I have been looking for a new locomotive for my HO Scale layout. I currently have 4-axle road units, 4-axle switcher units, and a UP C424. The C424 works fine on my 15, 18, & 22 curves. But I am looking to buy another 6-axle road unit. One thing that I have rarely seen in locomotive descriptions are the minimum diameters for 6 & 8-axle units. Can someone tell me what the minimum diameter for 6-axle units is and any recommendations for models priced under $75.00?
Hey kyle,
I have two 6 axle locos from athearn. I have an AC4400 and I have a Dash 9 and each work fine on 18’’ inch curves. That is the absolute minimum radius you can have for 6 axle locos, now keep in mind I do not have any steam only diesel. Now you will need to install a long shank coupler on the end of the loco so it does not pull your freight cars off the track on the 18" curves.
Hope everyone realizes you guys’ use of dimensions is actually for the curve radius, not curve diameter which is twice times radius.
Mark
Even though many 6 axle units will run on that bare min 18" Radius (imagine diam is a mistake), you may experience problems with coupling to various rolling stock. The long shank will help, but they will not look that great rounding those tight curves.
If you still want those 6 axle units, just look to use shorter bolster centers and shorter units.
Trying to run big SD50/60s, Mac70/90s, AC4400s etc will undoubtably give you nothing but headaches. U33/36 may be boarderline. Units like SD7,24, 35s, RSD 12/ 15s, Maybe some Dash8 and C424s should be ok.
I say stick with Alco, I love the look of their diesels. I’m kind of wondering though why everyone is calling the C424 a 6-axle engine. Doesn’t it stand for Century class, 4 axles, 2400 hp? At least I haven’t seen a model of a 6-axle C424. But the 6 axle Century’s came in plenty of options. The 628, 630, 636, 855. I want to put 638 in there but I may be thinking of the MLW 638, I mean MLW did use alot of Century class stuff on them.
I also like the look of the gator nose RSD-15’s but I’m kind of in the same pickle as the OP, want to run 6-axle engines but don’t really have the room. Or the prototypical need but I’m freelancing so that gets booted right out the door. After all I am modeling a short line and if I had the roster I wanted it would be a shortline based on an island setting with about 10 engines, and that would just be the diesels! Lucky I’m going with DC huh.
“El cheapo [:O]”
What? Who said that! [D)]
Sorry, some times I get a little crazy with the smiley faces [:-^]
Mark, thanks for the clarification on the radius.
I also have 22 radius curves on my layout. Would this make any difference in the appearance or performance of 6-axle diesels? Any ideas or preferences on inexpensive models, say $70.00 or less?
Hi,
As you increase the radius, you will find your locos look and run better. Not sure what roads or type loco (other than 6 axle) you are looking for, but Athearn has always put out an excellent product for the money. Atlas may be a tad more expensive, but they have a quality loco and some excellent Alcos. Also, you might find some Proto 2000 (Lifelike) on Ebay for less money, and they make quality locos too!
Good Luck,
Mobilman44
Minimum diameter is 36" or 18r curve. I have Athearns, Atlas and Proto2000 6 axles and they all work on my layout and the minimum radius is 18".
I have almost all 18" radii (until my planned expansion…as soon as my wife can determine which house she wants to buy!)
A good 6 axle compromise are the EMD SD-45s (65 feet). [tup] My recommendation
A little longer are the SD 38-2s and 40-2s (68 feet)
and the Dash 8s and 9s (70 feet)
My Dash 8s are also Bachmann Spectrums. But they look a bit silly on the 18 " radii. They can be quite cheap on Ebay, and they should be, as they are poorly detailed and can be noisy.
The SD60s and anything later model is also a little silly looking on the 18" radii, but they can be made to work. You’ve got to watch out for low steps and the like hooking on switch machines on #4 turnouts etc. I had to move my switch machines back out of the way to run the SD60s and Dash 8s all smoothly.
Trainworld sells the Bachmann Spectrum SD45s and Dash 8s for $59.00 with the cheap decoders that you may want to replace with better.
They have the Proto 2000 SD45s for as low as $29.00 and SD38-2s for $39.00 right now. Those would be my recommendation if you like to do your own conversions to DCC (I forget if you mentioned you were DC or DCC?)
I think someone already mentioned something like the ALCO RS_C_ 3s and RS__D__ 4s & 5s etc. These are really compact little 6 axle units (55 feet) and I have a few dandy Kato models picked up on Ebay for between $40 and $60. Watch the model designation if buying sight unseen. The RS an RDs are only 4 axle models.
Hope this helps. Don’t be put off the small to mid-sized 6 axle units. They can be just fine.
(BTW C424s and 425s are always 4 axle units)
The magic radius in HO is 18 inches. All the train sets are sold with 18 inch curves and therefore all the HO manufacturers are strongly motivated to make their equipment run on 18 inch curves to allow them to sell to the proud owners of trainsets. Unless a larger radius requirement is printed on the out side of the box, the maker believes the unit will run on 18 inch curves. Or at least run well enough that the buyer won’t demand his money back.
Based on personal experience, four axle diesels and smaller steam (Pacifics and Consolidations) will handle 18 inch curves. “Handle” means stay on the track with a train attached. It does not guarantee that you can couple on a curve without using fingers to line up the couplers. I’ve never tried to run 6 axle diesels or big steam on 18 inches, so you are on your own there. If you are buying from a local hobby shop, the owner may be able to demonstrate operation in the store before you buy. As a general rule, 30 inch curves are broad enough to take anything. Performance on radius between 18 and 30 inches is variable. I would avoid going below 18 inches radius even for spurs and sidings.