O scale or ¼ “scale, in my opinion, is the absolute best size to model. With a ratio of 1:48, it makes the task of detailing and building miniatures of any kind much easier to accomplish. Most of us old-timers were introduced to model railroading when we found that first Lionel train under the Christmas tree many years ago. Those train sets usually consisted of some type of steam locomotive, 3 or 4 freight cars including a caboose, a circle of 3-rail track, and a transformer/controller. We, of course, did not notice the huge wheel flanges or large out-of-scale rails that were typical of these models. As I remember, that old locomotive had two speeds somewhere between 60 and 100 miles per hour-but I didn’t mind at all-It ran, and to a certain degree, I was in control of both its speed and direction. In that era, prior to WWII, Lionel and 3-rail tinplate railroading were in their finest hour and a large number of model railroaders were created by their exposure to these wonderful and colorful toys. Many are still fascinated by the multitude of operating accessories and less than scale appearance of these early models and devote their efforts to collecting them.
The term “O” has several variations in both size and definition of equipment. Lionel manufactures designations such as O, O-27, and super O. All of these run on 3-rail O scale track and are wired for a.c. operation. Others such as Atlas, make both 2-rail and 3-rail versions. 3-rail equipment is not compatible with 2-rail even though the track and wheel spacing are the same. D.C. voltage is used for 2-rail equipment and has insulated wheels while 3-rail does not and will create a short circuit when operated on dual rail track. In their original train sets, Lionel provided sectional track with curves of 31” diameter-probably because it allowed the track to fit on a 4’ x 8’ plywood sheet. In an effort to fit more track in this area, O-27 was developed, which has a diameter of 27”. O-27 cars are slightly smaller than O cars and will run on standard 3-rail track. The opposite however, is not true-O cars may have a problem trying to negotiate the tighter curves of O-27. After World War II, many manufacturers began to navigate toward more realistic and true-to-scale track and equipment. This gave rise to 2-rail operation and an increase in kits meeting the exact specifications of O scale.

O gauge means the distance between track rails measured from inside to inside and is defined as 1 ¼”. Purists may notice that when O scale measurements of ¼” per 1’ are used this distance scales out to 5’ between rails- a space that is at odds with the 4’ 8 1/2” standard for U.S. railroads. This fact does not seem to concern many modelers (myself included). O gauge track in the Lionel train sets of the 1930’s and 40’s is most aptly described as “tubular” and, with the center third rail, very un-realistic in appearance. To make their track look more like the real thing, Lionel invented “Super O Gauge” which used a smaller, black rail as the center conductor. Others followed suit, using small studs as third rail conductors.
The advantage of three rail operation is significant-especially where reverse loops are involved. Each outside rail is wired as a common return for the center rail which is alternating current and non-polarized. When entering a reverse loop section, a two rail D.C. circuit will cause a short circuit since positive and negative rails are switched and reversed but the center rail of the 3-rail track remains constant while each of the outside rails are electrically the same. Insulation of a section of the outside rail can be used to sense the locomotive wheels and automatically switch the reverse loop turnout to the proper direction. In the past the main disadvantage of three rail has been its oversized and un-prototypical appearance which limited it to the so-called toy train market. Recently, however, in order to attract more of the scale market, manufacturers have produced much more realistic looking 3-rail track. Some suppliers, such as GarGraves, make flexible 37” lengths of track.

2-rail return loop without polarity switching. Positive and negative switch creates short circuit.

3-rail return loop does not require polarity switch since all rails are the same electrically.
There has always been a part of the O scale community that was devoted to true scale modeling. They were not willing to accept the toy-like appearance of the early train models and the oversized tubular Hi-rail track. Model railroads began to appear with the third rail outside of the running rails. One of the earliest model railroad books was by Frank Ellison with black and white photos of his Delta Lines railroad featuring an outside third rail. The trains and track were realistic and not at all like the toy trains which were predominate at that time. Locomotives and cars were built from kits and track was hand laid. The outside third rail was a pick-up head similar to those used by electrified subway cars. Obviously a lot of modification was necessary to achieve the more realistic appearance of two rail track. In those days it was not easy to be a scale modeler unless you had the skills of a machinist. Not only did a modeler need to be mechanically inclined-He also needed knowledge of electricity to insulate and power the track properly.
Many modelers who started in 3 rail O scale have switched to 2 rail layouts because of their desire to model their trains with more accuracy. In the early days it was almost impossible to find scale replicas of locomotives and cars. Kits were little more than very basic materials that needed to be cut, filed, drilled and shaped and the finished product depended mostly on the skill of the modeler. Where steam locomotives were concerned, this required skill could be considerable. It was in fact, almost necessary to own a fairly well outfitted small machine shop. The breakthrough for 2 rail modelers came in the mid 1950’s when beautifully detailed brass locomotives from the orient arrived on the scene. Now the most difficult to obtain O gauge equipment was commercially available in unbelievable fidelity to the prototype. To the delight of the 2-railers the flow of faithful reproductions included unpainted and painted steam and diesel locomotives as well as some freight and passenger cars. In a few years however, the joy dissipated when the cost of brass skyrocketed and the models were unaffordable for the average modeler. I still own 10 steamers in HO scale brass which I purchased in the 60’s for less than $50 each.
O gauge trains were the only game in town in the 1930’s and 40’s but began to decline in popularity in the following years. This was probably due to the advent of HO scale, which was half the size of O scale and therefore allowed for a lot more railroad in a smaller space. The downhill slide continued through the 80’s when the scale almost disappeared from the modeling scene. Thankfully however, sometime in the early years of the 1990’s, O scale began to make a comeback. Today there is an increasing number of manufacturers producing both ready-to-run and kits for this great section of the hobby. For many years, the only way to collect equipment and structures was to either pay a large price for brass imports or build them from scratch. The list of new suppliers is growing rapidly and a fair amount of the rolling stock is available in kits of wood, plastic or resin-all of which serves to reduce the cost. The time when O gauge modeling was prohibited because of the expense is slowly drawing to a close.
Another argument against O was the fact that it took a lot of space and unless one had a huge basement or garage, it was difficult to model a good representative of a favorite railroad. This is not a valid argument since all model railroaders seem to bemoan the lack of layout space. Devotees, however, point out that even though the layout may be smaller, it will be more impressive because of the size of the rolling stock. Having visited several O gauge club layouts, I can vouch for the latter stance. If you have never seen a train in this scale winding around a curve with a string of heavyweight passenger cars, you cannot imagine the visual impact. For those of us who chose to model in another scale –we can only stare in envy. If you are considering this scale I would highly recommend that you visit a club or layout to gain the full effect of these hefty model trains in operation.
How to add finishing details to O scale structures.
The story of Lionel Trains
O scale manufacturers-Lionel, LLC, MTH, Atlas, and Weaver
O scale track-Lionel, Atlas, GarGraves, K-line, MTH
For a more detailed description of O scale model trains-check out this great website trainsoscaleus