Space Shuttle and Roman Chariots

[Chris Nahr]

This is probably old but I haven't seen it before, and I found it quite fascinating (assuming it's true):

The Space Shuttle and the Horse's Rear End (http://www.astrodigital.org/space/stshorse.html)

Linked by a commenter on Eric Lippert's blog.

[Fugitive]

SNOPESED! (http://www.snopes.com/history/american/gauge.asp)

[Chris Nahr]

That's a weirdly angry non-refutal. So the axle width was similar not just for Roman war chariots but for all kinds of wagons drawn by two animals. That makes sense but I still think it's fascinating that the maximum size of rocket boosters that are transported by railway is ultimately limited by the width of horse-drawn carts!

[Aeon221]

That's a weirdly angry non-refutal. So the axle width was similar not just for Roman war chariots but for all kinds of wagons drawn by two animals. That makes sense but I still think it's fascinating that the maximum size of rocket boosters that are transported by railway is ultimately limited by the width of horse-drawn carts!

Uh, they aren't? There's no such thing as a tunnel only slightly wider than a train track.

The railroad from the factory runs through a tunnel in the mountains. The SRBs had to fit through that tunnel. The tunnel is slightly wider than a railroad track, and the railroad track is about as wide as two horses' behinds.

I mean, really? A tunnel in the mountains? And I bet NASA had to look out for people trying to head off their train at the pass too.

[Jakub]

I like how snopes refuses to allow click-drag selection. As if a simple CTRL-A or right-click select all doesn't defeat that.

[WarrenM]

I like how snopes refuses to allow click-drag selection. As if a simple CTRL-A or right-click select all doesn't defeat that.
I noticed that as well and it pissed me off. What makes your content so special? Fuck off.

[Linoleum]

Some visual reference of the segments and shipping containers (http://www.nasa.gov/mission_pages/shuttle/behindscenes/srb_inspection-gallery.html)

[Ben Sones]

Uh, they aren't? There's no such thing as a tunnel only slightly wider than a train track.

Not only that, but the bore of the tunnels is not actually determined by the gauge of the tracks. It's more a matter of the width of the rolling stock, and how far apart parallel tracks are set. Cecil Adams (http://www.straightdope.com/columns/read/2538/was-standard-railroad-gauge-48-determined-by-roman-chariot-ruts) weighs in:

...Another version of this legend adds the rococo touch that the solid rocket boosters (SRBs) used on the space shuttle are manufactured at a Thiokol plant (I presume in Utah), then shipped to Florida by rail for final assembly at the launch site. The rail line passes through one or more tunnels en route, and the SRB pieces had to be made small enough so they'd fit through the tunnel bore. Thus, the legend triumphantly concludes, the dimensions of one of our most advanced vehicles was determined by the size of one of our most ancient!

True? Again, yes and no. A NASA spokesperson confirms that railroad tunnel dimensions were a constraint that had to be taken into account when designing the SRBs. However, tunnel dimensions are less a function of track gauge than of rolling stock width. U.S. railroad cars are quite a bit wider than those in England because parallel tracks are placed farther apart. (I'm talking tracks, not rails here, capisce?) As a consequence, U.S. railroad tunnels typically are wider too. So you can't really make the case that the size of the space shuttle's boosters was determined by the width of a couple horses' butts.

[WildElf]

I like how snopes refuses to allow click-drag selection. As if a simple CTRL-A or right-click select all doesn't defeat that.

Well, since I never want a single word or the entire page, it works pretty well to defeat me.

It's so annoying to open up the source every time I want a text quote.

[Chris Nahr]

Uh, they aren't? There's no such thing as a tunnel only slightly wider than a train track.

Of course they must be wide enough for regular trains cars, but horse-drawn carts could also have superstructures wider than their wheel gauge. Ultimately the maximum width is still constrained by the track width which is suprisingly narrow by modern standards.

I wasn't aware that America uses a wider track spacing than Europe but you still can't make the rolling stock arbitrarily wide if you have to run on a standard gauge. If you were to design a transport system for very heavy loads today you'd make the tracks two or three times as wide. You could fit 2-4 tracks with a much wider gauge in the space of a modern multi-lane highway.

So I think the point that modern railroad transportation is fundamentally constrained by ancient horse carts still stands, although the deduction isn't quite as neat.

[Aeon221]

Of course they must be wide enough for regular trains cars, but horse-drawn carts could also have superstructures wider than their wheel gauge. Ultimately the maximum width is still constrained by the track width which is suprisingly narrow by modern standards.

I wasn't aware that America uses a wider track spacing than Europe but you still can't make the rolling stock arbitrarily wide if you have to run on a standard gauge. If you were to design a transport system for very heavy loads today you'd make the tracks two or three times as wide. You could fit 2-4 tracks with a much wider gauge in the space of a modern multi-lane highway.

So I think the point that modern railroad transportation is fundamentally constrained by ancient horse carts still stands, although the deduction isn't quite as neat.

You could just as easily declare that the size of the railroad was determined by the width of two human asses. It's a specious process that has little to do with the actual determination of the gauge.

http://en.wikipedia.org/wiki/Rail_gauge

Note the variety of gauges. Note, also, that wagons and carriages are not necessarily 4.85 ft in width either.

[Chris Nahr]

The variety of other gauges is rather irrelevant. We're talking about the international standard gauge which, as another Wiki page (http://en.wikipedia.org/wiki/List_of_rail_gauges) will tell you, is far more widespread than any other, and does in fact constrain what you can transport on rail in most places. Greater wagon width only gets you so far because eventually the risk of toppling over is too great, and besides it's constrained by the spacing of parallel tracks. You won't ever see parallel 1.435 m tracks that are placed 10 meters apart -- those two measures are correlated in practice.

The whole point of the anecdote is that rail transportation today is rather severely affected by a decision made centuries ago based on obsolete technology, and that point still stands. Your Wiki page says that the standard gauge was considered "not too narrow and not too wide" -- but then immediately admits that a wider gauge of 2.14 m "offered greater stability and capacity at high speed", even at the time!

So why was the standard gauge so curiously narrow? Compatibility with existing horse cart measures seems like a perfectly plausible reason -- and indeed, that's exactly what the Snopes page says. Today we move much heavier loads at much higher speeds on railroads, so the ideal modern rail gauge would likely be at least twice the standard gauge, with a correspondingly wider track spacing of course.