Do You Prefer Six or Four Axle Locomotives? is a free Model Railroad Discussion Forum and photo gallery. We cover all scales and sizes of model railroads. Whether you're a master model railroader or just getting started, you'll find something of interest here.


Well-Known Member
I like single axle locomotives. I run O scale with 2" radius curves. Superelevated, of course.
That's a pretty tight radius ! You should go no tighter than 3"- 4" r curves..Are you hip to the new almond milk powered controllers ? Never add chocolate or you'll have mucho problems..The new adjustable flange depth feature on the Rivathearn camelbacks is well worth the extra cost !!


Well-Known Member
I'm actually about to start a rebuild of part of my layout so that I CAN run more 6 axle locos. Currently I run mostly GP 4 axle units and I do have one U25c, but I started with 18"r curves, so I've been limited. Trying to ease away that limitation.


Active Member
When I had my layout the only 6 axle units I had were Athearn Trainmasters , they made the 22" radius fine and the 18" yet they have an off set center axle. I have never run the SD40-2's on a layout. I've seen all sorts of attempts done to modify the center axle , none I would care to do, most involve allowing the center axle to move higher into the truck by grinding the metal area that the square axle bearing fits deeper. That seems to be their cure for uneven track or a tight radius. Seems like many manufacturer's shorten the bolster to bolster length enough so the model will stay on the rails and make the tighter turns at least on the 6 axle units.

Iron Horseman

Well-Known Member
I like 8 axle locos. 2-8-2 for the branch lines, 4-8-4 on the mainline and a nice 2-8-4 Berkshire for fast freights.
That was my first thought - 8 axle. Almost nothing beats a 4-8-4 for looks or general performance.

I probably have more 4 axle diesels than 6, but as for preference I have none. Sets of 4 axle locos are often 3, 4, or units while six axles usually run in pairs or at most 3. Good old GP7 or a hard working SD40-2. Set of Alco PAs on the point of a passenger. Nice hardware.


Active Member
2-10-0, 2-10-4,2-8-0,4-6-2, 2-8-2,0-6-0, C-C,B-B .B-Bs tend to be the most tolerant (although older outside bearing Athearn had its share ) , One thing I have noticed on Athearn PAs , in the late 80's ? Athearn switched to the "new" inside bearing truck to allow more play in the axles , unfortunately it was a little to much and some of my PAs the gears un-mesh causing pronounced axle hop and binding . It may be due to warping of the truck case ,either way the axle hop more than enough to pick the wheel up and set the flange on the railhead.

I am kind partial to 2-8-8-2 ,
Back on topic, re: 4 or 6 axle engines after the peanut gallery came in...

I don't have a preference but rather follow what the real railroads that I am interested in.

My favorite RR, D&RGW, had both 4 and 6 axle loco's and freely intermixed them, mainly on freight trains. Coal trains favored six axle sets but four axle loco's were also sued sometimes.

As for SP, my other favorite RR, they used pretty much all six axle engines on the route through my home town and over Donner Pass. The only 4 axle diesel I recall was a GP9 used in Davis to switch the Hunt Wesson tomato plant.

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