The Miniature Locomotive, November-December 1952
Increasing interest in 1-1/2 inch scale for outdoor miniature railroads has brought to the forefront the distressing fact that a fraction of an inch in gauge is preventing any interchangeability of rolling stock and motive power.
Live steamers across the country are faced with the problems of deciding between 7-1/2 inch and 7-1/2 inch gauges before they can start construction. Those who already have locomotives, cars and track are in a worse situation.
Just what is the "correct" gauge for this popular scale?
Those interested only in super-accurate models should scale down 4 feet 8-1/2 inch and put the rails exactly 7-1/16 inch apart. but such a dimension is too minute to be adhered to easily in track laying.
For this reason, many years ago in England, where the live steam railroad hobby got its start, 7-1/4 inch was chosen as standard. All 1-1/2 inch scale railroads in that country are still built to this gauge.
Slightly wider than scale to give more stability, and certainly an easier distance to measure, 7-1/4 inch was later adopted by early 1-1/2 inch scale live steamers in the eastern part of the United States.
Evidence of this is the fact that in New England, location of one-third of the steam locomotives in this scale, virtually 100 percent are being built for or are in operation on 7-1/4 inch pikes.
According to a recent survey, gauges of 1-1/2 inch scale steam locomotives in the entire nation are divided as follows:
- 7-1/4 inch - 52.5%
- 7-1/2 inch - 40%
- Other and unreported - 7.5%
Within recent years, a number of conscientious live steamers and several parts and castings suppliers have turned to 7-1/2 inch gauge. No one seems to be able to explain the reason.
Seven and one-half inches is, admittedly, a nice round figure even though it does veer far away (3-1/2 inch in prototype) from the correct gauge. But what are its advantages over the long established 7-1/4 inch? Is stability further improved to a large degree? Is track easier to lay?
Answers to these and other questions are lacking.
Sometime in the future, after a few live steamers tear their hair in frustration, a standardized gauge will probably be decided upon. But even after the decision has been made it will take a long time for the confusion to subside. The hobby will have benefited, though.