Copyright 2000 T. Sheil and A. Sheil All Rights Reserved
When Lionel came back into production in 1946, they introduces two different sizes of O Gauge cars. Their regular O Gauge line was made up of ten-inch freights and fifteen-inch passenger cars. These are approximately 1/50 to 1/55 in scale. Then there was the cheaper, smaller O27 line. Lionel made these as 1/64 sized cars running on O trucks. Marx had also embraced the 1/64 over O' concept. For many years, the precise definition of O27 implied a 1/64 scale item.
Granted, in purely technical terms, O27 refers to the cheaper O track with 27" curves. Lionel first made it for their bargain "Winner" line in the pre-War years. Track notwithstanding, O27's postwar appearance was as a cheaper line of small trains that ran on O27 track. The trains themselves were 1/64, running on O trucks.
In recent years, manufacturers have caused confusion by calling any cheaper, less-than-scale car as O27. One prime example: K-Line's 1/48 scale M<P15 switcher is a key component in many of their O27 sets. Likewise, several have re-issued Classic ten-inch O Gauge cars as O27. Classic O is larger than O27.
For our purposes, O27 refers to 1/64 sized cars, while Classic or Traditional defines the ten-inch freight and 15-inch passenger cars. We need to get back to the correct definition, so as to avoid confusion when sizing our trains.
O Gauge is defined as track with a 1 1/4" distance between the outside rails.
The native scale of O Gauge, as accepted in the United States, is 1/48. That equates to 1/4 inch equalling one scale foot.
The preferred scale for O in Britain is 1/43.5 Fortunately, it is uncommon in the U.S. We refer to it as Britscale. This distinction is made for purely technical reasons.
The classic O Gauge cars are ten-inch freights and fifteen-inch passenger cars, as typified by the Lionel 6464 boxcar and 15-inch 60' Madison passenger car. Cars sized comparably are referred to as Classic or Traditional, and represent a separate scale unto themselves. They were made for 31" curves, and are NOT O27.
O27, as introduced in the Postwar years by Marx and Lionel, is a 1/64 scale car made to run on O track. Liberties are occasionally made for better running on the wider gauge. However, the base scale remains 1/64. O27 should not be extended to include re-issued Classic cars, or any low-cost item capable of handling 27" track.
Offscale refers to items that are much larger scale than 1.48. These include things like 1/32 scale handcars made to run on O track.
Non-scale refers to items that do not fit 1/48 scale, 1/64 scale or Classic / Traditional standards. That includes cars whose dimensions significantly deviate from accepted Classic, O27 and 1/48 standards. These include items which are too tall (e.g., some Railking items), cars made closer to 1/48 than to Classic sizes, etc. Anything not fitting within the 1/48, Classic or O27 ranges, yet not exceeding 1/48 or smaller than 1/64, is technically non-scale.
Examples of 1/48: Lionel / Williams F3, F7, GP9, FM, and all ranges fitting 1/48 standards
Examples of Classic: 6464 boxcar, 6400 K-Line boxcar, Williams boxcars, 15" Madison car, 15" aluminum streamliner and other cars within these ranges.
Examples of O27: Original Marx "scale" cars, Marx E7, K-Line / Marx "deluxe" cars, early Lionel O27.
Manufacturers need to be more precise when promoting sets and cars. O27 track is not enough to make an O27 set. Cars must be 1/64, locomotive must be between 1/55 and 1/64. It would be best if makers differentiated on advertising between Classic and O27 sizes.