Why is 4 feet 8.5 inches the gauge used?

[Anonymous]

Hey... I just want to know what type and weight of rail the Roman chariots ran on! [:D]

[Anonymous]

Another story I've read is that the fact that the SRB's were built in segments instead of one single long tube is that 80' is about the maximum length a rail car can be built and negotiate curves. While it's true that a longer booster could have been built and air transported (the pregnant guppies) there was an attempt at the beginning of the shuttle program to involve as many states and industries in the process to "so to speak" spread the wealth to keep as many congressmen in the yes vote column as possible.

Bob DeWoody

[Anonymous]

I thought it was used because that's how wide the wheels are apart.

[davekelly]

Rob,

Good point. But that begs the question - which came first, the rail or the wheel/axle set?

[marknewton]

QUOTE: Originally posted by modlerbob

Another story I've read is that the fact that the SRB's were built in segments instead of one single long tube is that 80' is about the maximum length a rail car can be built and negotiate curves.

How long are modern auto-rack cars? 89 feet? How long are the various types of articulated container cars? How long are the various specialised dimensional load cars? Much longer than 89 feet. Obviously that story is also untrue.

Cheers,

Mark.

[Anonymous]

QUOTE: Originally posted by marknewton

QUOTE: Originally posted by modlerbob

Another story I've read is that the fact that the SRB's were built in segments instead of one single long tube is that 80' is about the maximum length a rail car can be built and negotiate curves.

How long are modern auto-rack cars? 89 feet? How long are the various types of articulated container cars? How long are the various specialised dimensional load cars? Much longer than 89 feet. Obviously that story is also untrue.

Cheers,

Mark.

You can't articulate an 80' long tube. I live in central Florida and although I can't verify this story I did hear it from several NASA employees after the Challenger explosion.
But I do know part of their PR campaign about the shuttle was that it provided income in over 40 states for various reasons.

Bob DeWoody

[marknewton]

QUOTE: Originally posted by modlerbob

You can't articulate an 80' long tube. I live in central Florida and although I can't verify this story I did hear it from several NASA employees after the Challenger explosion.

I agree, you can't articulate an 80' tube. But you can articulate a freight car or cars, which can carry a tube of considerably greater length than 80'. Then you have a dimensional load, which is routed accordingly. The webpage cited outlines the procedures for the movement of dimensional loads on US railroads:

http://www.rica.org/index.html

With the best will in the world, the NASA employees you spoke to were probably not expert in the field of railroad freight car design, hence their thinking that freight cars over 80' long won't go around curves.

Photos of the SRB-carrying flatcars:

http://southern.railfan.net/flat/cars/loads/rocket/rocket.html

Some other images of dimensional loads

http://www.readingnorthern.com/photos/photo66.jpg

http://southern.railfan.net/flat/cars/loads/loads.html?

QUOTE: But I do know part of their PR campaign about the shuttle was that it provided income in over 40 states for various reasons.

I have no doubt that part of the story is true. The various reasons may be summarised as "pork barrelling"!

Cheers,

Mark.

[marknewton]

QUOTE: Originally posted by davekelly

Good point. But that begs the question - which came first, the rail or the wheel/axle set?

I once read an interesting technical paper that suggested the practical limit for making ***ed
iron axles in the very early days of railways was about five feet in length, and which the author *conjectured* was an influencing factor on the gauge.

I reckon that there is far more likelihood of it being a prosaic matter such as this, rather than some fanciful twaddle about "war chariots", that influenced the early railway builders.

All the best,

Mark.

[marknewton]

Oh dear, looks as though I have transgressed the forum's censorship policy.

The previous post contained a word - eff, ay, gee, gee, oh, tee - that is used to describe a bundle of sticks or rods, in this context a bundle of small diameter iron bars heated in a forge and hammered together to make a homogenous large diameter billet.

Mark.

[davekelly]

Mark . . . too funny. Reminds me of my brother in law who makes detailed drawing of beam joints for construction companies. A client called wanting to know why he hadn't got the drawing that were late. After much searching it was discovered that the client's email filtered out the email carrying the drawings because the subject line was "erection drawings."