Hi all… I have a question .I want to.what do the numbers indicate when buying a locomotive for ex…bachman 0-6-0 locomotive…what does 0-6-0 mean? I have a locomotive that is 4-8-4 and i try running it on an 18" radius track and it always derails…I am frustrated and looking to buy another one but i dont know what to look for…Im using bachman e-z track…in my layout…
stephen Lisiecki
These designations only apply to steam engines. They indicate the number of pilot wheels, drivers and trailing wheels. So, a 2-6-4 engine has two pilots, 6 drivers and 4 trailing wheels. Note that it’s wheels, not axles, so the number will always be even. Larger steam engines may have two sets of drivers, as in 4-6-6-4. These would generally be “articulated” engines, where the driver sets can turn with respect to each other to take tighter turns.
As for the derailment problem, it might be the long wheelbase of the 4-8-4, or it might be the trackwork itself. Steam engines, because they have a lot of wheels, can be very fussy about good trackwork. They often will find bad spots that everything else traverses without a problem.
You have to watch the locomotive carefully as it approaches the spot where it derails. What comes off first? Is it only a few spots on your layout, or does it come off the tracks all over the place? Is the curve smooth, or is there a kink at a track joint? Is the track perfectly flat, or is there a slight change of slope, particularly at a rail joint?
You may find that the 4-8-4 can perform just fine on 18-inch curves. I have a 2-8-2 (Mikado) steamer that is no problem on my own 18-inch curves, so I would look carefully at the track before blaming the locomotive.
Take a look at this article. It will give you an understanding of wheel configurations on steam engines.
Which company built the locomotive, by the way? Someone here will probably have personal experience with it, and can tell you if it really can’t handle that radius.
[#welcome] Glad to have you aboard.
The numbers you refer to are the Whyte classification system, which counts wheels. Our European brethren count axles, so your derailment-prone Northern (Niagara, Dixie, Golden State…) would be a 2-4-2 in that system.
A Northern (by any name) is a long, stiff locomotive, even though some HO scale model manufacturers have made their products loose enough to round perfectly-laid 18 inch radius curves (while looking seriously ugly doing it.) The key is perfectly-laid track. The least hint of a kink, bump or dip and she’ll be on the ties. Note that curves with much greater radii would have been speed limited down to 15 MPH on the prototype.
Another factor is whether or not your curves have spiral easements. The abrupt transition from tangent to curve inherent in sectional track is a prime source of tracking problems.
Even with spiral easements into perfectly-laid curves, 18 inches is too tight for a lot of HO 4-8-4 locomotives. Brass models, especially, were seldom capable of taking less than 24 inches.
Going all the way back to that Bachmann 0-6-0 - if it’s the 0-6-0T, that’s a model of an Alco `Catalog’ loco built in 1910 for light/industrial switching. If a railroad or industrial plant wanted one, Alco would just pull the blueprint out of a drawer and build it. At that time, most locomotives were custom-designed to fit the purchasing railroad’s standards and conditions - but this one isn’t.
Chuck (Modeling Central Japan in September, 1964 - with a Bachmann 0-6-0T in service)
[#welcome]
The 4-8-4 also called a Northern usually has larger drivers than a 2-8-2 or 2-8-0. This means the wheelbase of the drivers is longer and this in turn requires a larger radius. As others have noted, some but not all manufacturers have enough play in the drivers so it will get around 18". Some also have blind (flangeless) center drivers which allow for sharper curves…
The 0-6-0, 2-6-0, and 2-6-2 are older with smaller drivers making them well suited for sharp curves.
Good luck
Paul