Thoughts From the Front Porch

Firebox and Drivewheels

Nothing bespeaks sheer power like a steam railroad locomotive.  This machine is alive even while sitting still; a real-life, fire-breathing dragon of unbelievable strength.  Steam engines do not struggle; they simply move with a force that can only be described as inexorable, absolute.

The most amazing thing about all this power is that it is produced by a pair of steel discs not much larger than automobile hubcaps.  How is such a thing possible?

Like any reciprocating engine, locomotives are driven by pistons which are housed within cylinders. You can easily spot these barrel-like objects, usually toward the front of the engine and connected to the main wheels with heavy steel bars.  Pistons & cylinders harness the pressure of expanding gases to generate their thrust; auto engines do it by burning fuel within the cylinders, whereas steam engines get their power from steam piped into the cylinders from a boiler.

A steam locomotive piston is typically a round disc, approximately eighteen inches to two feet in diameter.  Incredibly, this disc and its mate on the other side of the engine can produce thousands of horsepower and tens of thousands of pounds of “tractive force”.  How?  Well, like most engineering marvels, it’s all a matter of arithmetic.

Steam is powerful stuff.  It has an incredible ability to expand, exerting a huge amount of force from a relatively tiny amount of boiled water.  The hotter the steam, the more it can expand before cooling off.  Typical steam pressure in a locomotive can range anywhere from a hundred pounds per square inch to more than a thousand, depending on the engine’s design.  Most older engines operated at about 300PSI, so we’ll use that figure in our calculations.  Applying the pie-are-square rule, an 18″ piston has a total surface area of about 250 square inches.   If you push this piston with a force of 300PSI, you will get a total force of 75,000 pounds!  Remember, the pressure is figured PER SQUARE INCH.  And that’s just for one stroke of one cylinder; a steam locomotive has at least two, sometimes four cylinders.  Raise the steam pressure or widen the piston, and the power increases enormously.

Most locomotives have double-acting cylinders, so the steam pushes on both the forward and back stroke of the piston.  Also, they are timed so that at least one piston is always positioned to accept steam and produce tractive force.   Some are designed with separate high- and low-pressure cylinders so that steam that has exhausted most of its expansive power is then piped into a much larger cylinder with more square inches of surface area.

The hardest part of pulling a train is getting it started in the first place.  There may be millions of pounds of freight in a hundred or more railcars.  The engine itself can easily weigh more than a half-million pounds.  That’s when an EXTERNAL COMBUSTION engine really shines; it develops full power from the start.  Your car’s INTERNAL combustion engine must burn fuel within the cylinder to produce pressure that will gradually increase until it has enough force to move the piston.  Not so with an engine whose fuel is burned and pressure developed outside the cylinder.

Steam is most powerful when the locomotive is moving slowest.  It exerts maximum expansion when it can make the piston travel its full length before the spent steam is exhausted to the smokestack.

Once a locomotive gets up to speed, this power stroke is shortened a bit and the steam exhausted a little sooner to allow the piston to reciprocate more freely as it nears the end of its stroke.

Here’s a nice website that explains steam power in more detail: More.

When standing beside a steamer in a rail yard, you can hear the rumble and feel the heat from its firebox as puffs of live steam whoosh through the smokestack to maintain a draft for the fire inside.

Just before the train departs the station, a shot of live steam blows condensed water from its cylinders, which erupts at waist level as a hissing blast of white fog.  This is to keep the cylinders from being damaged because water, unlike steam, is not compressible.  As the engine begins to move, exhaust steam from its cylinders blows directly into the stack to produce that familiar choo-choo sound.

As I said in the opening paragraph, steam power is absolute; if the load is too heavy or the locomotive too light, its drive wheels will simply spin in place until friction improves enough to allow them to grip the rails.

Double Engine

One trick used by train engineers is to first move the train in reverse, which pushes all the slack out of the couplings between railcars.  If you’ve been around trains much, you’ve heard the machine-gun-like banging of cars being shoved against one another in this maneuver.  Then, as the train begins to move forward it only has to move one car at a time until the whole string is moving.

A steam locomotive in passing makes the ground rumble like a small earthquake.  Passengers enjoy a super-quiet, steady ride not possible in a car, bus or airplane. There’s nothing quite like it, whether you are standing beside the tracks or comfortably seated in a wide, softly upholstered reclining armchair with no seat belts.  My father once sat a while with me on a steam train I had boarded for a trip to Collinsville, AL.  It’s departure was so smooth that Dad didn’t even realize it was moving until he looked out the window. They stopped the train to let him get off, and he had to walk several blocks back to the station.

I was privileged to have ridden behind several steam locomotives as a child, and again as an adult on steam excursions sponsored by a local railroad club.  There are still a few places where one can experience this vintage thrill for themselves.  Here’s a couple of them:

Link 1

Link 2.

Don’t miss out on this, folks.  Once all these goliaths are scrapped, there will never be anything like them again.

Views From Benny Hill is a series by Jerry Smith

Views From Benny Hill

Remember those neat world globes we had in school?   I mean the kind with raised mountains that you could feel with your fingers.  Ever wonder just how authentic they really were?  Surely such mighty peaks would have to be much higher than those rows of little embossed bumps.  Let’s see if we can put it to scale.

Here’s some figures we can work with:
Earth diameter = 8,000 miles
Mt Everest = 29,000′ or about five miles
Mt. Cheaha = 2,400′  or about a half mile
Marianas Trench (deepest part of ocean) = a little over six miles
Empire State Building =  1,400′ with antenna, or about a quarter mile
Grand Canyon = one mile deep in places.

Now let’s find something we can use for our Earth;  ah yes, how about that nice, shiny bowling ball from PP3.   Being about eight inches in diameter, it gives us a perfect scale of 1″ = 1,000 miles.   Our next step: landscape the ball.   A little arithmetic brings us some surprising answers.

At our scale of 1″ = 1,000 miles, then .001″ must equal one mile.  Our lofty Empire State Building has suddenly shrunk to one-fourth of one thousandth of an inch!   That’s .00025, folks; less than half the diameter of a blonde human hair.  Heck, we could barely see it with a magnifying glass, let alone feel it on our globe.

The mighty Grand Canyon would be a slight scratch on the ball’s surface, about the same depth as the thickness of a sheet of toilet paper.  Our own Mt. Cheaha would protrude about one-half that height, and that’s above sea level, not the valley floor.   Mount Everest would tower a whopping .005″, or about the thickness of a playing card, and the Marianas Trench would barely catch a fingernail dragged across it.  Clearly, we need a much bigger ball if our globe is to be feelable at all.

In fact, if we don’t wash the bowling ball it will probably be far rougher than Earth’s surface at that scale, and the thumb hole would easily swallow almost everything east of the Mississippi into a pit nearly three thousand miles deep!   That’s all the way down to where the planet’s insides are made of molten nickel and iron.

To carry this comparison even further, the Earth’s crust, which averages about eighteen miles in thickness, would be roughly equivalent to five sheets of paper or about half the gap on an average spark plug.

Yep; our Earth is actually an extremely smooth place, covered mostly with oceans that amount to little more than condensation on a bowling ball.  It only seems magnificent to us because we are so incredibly tiny.

Views From Benny Hill is a series by Jerry Smith

Views From Benny Hill

Which causes more damage; colliding with a stone wall, or head-on with another identical vehicle going the same speed?  We hear it all the time–”they ran together with a combined speed of (whatever), so it’s no wonder nobody survived”.

If you recall a previous Phunky Physics story, a moving object must disperse all its energy before it can come to a stop.  If you have two such objects, both must lose all that energy; twice as much as one.  According to common belief, a head-on would be geometrically more destructive.  Is this fact, or an illusion?  Let’s do the science.

True, there is twice as much energy, but it is divided among two objects.  It’s possible to draw a theoretical line between both objects, beyond which neither will pass  because the opposing object won’t let it.  Therefore, all the energy of both objects will be dispersed on that line, but in no way shared by neither object.  The equal forces on both sides of said line assure that the line will remain still while those objects exert their kinetic energy on each other until all is used up.

Let’s assume that two identical cars begin moving straight toward each other from a dead stop.  Their speed reaches, say 60mph each, and they hit each other head-on.  Using our convenient “damage units” from a previous story, that means each vehicle has to dump 3600 DUs, total 7200DU.  If you divide that by the number of cars, it’s still 3600 per, which is the same energy either car would have expended by hitting our theoretically immovable wall.

This implies that the total expenditure of inertia would be the same as both objects crashing into an immovable stone wall, separately.  All the energy gets expended, and the impact point never moves.   For the damage to be any greater would mean that extra energy was created or transferred from somewhere else.  Simply butting two cars together won’t do that.

Makes sense, doesn’t it?

Views From Benny Hill is a series by Jerry Smith

Views From Benny Hill

Doc & Kathleen

Kathleen had always been attractive and she knew it. It seems she was born knowing it, but not in an arrogant sense of knowing she was beautiful. She’d just grown accustomed to being treated that way by man and woman, girl and boy, old and young.  It was just a fact of her existence. And she didn’t give it any more weight or importance than the fact of her hazel eyes.

She gave little thought to her looks or to her uncanny ability to attract. Sometimes she’d work all day in the her kitchen or her garden, with her hair pulled back out of her way and untidy, tendrils escaping as the air grew steamy and the work wore on. She didn’t consider paint and powder a necessity for the canning of green beans. She worked with no stockings on, like as not with bare feet, and in some frumpy garb. In a time when glamour was considered a woman’s most valuable commodity, Kathleen often didn’t care what she looked like. If she ran short of canning jars in the middle of putting up a batch of fig jam, she simply went after them as she was. Other women would’ve been horrified to be seen town without hair done and face made up, in a house dress, bare-legged and uncorseted.

In fact, for some reason, other women were slighted irritated that Kathleen sometimes took so little pride in her appearance. Kathleen didn’t care if she nettled the neighbor ladies or annoyed the WMU and the WSCS. She was much more concerned with the task at hand than the impression she made at the hardware store. She thought it was ridiculous to dress in finery for a housewife’s trip to town. It more or less proved that you didn’t have any better place to go. While women whispered haughty remarks about her shocking lack of chic, men would smile to themselves at how foolish women are. It should’ve tickled other women pink to have a point of pride with which she couldn’t compete. But the problem really was that she could.

When she felt like putting on the ritz, when she had a reason, Kathleen was the most fashionable and fetching woman in town. It’s fun for a woman sometimes to dress up when she has nice things that suit her well. And Kathleen did. She knew how to choose what looked best for her. She knew her own style. I heard a woman, who was younger than Kathleen, say that she sat at the corner drugstore drinking coffee many afternoons, hoping to see Kathleen come in so she could get a look at what she would be wearing. She said Kathleen had a way of wearing a garment that made every woman want one just like it. But nothing ever looked as good on anybody else.

Kathleen wasn’t just pretty. That wasn’t it at all. She had a vitality that animated those eyes and warmed her cream and pink complexion. She was intelligent and talented, fun and charming. I don’t know whether she learned charm, or if it just came naturally to her. But it began with one simple thing. And that one thing was a genuine interest in other people. Kathleen was interested in people. So they of course had no choice but to be fascinated by Kathleen.

As she grew up, Kathleen learned that she’d need defenses against some people, those who seemed unreasonably to fall in love with her. Men were drawn to her. Women wanted to be a part of her circle.  Life in a town of five or six hundred people means, simply, that until they move away or die, everyone is always there. You may as well learn to like the ones you can and endure the ones you can’t. But they must be dealt with. So Kathleen learned to evade most unwanted advances, skillfully, without causing a big fuss.

A few, mostly women, resented her charisma or magnetism, or whatever it was she had. Some, the ones with too little regard for their own value, were suspicious of her. They always, always thought Kathleen wanted their husbands or boyfriends for herself, when of course she had no interest in them in that way whatsoever. She was just interested in them each as individuals who made up her tiny sphere of existence. She might ask about a hobby or a inquire about a specific task she was aware of, or indulge in a running joke just to make the room warmer and keep a cozy conversation rolling. “How’s the fishing, Joe?” or “Still paintin’ that fence, Oscar?”

She could make a people laugh with a simple dry remark, because she timed it to be unexpected. Her timing wasn’t calculated. It was just a gift, a part of her nature. Then a wife would look at her husband and see his smile and suddenly feel inadequate. And unaware of their little drama, Kathleen had already moved on to the next thing. Sometimes a man would observe her attentions to other men, her small-talk questions and the earnest ear with which she listened, and conclude that Kathleen was “man-crazy.” A plainer woman doing exactly the same, he would’ve called very nice, or more likely, he wouldn’t have noticed her at all.

Men wanted what men always want to one degree or another: her attention. Some wanted only the casual company of such a woman. Once in a blue moon, it was something more threatening, more forbidden that they wanted, a certain kind of proprietary rights. They wanted to own her outright, by force if necessary. Most fell in the gamut between the extremes. The rare and really ravenous hovered around her circle like birds of prey, waiting for their chance to strike. She could see them coming from way off. She learned to bob and weave and laugh in the right places, as if they were all in on the joke, to allow them to save their faces and everyone to escape with grace. The message she silently sent was their only out: “You can’t be serious. Take this lifeline. There will not be another.” She could and would be more direct if her first lines of defense were breached. That was one of the most charming things about Kathleen. She had a little store of danger inside her that surprised people. And most folks loved and admired her all the more for it. “Don’t push me into that corner. I will not be pushed.” As a rule, people learned not to push.

It could have been Kathleen’s terrible, outspoken temper that cost her the early marriages. She was given to sudden fits of fury. She didn’t mind saying exactly what was on her mind. She didn’t mind defending her territory. Or maybe it was her magnetism. It’s hard on a man to see his wife in that way through other men’s eyes. Only the most secure, as very few young men are, could endure this awareness without desperate jealousy. One of Doc’s  most attractive attributes was that he was confident of his own worth. He was never jealous. Doc accepted Kathleen exactly as she was and understood her.

It was Doc’s own reaction to Kathleen that he did not understand. His first wife had been mild as milk. Kathleen was strong and fiery as brandy. She set alight an entirely new spectrum of emotions in Doc, both tender and furious. But he always remembered how she cared for him and took care of him, how she made home the only place he really wanted to go to. Like an Alabama spring, Kathleen could be delightful for long stretches. But the possibility was always there of a sudden storm followed by a cold snap and killing frost that gave way, without reason, on a golden morning when all was well again.  No logic could predict those storms of temper or explain her capacity to strike dread and devotion into a man’s heart as a hammer thunders into an anvil.

The first time Kathleen ran across Byrd Richardson after he’d taken Doc off to Memphis and left him there, she told him exactly what she thought of that hoodwink in great detail and sightly salty language. It happened to be on the sidewalk in front of the bank building. It drew the attention of a small but cautious crowd. They kept their distance and pretended not to hear. Byrd, unaccustomed to such hostility (or even disrespect) from anyone and especially a woman, was stunned speechless and humiliated. He experienced a sudden revelation. She was not afraid of him. He was afraid of her. This was an entirely new sensation for the favorite son of the county’s wealthiest family. He had always wanted to add Kathleen to his list of conquests. But now she’d unintentionally lit a holocaust in him. For once in his life he wanted something that he feared he would never get.

The Right Southern Corner is a series by Sara Rast
Copyright: 2009 Sara Love Rast. All rights reserved.

The Right Southern Corner