Calcs and info about scale for T gauge

marmot Aug 10, 2019

  1. marmot

    marmot TrainBoard Member

    I needed to figure out what scale I should use to generate some 3D prints of locomotives and passenger cars that I am adapting from larger scales. During this process, I have been forced to resolve the track gauge versus model scale versus prototype dimensions. I believe I have "rung out" one piece of misinformation related to the prototype gauge.

    I have measured and calculated a few different ways to convert larger scale models down to T gauge. I know T gauge is defined by the 3 mm gauge, not the scale. So I understand there are a few different scales utilized for T gauge. I know Eishindo (the manufacturer) says it's 1/450 scale on 3 mm gauge. The piece of info that is basically a square peg that is forced into a round hole is when anyone says the reference prototype is 3 feet 6 inches. Any way I calculate it or try to rationalize it, the 3'6" bit of info strongly disagrees with the 1/450 scale. It's WAY off - closer to 1/355 scale needed for 3'6" (1067 mm). Simply take 1067 mm divided by 3 mm = 355.

    I happen to be modeling a prototype with 3'6" gauge. That's why this clash of info matters to me. So I can't just be lazy and accept the tidbit about 3'6" gauge.

    Mark Watson's stated scale of 1/480 makes a whole lot of sense to me now for 4'8 1/2" (1435 mm). In fact, that helps to re-inforce that my various calcs are correct.

    The 1/450 scale for 3 mm gauge means the theoretical prototype was roughly 4'5". I see on a wikipedia page for Japan's railways that 3'6" is the most common, but they also have some 4'8 1/2" and a little bit of 4'6". Japanese track gauge is about halfway down this wiki page:

    I see on Eishindo's web page that they say T gauge is 1/450 scale. They never say anything about 3 ft 6 in or what the prototype track gauge was.

    I think it's very possible that they chose the 1/450 scale to go along with their existing 1/450 scale airport series. As of August, 2019, they haven't updated their web site since 2008 based on their posted schedule of upcoming exhibitions in 2008. They had existing 1/450 scale aircraft and airport accessories back then.

    My conclusion: Since the large majority of Japanese railways use 3'6" gauge, someone later inserted an incorrect assumption that the 1/450 scale is somehow related to Japan's most common 3'6" gauge. As I now see it, any reference to 3'6" gauge is misinformation relative to T gauge. I think their selection of 1/450 scale was somewhat arbitrary, so it makes the most sense to me for modelers of U.S. standard gauge to say it's 1/480. My awkward situation of trying to model 3'6" on T gauge means I should ideally try to stay closer to 1/355 scale, although this might be futile because the limited selection of motorized chassis and wheels means the size of the trucks/bogies/wheels will probably look ridiculously small relative to the rest of the cars and locomotives. Just to make it look decent, I might have to throw in the towel and just get it to look decent with whatever scale works on those chassis'.

    Please let me know if you agree or disagree or if you have any additional info. Thanks!
  2. martink

    martink New Member

    I just took some rough measurements of the models of the UK HST, and their bodies are to 1:440 (+/-10). Since there isn't all that much in RTR, it is probably best to pick something as your reference and build everything to match that. 1:480 from the track gauge is one obvious choice.

    Sadly, UK modellers are used to distorted gauges and scales due to the historical dog's breakfast of HO/OO/EM/P4 and the way this infected the neighbouring scales. Aussie modellers have similar problems since we use standard HO or N to represent Victorian 5'3". Sigh.

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