compatibility

[3railguy]

With the exception of some prewar Lionel 027 engines and Marx engines with wheel gears that interfere with switch frogs, most O gauge trains by today's American manufacturers run on Lionel O gauge track. There is an issue with some accessories with clips that attach to the track or that require operating track sections.

Another thing to watch out for is minimum curve diameter. Longer engines and cars require broader curves and the minimum diameter is usually labled on the box and in the catalog.

[lionelsoni]

O27 is also available in 34-inch (Marx) and 72-inch (K-Line) nominal diameters.

[Chris F]

What set did you get? Recently, Lionel changes from "O-27" track (27" diameter circle) in sets to "FasTrack" (36" diameter circle). Any locomotives and rolling stock designed for 3-rail O-gauge operation, from any manufacturer, will work with the new FasTrack if it works with O-27 track. However, even some Lionel accessories will require modification (usually to the molded-in track ballast) when using FasTrack. One that comes to mind is the operating milk car.

As Bob Nelson mentioned, track is available with various curvatures, or diameters. For example, Lionel's are -
O-27 - 27", 42", and 54"
FasTrack - 36", 48", 60", 72"
O-gauge - 31", 42", 54", 72"

Larger engines and rolling stock (e.g., passenger cars) often need larger diameter track. Most manufacturers indicate the minimum curve required for a particular item in their catalog. This minimum also takes into account potential interference with a raised portion of a switch ("turnout").

Not only are locos and rolling stock generally compatible, very often the track is, too. Even when it looks like it would be impossible to connect two very different kinds of track, transition pieces are available.

[lionelsoni]

Not at all a simple question, as you can see at http://www.canit.se/~griffon/modrail/faq/r1gener.txt
"The Development of Model Railway Scales and Gauges"

In the US, 3-rail toy trains, like Lionel, MTH, K-Line, and Williams, all use the same gauge, 1 1/4 inches, and are generally compatible with each other. There are limitations, even within these brands, to how sharp a curve a train can tolerate. If you stick to conventional traditional ac operation, they are mostly compatible electrically too.

[nblum]

All freight and passenger cars, locomotives, and accessories made by Lionel, MTH, K-Line, Weaver, Atlas, 3rd Rail and Williams for three rail O gauge use should work fine with your Lionel track.

[Anonymous]

A very simple question from a newbie. I am using Lionel o gauge track with a Lionel set. What other brands, products are compatible with this. Is 0 gauge a common, denominator or is o gauge different from brand to brand. I know the track is different but what about trains, accessories etc.