[N8 v2.0]

Ok??? That makes very little sense, I think I need to see a picture. What is the equation for the solution? That's not a very 'real world' answer, because a you don't know the weigh of the cars a priori and you can't realistically change to superelevation to match the train as it passes. But I think it (the heavier cars pushing the lighter cars through the turn) is why they tend to put the empties at the back of the train.

oh hell.. i donno.. that was sent to me by our civil enginerd yesterday and so i stuck it on here...

Another nerd in my office came up with this:

In railroad surveys, the degree of curve is the angle subtended by a chord of 100 ft. The degree of curve and radius are related by:

D = 5729.6/R

If D = 2, then R = 2,865 ft

If velocity, v, is expressed in mph, then superelevation, e, is calculated by

tan Φ = v2/15R

If v = 70, then Φ = 6.5

Since the velocity is in miles per hour, assume the width between tracks is the U.S. standard railroad gauge: 4 feet 8.5 inches.

4 feet 8.5 inches? That is an exceedingly odd number. Why was that gauge used?

Because that's the way they built them in England, and the U.S. railroads were built by English expatriates. Why did the English build them that way?

Because the first rail lines were built by the same people who built the pre-railroad tramways, and that's the gauge they used. Why did "they" use that gauge then?

Because the people who built the tramways used the same jigs and tools that they used for building wagons, which used that wheel spacing. So why did the wagons have that particular odd spacing?

Well, if they tried to use any other spacing, the wagon wheels would break on some of the old, long distance roads in England, because that's the spacing of the wheel ruts. So who built those old rutted roads?

The first long distance roads in Europe (and England) were built by Imperial Rome for their legions. The roads have been used ever since. And the ruts in the roads?

Roman war chariots first formed the ruts in the roads, which everyone had to match for fear of destroying their wagon wheels. Since the chariots were made for (or by) Imperial Rome, they were all alike in the matter of wheel spacing.

The U.S. standard railroad gauge of 4 feet-8.5 inches derives from the original specification for an Imperial Roman war chariot. Specifications and bureaucracies live forever.

So the next time you are handed a specification and wonder what horse's ass came up with it, you may be exactly right, because the Imperial Roman war chariots were made just wide enough to accommodate the back end of two war horses.

And the answer is 6.4 inches.

 

[Westy]

http://www.trackplanning.com/superelevation.htm

 

[Shyrmp]

I am slowly starting to recall why I had to drop out of engineering. Funny stuff though.

 

[NapalmCheese]

A buddy and I met a couple of girls at a bar one night. Someone mentioned something about math and one of the girls said something like "As long as we're not talking about eigenvalues everything's good". At which point I recognized her as a fellow math geek and slipped her this note:

She laughed and politely declined.