my fussiest 12 wheeled engine to determine what works on my #4s. Better yet, I bought a switcher to do my switching, and a mainline SD-45 for hauling. Never do they invade each others territory.

I now operate like the Railroads, but it's taken awhile.

My Passenger engines pull only passenger cars. My GP's pull short freights, and my SD's long. My 'Work Train' sits on a siding. I bought a brass 2-6-6-2 AM-2 that wouldn't make my #6, so I sold it. I had already tested different #6's and 8's take up too much room.

Everyone has some limitations.

WCfan wrote:

SD60 on an 18 inch radius. It can navigate the 18 inch radius, but some times the front truck wheel will derail. (Sorry for semi blurriness. It was a quick pic, but you get the idea) GP40 on an 18 inch radius. This can handle the curve well, but still has a bit of overhang. My SD45s can handle the curves, but sometimes (But not often) the front truck wheel will derail...deepening on track work this might not be a problem, my track work is horrible...

Thanks for the pics and info!!

Q: Do 6 axle locos handle 18" curves?Snap switches?

A: Some do, some don't - but none do it well. Depends on what you mean by "handle"- Stay on the track?

A '4 wheeler' looks about right. NMRA recommends 40'-50' cars. GEOMETRY: is straight wheel alignment on a curved oval. How much 'slop' can you get away with?  Mfgrs. call it "play".

'Shorter' is better. A full length passenger car is approx. 12" long. Lay a ruler on your 18"r. sometime. See the problem?

Some smaller 6-axle engines can handle 18" curves.  Mostly older prototypes, like SD7-9s and ALCo RSD4-5, RSC-3.  The ALCos are 3-axle trucks slung under a RS-2 or 3.  SD7-9 are about the same length as a GP38-40.  I haven't used snap switches, they might give problems.  A #4 does give sort of an easement into a 18-22" radius curve. 

Track gauge through a curve is a bit wider.  In 1:1 scale, not uncommon to add an inch in sharp curves.  Depends on the size of the rigid wheelbase.  Steam engines need bigger curves, wider gauge in tight curves, and lateral motion devices to allow the drivers some flex to get around the curves.

I have run SD40-2s and AC4400 through 18" curves and #4 switches at high rates of speed.  Doesn't look good, but can be done.  If something can be done doesn't necessarily mean it should be done.  My 4-axle power looks much better on the smaller curves.  It can still be used out on the main line.  I haven't acquired 6-axle power in a while.