Obviously there was a tendency to pick whole numbers in inches or feet for a railroad gage. Any exceptions raise a question of why they were chosen. Standard gage was an exception at 56.5”, and I have heard explanations as to how this may have originated with the .5” increment.
But what about a gage of 36.5”? Three-foot-gage was very common, and obviously a whole number. In railroad building, there is always an advantage in having a gage that is common to other railroads, if not for interchange, at least for the probability of obtaining used equipment in the same gage. So, if you are building so close to the extremely common 36”, why would you add .5” and thus eliminate the availability of probably any used equipment? Certainly .5” would not make any practical difference in hauling capacity. So why depart from 36”?
It is a natural assumption that for any railroad operation, track gage and equipment gage are the same. There needs to be some free play between the fit of the wheel flanges to the track, but this is typically accomplished in the profile of the flanges and the location of the wheel gage line in relation to that profile.
However, there is a practice of widening the chosen track gage for curves because curves inherently widen the wheel gage slightly. So here is the question: Were some particularly curvy railroad operations built with one gage for the wheels and a slightly wider gage for the track?
If that is the case, it introduces confusion in describing the system gage because it needs to be stipulated whether it refers to the wheels or the track. Gage is typically specified for a locomotive as part of its construction. However, there is the common assumption that a locomotive gage and track gage match. So a new locomotive built for a railroad system might be specified or designated as being the gage of the track—even if the locomotive had been built with a slightly wider gage for better curve clearance.
This is a potential point of confusion which I believe may have played a role in the gage debacle of the origination of the Hecla & Torch Lake Railroad at Calumet, Michigan. We had a discussion here about that a few years ago. That gage ended up as 49” stated as the system gage. There is further confusion in the statement of the president of the road when he explained the need to change the gage of the already-exiting track by one inch after receiving the first new locomotive.
In Doug’s list, there are two locomotives listed as 36.5” gage. My natural assumption is that the locomotives were actually built to this gage. If that were the case, it could not have been for better curve tracking on 3-foot-gage track, because widening the wheel gage would have been going in the wrong direction. For better curving on 3-foot-gage track, you would have to reduce the wheel gage to 35.5” rather than increase it to 36.5”.
However, there may have been a semantical ambiguity introduced by building a 3-foot-gage locomotive for a line that had been built to 35.5” for better curve operation. Specifically, instead of labeling the locomotive as 36” gage as it actually was; they may have labeled it as 35.5” because that was the gage of the track. So construction records show the locomotive as 35.5-inch-gage when it may have actually been 3-foot-gage.
The gist of all of this occurred to me in the thread here about Jones & Laughlin locomotive #58 being 23-inch-gage, and running on track referred to as 2-foot-gage.
