A sixteenth of an inch is the only real difference between traditional O scale track and P48. It isn’t that much but in the 1950s that sixteenth of an inch often meant war between traditionalists and those who saw the potential of closer to scale wheels and a corrected track gauge. One needs to remember that there were few if any across the board standards in the early days and with wheels, it was still the Wild West. Marshall Dillon hadn’t cleaned up Dodge City yet.

P48 started with a desire for functional dual gauge turnouts, with the problem being the different wheel and flange profiles on standard and narrow gauge wheels. The two were basically incompatible.

In the 1950s Norm Buckhart and Dan Ranger, both narrow gauge modelers, were building an On3 model of a D&RG C-16 locomotive. This project led to the discovery of an 1890 Railway Equipment Guide that contained a thorough discussion of prototype wheel profiles and specifications.

This newfound knowledge led to development of the first prototypically accurate narrow gauge model wheels made by Al Henning. Al’s wheels had a tread width of 0.117”, a properly formed fillet between the flange and tread, and a flange depth of 0.028”. Seeing how well Al’s wheels performed, Don Graf had some standard gauge wheels made. They also ran beautifully and were compatible with the narrow gauge flangeways.

This solved the compatibility problems that plagued the construction of dual gauge turnouts. However, attempts to run ordinary standard gauge wheels over the new trackage proved disastrous. The standard flanges hit the spike heads of the smaller code 100 rail of the new dual gauge tracks, which aggravated the traditionalist members of the club where this all took place.

Group politics being what they are, the floodgates of controversy opened and a big disagreement ensued between the narrow gauge modelers and the other club members over which wheel specs to use. In time, the narrow gauge modelers struck out on their own to pursue the finescale wheels and accurate track, thus laying the groundwork for others in the future. Once they discovered that an accurate flange profile would track well for standard gauge, they also decided to complete the picture and use the correct track gauge. Remember, traditional O scale track was and still is too wide, a result of some bastard compromise in the dark ages of the hobby.

P48 Growth
Development of the new wheel and gauge standards grew in fits and starts as more products became available from dedicated individuals who believed in the work. Finally, in the 1980s, after nearly three decades of work to advance finescale modeling standards in quarter-inch scale, a set of specifications for accurate wheel and flange profiles based on scaled down dimensions from the prototype was finally recognized by the NMRA. This also included the accurate track gauge. The new specs became known as Proto 48. The term “proto” was chosen for its applicability to other scales, which also had proto-based movements such as Proto 87 and Proto 64 in HO and S scales respectively.

Modeling Is Modeling
I’ve never quite understood the mythology that has developed around finescale standards. When I was editor of O Scale Trains Magazine, we would get dissenting mail every time we ran P48 material; not a lot but we could always count on some. O scale is hide bound by tradition and many older modelers saw it as a threat of some kind. It’s understandable I guess when you have a lifetime of accumulated stuff that you’re afraid will become obsolete if the new kid gets too popular.

What I still don’t understand is the knee jerk reaction many people have to any form of finescale standard. You can routinely expect declarations of how that stuff will never work, or won’t work for a basement size layout. It’s too fussy, too hard, too expensive, too this or too that. Of course, most of this is nonsense and ill informed opinion. It’s all modeling, regardless of the standard involved. No one objects to the NMRA standards, so what’s the big deal with finescale?

Today, P48 has come into it’s own. You can get started with relative ease but be prepared to enter a different world from the want it, go buy it ease of HO or N. P48 has a good supply of essential products like trucks and wheel sets in a variety of styles and diameters, along with accurate working couplers and even flex track with the correct gauge but you’ll have to do a bit of legwork to find them. Plug and play commercial turnouts aren’t available as yet, and I for one, don’t see that as a hindrance, because modelers who are drawn to this standard are usually experienced and can easily make what they need either from scratch or by using the excellent castings that are available. There are customer builders who offer handlaid turnouts in a variety of frog numbers and rail sizes, so you don’t have to lay your own if you really don’t want to.

Protocraft, run by Norm Buckhart, is the essential source for P48 wheels, trucks and couplers. He also has a beautiful line of limited run brass freight cars and a growing line of steam era decals. Rich Yoder of RY models also has a great line of trucks and Jay Criswell deserves our gratitude for carrying on the Right-O-Way line of track details from the late Lou Cross. (Jay is modernizing the operation by bringing it online.) It’s not an exaggeration to say that working in P48 would be nearly impossible without the resources and supplies these individuals make available.

An excellent online resource is Gene Deimling’s Proto48 Modeler site. Here you’ll find an extensive list of suppliers and inspirational modeling. It presents a compelling narrative for P48 and is included in the links below.


Some Relevant Links


Right-O-Way Products

Proto48 Modeler

Rich Yoder Models

I would be remiss in not mentioning this volume of The Missing Conversation.
The Missing Conversation Vol. 03 From OST Publications