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Why Are There Crushed Stones Alongside Railroad Tracks?

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Why are there crushed stones alongside rail tracks?

David S. Rose:

This is a good question with an interesting answer. The crushed stones are what is known as ballast. Their purpose is to hold the wooden cross ties in place, which in turn hold the rails in place.

Think about the engineering challenge faced by running miles of narrow ribbons of steel track on top of the ground: they are subject to heat expansion and contraction, ground movement and vibration, precipitation buildup from rough weather, and weed and plant growth from underneath. Now keep in mind that while 99 percent of the time they are just sitting there unburdened, the remaining one percent of the time they are subject to moving loads as heavy as one million pounds (the weight of a Union Pacific Big Boy locomotive and its tender).

Put all this together, and you have yourself a really, really interesting problem that was first solved nearly 200 years ago, and hasn't been significantly improved since.

The answer is to start with the bare ground, and then build up a foundation to raise the track high enough so it won't get flooded. On top of the foundation, you deposit a load of crushed stone (the ballast). On top of the stone, you lay down (perpendicular to the direction of the track) a line of wooden beams on 19.5 inch centers, 8.5 feet long, 9 inches wide and 7 inches thick, weighing about 200 pounds ... 3249 of them per mile. You then continue to dump crushed stone all around the beams. The sharp edges of the stone make it difficult for them to slide over each other (in the way that smooth, round pebbles would), thus effectively locking them in place.

The beams are made of hardwood (usually oak or hickory), and impregnated with creosote for weather protection. In the U.S. we call them "cross ties" (or, colloquially, just "railroad ties"); in the UK they are known as "sleepers"; European Portuguese, "travessas"; Brazilian Portuguese, "dormentes"; Russian, шпала (read "shpala"); French "traverses." While 93 percent of ties in the U.S. are still made of wood, heavily trafficked modern rail lines are increasingly trying alternatives, including composite plastic, steel, and concrete.

Next, you bring in hot-rolled steel rails, historically 39' long in the U.S. (because they were carried to the site in 40' gondola cars), but increasingly now 78', and lay them on top of the ties, end to end. They used to be joined by bolting on an extra piece of steel (called a "fishplate") across the side of the joint, but today are usually continuously welded end-to-end.

It would seem that you could just nail them or bolt them down to the ties, but that won't work. The non-trivial movement caused by heat expansion and contraction along the length of the rail would cause it to break or buckle if any of it were fixed in place. So instead, the rails are attached to the sleepers by clips or anchors, which hold them down but allow them to move longitudinally as they expand or contract.

So there you have it: a centuries-old process that is extremely effective at facilitating the movement of people and material over thousands of miles ... even though nothing is permanently attached to the ground with a fixed connection!

The ballast distributes the load of the ties (which, in turn, bear the load of the train on the track, held by clips) across the foundation, allows for ground movement, thermal expansion and weight variance, allows rain and snow to drain through the track, and inhibit the growth of weeds and vegetation that would quickly take over the track.

This post originally appeared on Quora. Click here to view.

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Big Questions
Why Do Baseball Managers Wear Uniforms?
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Basketball and hockey coaches wear business suits on the sidelines. Football coaches wear team-branded shirts and jackets and often ill-fitting pleated khakis. Why are baseball managers the only guys who wear the same outfit as their players?

According to John Thorn, the official historian of Major League Baseball since 2011, it goes back to the earliest days of the game. Back then, the person known as the manager was the business manager: the guy who kept the books in order and the road trips on schedule. Meanwhile, the guy we call the manager today, the one who arranges the roster and decides when to pull a pitcher, was known as the captain. In addition to managing the team on the field, he was usually also on the team as a player. For many years, the “manager” wore a player’s uniform simply because he was a player. There were also a few captains who didn’t play for the team and stuck to making decisions in the dugout, and they usually wore suits.

With the passing of time, it became less common for the captain to play, and on most teams they took on strictly managerial roles. Instead of suits proliferating throughout America’s dugouts, though, non-playing captains largely hung on to the tradition of wearing a player's uniform. By the early to mid 20th century, wearing the uniform was the norm for managers, with a few notable exceptions. The Philadelphia Athletics’s Connie Mack and the Brooklyn Dodgers’s Burt Shotton continued to wear suits and ties to games long after it fell out of favor (though Shotton sometimes liked to layer a team jacket on top of his street clothes). Once those two retired, it’s been uniforms as far as the eye can see.

The adherence to the uniform among managers in the second half of the 20th century leads some people to think that MLB mandates it, but a look through the official major league rules [PDF] doesn’t turn up much on a manager’s dress. Rule 1.11(a) (1) says that “All players on a team shall wear uniforms identical in color, trim and style, and all players’ uniforms shall include minimal six-inch numbers on their backs" and rule 2.00 states that a coach is a "team member in uniform appointed by the manager to perform such duties as the manager may designate, such as but not limited to acting as base coach."

While Rule 2.00 gives a rundown of the manager’s role and some rules that apply to them, it doesn’t specify that they’re uniformed. Further down, Rule 3.15 says that "No person shall be allowed on the playing field during a game except players and coaches in uniform, managers, news photographers authorized by the home team, umpires, officers of the law in uniform and watchmen or other employees of the home club." Again, nothing about the managers being uniformed.

All that said, Rule 2.00 defines the bench or dugout as “the seating facilities reserved for players, substitutes and other team members in uniform when they are not actively engaged on the playing field," and makes no exceptions for managers or anyone else. While the managers’ duds are never addressed anywhere else, this definition does seem to necessitate, in a roundabout way, that managers wear a uniform—at least if they want to have access to the dugout. And, really, where else would they sit?

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Big Questions
How Long Could a Person Survive With an Unlimited Supply of Water, But No Food at All?
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How long could a person survive if he had unlimited supply of water, but no food at all?

Richard Lee Fulgham:

I happen to know the answer because I have studied starvation, its course, and its utility in committing a painless suicide. (No, I’m not suicidal.)

A healthy human being can live approximately 45 to 65 days without food of any kind, so long as he or she keeps hydrated.

You could survive without any severe symptoms [for] about 30 to 35 days, but after that you would probably experience skin rashes, diarrhea, and of course substantial weight loss.

The body—as you must know—begins eating itself, beginning with adipose tissue (i.e. fat) and next the muscle tissue.

Google Mahatma Gandhi, who starved himself almost to death during 14 voluntary hunger strikes to bring attention to India’s independence movement.

Strangely, there is much evidence that starvation is a painless way to die. In fact, you experience a wonderful euphoria when the body realizes it is about to die. Whether this is a divine gift or merely secretions of the brain is not known.

Of course, the picture is not so pretty for all reports. Some victims of starvation have experienced extreme irritability, unbearably itchy skin rashes, unceasing diarrhea, painful swallowing, and edema.

In most cases, death comes when the organs begin to shut down after six to nine weeks. Usually the heart simply stops.

(Here is a detailed medical report of the longest known fast: 382 days.)

This post originally appeared on Quora. Click here to view.

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