7-1/4 vs 7-1/2 Gauge

Background
The 7 1/4 versus 7 1/2 Debate

As worldwide communications improved and it became evident that having two standards for 1:8 scale modeling in the U.S. was counterproductive, an attempt was put forth to adopt a true standard for track gauge, wheel profiles and couplers. The organization known as the International Brotherhood of Live Steamers was consulted, with representatives from areas around the world working with riding scale railroads. Via mailings, all known private and club railroads were contacted and asking for input on what the standards should be so a single set could be established. From the replies, it became abundantly apparent there was no easy solution within the U.S. and the I.B.L.S. settled on adopting and recommending standards following those being used in California and sent these out as "proposed standards" to everyone. Since these first included 7-1/2" as the correct gauge for 1:8 scale, they were never officially adopted by everyone and have remained as proposed ever since. However, in the U.S., these proposed standards have been used by most everyone for wheels and couplers and each area has used their local gauge standard. This has allowed for the trains to easily travel to other railroads and interchange equipment fairly easy, except for crossing The 1/4" Demarcation Line in the northeast. Today if you look at most IBLS wheel and coupler charts, you will find gauging standards for both 7-1/4" and 7-1/2" that have become the accepted standards by most. What is really most interesting is the fact that for exact 1/8" scale, the track gauge should be 7 1/16 inches.



Questions and Answers
Question: Someone once told me that the break in gauge between 7 ¼ and 7 ½" gauge started when Carl Purinton wrote a letter to Victor Shattock in the 1950's and accidentally typed 7 ½" as the standard instead of 7 ¼". This seems to be the most plausible story out of all I've heard (including some conspiracy theories) and I wonder: is there any truth to this or is it just another urban legend?

Answer: From Ken Shattock, 23 March 2013

In regards to your question about the 7 1/2 vs. 7 1/4 inch gauge controversy, I don't recall anything about a "letter" between Carl Purinton and my grandfather, Vic Shattock. However, just this evening (March 23rd) while going thru old records of our GGLS club history, I cut out the notation from the GGLS secretary, in the 1956-1957 time period which mentions this gauge problem.


 * By August of 1956 discussion was underway as to whether a planned ground track at Redwood Park should be 7 1/4" gauge or 7 1/2". It was in this month too that Vic Shattock was asked to write a history of the club. A few months later, in November of that same year, Vic celebrated his 50th. wedding anniversary.


 * It is easy to forget that as well as being the oldest live steam club in the country GGLS has other notable attributes to be proud of. The August 1957 issue of the Callboy noted that the club had the longest 2 1/2" gauge track in the world!


 * In September of 1957 it was announced that 7 1/2" gauge had taken hold as the standard gauge on the West Coast and that would be the gauge that the club would use at Redwood Park. That adoption has led to many conflicts over the years. Obviously one cannot travel from coast to coast (or overseas ) with a large scale engine and expect to be able to run on all of the tracks belonging to all live steam clubs. In fact, only for the two smallest, passenger hauling, gauges can one find facilities everywhere on which to run.

Question: According to the stories I've read, the reason that the east has 7 1/4" gauge and the west has 7 1/2" gauge all started with none other than Walt Disney himself.

Answer: No. Walt Disney's Carolwood Pacific Railroad was built in 7-1/4" gauge according. See Carolwood Pacific Railroad - Wikipedia.

Arguments for 7-1/16" Gauge
The following appeared in The Miniature Locomotive, Jan-Feb 1953

I would like to offer a few remarks on the subject of "Gauge Dilemma" by Mr. Stephen Booth in the Nov.-Dec. issue of our paper.

The matter of standards are very important as Mr. Booth points out and I hope you will see fit to print my comments and encourage others to write in and progress this matter to establish satisfactory standards.

With regard to the correct gauge for 1-1/2" scale it should be 7-1/16" between rail heads and in my opinion it is the only proper gauge to use for the following reasons:



First, the majority of models made, excluding engines without trucks, are of the Atlantic, Pacific or other types having a four-wheel engine truck. If the prospective engine builder attempts to build an engine with a two-wheel leading truck, for example the Santa Fe large 2-10-4 to 1-1/2" scale, he will find that if the gauge of track is over the scale width the front crank pins will not clear the guides while the locomotive is negotiating a curve. In the design of large modern engines of this and similar types you are confronted with the following:

The large diameter cylinders with cylinder head flanges extending out to the road head flanges extending out to the road clearance line means that the cylinder transverse centers are fixed by the bore. The high piston thrust to be distributed over four or five driving axles will require wide guide bars, further reducing space between the guides and front drives. Ten, and very often eight, coupled engines are provided with lateral motion devices on the front driving boxes to assist in curving. Inasmuch as the rods barely clear the guides of the full size design when curving, the relatively sharp curves used in model practice would result in interference of moving parts if the gauge is over width.

Second, the gauge must be correct for the scale selected in order to produce the proper prototype appearance. There is no good reason to use an incorrect gauge as anyone having ability to build an engine can gague track to 7-1/16" width as easily as 7-1/2" width.

in so far as stability is concerned the difference between 7-16" versus 7-1/2" is not marked and need not be considered. In fact the stability of a locomotive is largely dependent on the design and effectiveness of the springing and equalization.

good stability has been obtained in full-size practice on railways as narrow as 2'-0" in gauge. it is freely admitted that speed are not high as compared with standard gauge lines but rather powerful engines can be produced for this gauge.  An American example that many may have observed are the former standard gauge D.&R.G.W. locomotives which have been cut down to operate on the 3'-0" narrow gauge lines and these engines are not particularly subject to derailment. To bring out the proportions clearly I have superimposed an Indian 2'-0" gauge clearance diagram over a New York Central clearance which is of smaller cross-section than most of our roads. The great width of the narrow gauge equipment with respect to track gauge is readily apparent.

Vernon L Smith 1928 Randolph Ave Topeka, Kansas

The Whysall Light Railway Theory
Keith Taylor sent this email on 25 March 2013:


 * The story that I hear how the gauge discrepancy came to be is a little different.


 * Back in the late 1930’s there was a railroad in Michigan called the Whysall Light Railway that was owned by a Mr. Horace Shaw. A Chicago area live steamer wished to build an inch and one half scale locomotive and he contacted Mr. Shaw to get the specifics of things like the track gauge. The Whysall Light Railways was 7 – ¼” and I know this to be true because all of the equipment still exists and is owned by Mr. David Booth in Michigan. However….when the Chicago area steamer contacted Mr. Shaw, he was told the track gauge was 7- ½”! There was a reason for this and this has also caused problems with tinplate toy trains. Mr. Shaw was a collector of tinplate trains. Tinplate train track (because of the tubular rail heads) is measured from the center of the rail to the center of the rail! Lionel for decades referred to their “Standard Gauge” track as being 2 – ¼” gauge, when it is in fact 2 – 1/8” gauge. The builder proceeded to build his locomotive to what he “thought” was the correct gauge.


 * When the Chicago area steamer finished his beautiful Hudson loco, other steamers in the Chicago area wanted build to the same 7 – ½” gauge so they could all run on each other’s tracks. When the folks in California started to become interested in 1.5” scale, they contacted the folks whose lines had been written up in the Miniature Locomotive magazine and the Modelmaker magazine…and these were the folks in Chicago. Back in the 1950’s this wasn’t much of a problem as not many folks traveled to distant locales to run their equipment.


 * While 7 – ¼” gauge is not correct to scale, it is a “standard” set at the turn of the 20th century by Henry Greenly in Great Britain.


 * 7- ¼” gauge became the gauge of choice here in the Northeast United States and Canada as the first locomotives of that scale here were imported from England.

An article entitled "Gauge Dilemma Another Answer" appeared in The Miniature Locomotive, May-June 1953, supports The Whysall Light Railway Theory.

The 1/2 of 15 Inch Gauge Theory
by Bill Donovan of Real Trains Inc, responding to "7 plus Gauge Debacle"

That is an interesting and well documented story. I knew Irene Lewis well and have been to the David Rose Layout. As a point the Rose layout still exists today and is 7-1/2 inch guage. This differs quite a bit from what I have been told. It is tied to England and the migration of the scale through the east coast. This is where 7-1/4 inch gauge still is used. There is another path to the development of 7-1/2 inch guage that was not due to errors. Before and after WWII there were a number of firms making park size trains. These were commonly in 15 inch guage. Being too large for most yards and expensive there was a desire to make something smaller. The simple solution was to simply divide everything in half and so 7-1/2 inch gauge. These were not scale models but simplified to save cost and so the gauge was not seen as any type of error. This also explains why we have 1" inch high rail in 1-1/2 inch scale. The 15 inch guage equipment runs on 12 pound mining rail which is 2 inches high.  For a 1-1/2 inch scale rail to be 1 inch high the prototype would have to be 8 inches high and as far as I can tell no rail was every made this size (there is crane rail but that is flat on top and not for railroads).  The other reasons for the 7-1/2 inch gauge do not explain this and so I tend to believe it more.

Unification
From Richard W. Symmes, Co-Founder (1967) of the North East Live Steamers


 * Some people recently have been having good luck using special frogs on their 7-1/2" gauge pikes which allow the operation of 7-1/4" equipment without further alteration of wheel sets. Nick Edwards in Wimberley, TX is an example that comes to mind. Nick has a marvelous 7-1/2" gauge track, and many have been the visiting locomotives from the northeast that have run successfully on it.  So there is a way to make tracks accept equipment of both gauges.

An email from Bob Hornsby, received 25 March 2013:


 * Gentlemen:


 * There are many stories about why the gauge changed from 7-1/4 inches to 7-1/2 inches. I can also relate a few stories, but what does it matter now because, for the most part, there is harmony in the hobby.  We will never know the REAL reason for the mix-up, and if we did, the damage is done.  It’s water over the dam.


 * Nick Edwards had a dual gauge track in Nashua, New Hampshire that worked flawlessly. He moved to Texas, and so did I, where we built a new railroad with nearly three miles of track.  All of it is dual gauge.  We run trains mixed with 7-1/4” and 7-1/2” gauge in the same train without a problem, locomotives and cars.  The late Bill Fitt also had a dual gauge track in Michigan.  We have been running this dual gauge now for over 12 years without a problem.  It works!  If anyone is interested, I’ll tell you how.


 * In reality, 7-1/4 and 7-1/2 inch gauges are here to say, so what is the issue? So what if there is more 7-1/2” gauge.  Everyone is happy building and running trains.  Can’t we keep it this way?