5 ms·

This comes up every so often, but is unfortunately not really true: https://www.snopes.com/fact-check/railroad-gauge-chariots/ https://www.snopes.com/fact-check

This comes up every so often, but is unfortunately not really true: https://www.snopes.com/fact-check/railroad-gauge-chariots/ https://www.snopes.com/fact-check/railroad-gauge-chariots/ Rail gauges are an interesting topic and there are a variety of gauges and many were experimented with over the years. Russia and Eastern Europe mostly runs on 1,520mm broad gauge. New Zealand and non-high-speed Japanese rails are 3'6". Wider gauges make trains more stable at high speed but require much larger corners, and vice versa.

malingo 7y ago
Obligatory link to Feynman's description of how a train stays on the tracks around a corner, having its wheels on fixed axles: https://www.youtube.com/watch?v=P1ww1IXRfTA#t=35m19s https://www.youtube.com/watch?v=P1ww1IXRfTA#t=35m19s
- EdwardDiego 7y ago
  That was a great video, I never considered railway wheels as (truncated) cones, I had always considered them disks. I love the implicit knowledge of real (as opposed to software) engineers.
JackFr 7y ago
Snopes rates it as partly true, and the author is a pedantic killjoy. It is broadly true that for 2000 years European vehicles matched their roads and adapting existing vehicles to new technology led to using axles that were the same size. Do other gauges exist? Of course. Are the true elements of this worth repeating? Sure. As an unrelated aside here’s Richard Feynman explaining why train axles don’t need differentials. https://youtu.be/WAwDvbIfkos https://youtu.be/WAwDvbIfkos
- jcranmer 7y ago
  Honestly, rating it as partly true is giving it too much credit. The only parts that are true are that a) the US adopted 4'8½" gauge largely from British standardization, and b) the 4'8½" gauge was chosen by extension of a pre-existing horse-drawn system. The moral of the story, however, is supposed to be that "the SRB was constrained by a Roman standardized wagon size by a long chain of events." And the first postulate is false before the chain can start (as far as I know, the Romans never standardized wagon sizes, not even informally--except insofar as you're going to end up picking roughly the same size, to within a foot or two, given similar constraints), while the last postulate is also false because track gauge does not determine loading gauge. It also appears, judging from what I can find, that the loading gauge is actually smaller than the SRBs anyways. So even the loosest version of the final step of the chain appears to be false. So what's the elements worth repeating?

malingo 7y ago

Obligatory link to Feynman's description of how a train stays on the tracks around a corner, having its wheels on fixed axles: https://www.youtube.com/watch?v=P1ww1IXRfTA#t=35m19s https://www.youtube.com/watch?v=P1ww1IXRfTA#t=35m19s

EdwardDiego 7y ago
That was a great video, I never considered railway wheels as (truncated) cones, I had always considered them disks. I love the implicit knowledge of real (as opposed to software) engineers.

JackFr 7y ago

Snopes rates it as partly true, and the author is a pedantic killjoy. It is broadly true that for 2000 years European vehicles matched their roads and adapting existing vehicles to new technology led to using axles that were the same size. Do other gauges exist? Of course. Are the true elements of this worth repeating? Sure. As an unrelated aside here’s Richard Feynman explaining why train axles don’t need differentials. https://youtu.be/WAwDvbIfkos https://youtu.be/WAwDvbIfkos

jcranmer 7y ago
Honestly, rating it as partly true is giving it too much credit. The only parts that are true are that a) the US adopted 4'8½" gauge largely from British standardization, and b) the 4'8½" gauge was chosen by extension of a pre-existing horse-drawn system. The moral of the story, however, is supposed to be that "the SRB was constrained by a Roman standardized wagon size by a long chain of events." And the first postulate is false before the chain can start (as far as I know, the Romans never standardized wagon sizes, not even informally--except insofar as you're going to end up picking roughly the same size, to within a foot or two, given similar constraints), while the last postulate is also false because track gauge does not determine loading gauge. It also appears, judging from what I can find, that the loading gauge is actually smaller than the SRBs anyways. So even the loosest version of the final step of the chain appears to be false. So what's the elements worth repeating?