Minimum Curve Radius for 6 axle loco

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#1
Hi.

What is the minimum (or suggested minimum) radius for a 6 axle locomotive.(HO)
I have two areas that have 22" curves, and I'm sure these are fine.
I am more concerned with the majority of my curves which are 18"

Thanks-
 

bnsf971

AKA Gomez Addams
Staff member
#2
22" is usually minimum radius for smaller 6 axle locomotives. "smaller" would be SD7-SD35, or RSD4/5 and RSD12. GE has never made a "small" domestic 6 axle locomotive, and all are longer than an SD45.
 

jeffrey-wimberly

Dr Frankendiesel
#3
I've run Athearn locos as big as SD40-2's and SDP40F's and SD45's on 18" radius as well as Proto 2000 E units and several large Atlas 6 axle locos. SD24, U30C and H24-66 Trainmaster.
 
#4
I've run Athearn PA and PB's on 18-inch radius track, and SD-7's as well. The Alco's sometimes gave me trouble on #4 turnouts. I solved this by removing the wheels from the center axles on each truck. The gears on the center axle were left in place in the gear train. You can't really see the missing wheels unless you get right down at track level with a light behind the truck.
 
#5
Hi.

What is the minimum (or suggested minimum) radius for a 6 axle locomotive.(HO)
I have two areas that have 22" curves, and I'm sure these are fine.
I am more concerned with the majority of my curves which are 18"

Thanks-
most 6 axle units will go around 18-22" rad. curve. However, the cars behind them may not. I have one industrial track with 20" rad. curve my 6 axle SD's go through fine. But the 50' hydracushion car behind it derails. Thus, only 4 axle units are allowed. Phil
 
T

tmiller

Guest
#6
I too have the same problem with the loco doing fine on an 18" radius, but the first car behind gets pushed off negotiating a turnout. Is there any correction for this problem in regards to the couplers, or is it all dictated by the trucks not moving enough?
 
#7
Long shank couplers can help. I use them on my permanent lashup of two SDP40F's and the first car behind the locos. If you're pushing/pulling cars through a turnout that makes an 'S' curve there's little that can be done short of putting a straight piece of track in to eliminate the 'S' curve.
 
#8
My long wheel base Walther's 60' cars have long shank wide swing couplers and don't seem to have a problem. But the 50' cars with the cushioned draft gear say nO way. The couplers are limited as to how much they will swing to the inside of the curve and then something has to give. Derailment. Phil
 
#9
All of my childhood our Christmas layout was comprised of a bunch of 18" curves and we had one conrail sd-40 by lifelike that took those curves great. I don't currently have any 6 axle diesels but I have seen other people run 6 axles on 18" w/out problems. I think that it will depend not only on the type of loco but also the individual loco as well. I have had 6 axles give me no problems but have had 4 axles give me hell on the same turns. It's just one of those things sometimes it works sometimes not. Sorry wish I had some better advice for you though!!!
 
#10
I run an Athearn Genesis SD70ACe on 18in curves with no problems. Ive also run a DD40 (8 axles) through the same track.

I believe, and i cant garuntee this, but i believe most manufactuers make their locomotives able to run on 18in curves because they appeal to the largest group of modelers. They may not look great, but they dont look terrible either...
 
#11
for the beginners

is there a spread sheet that gives some kind of guidance for the different engine nominclature number of driving wheels/etc and track radius it safley runs on . too much info ?
mike
 

UPBigBoy

J&A Paint Shops
#12
We've had 6 axle trucks give problems in the past; whet we did was remove the flange from the centre axle, that way the truck would act as a 2 axle truck which eliminated the problem. another way to over come this would be to use a truck mounted coupler on the first car behind the loco.
 



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