Funiculars: A Slippery Slope
You normally want ramps to have a relatively low slope: it’s hardly going to cut back on the amount of work you need to do to get something to the top if it’s too steep.
Unfortunately, it sometimes isn’t possible to construct a shallow ramp, usually due to terrain. You’ve still got to be able to get up to the top, though, which is where funiculars come into the picture.
A funicular is essentially a pair of linked carts on rails going up and down a slope. Think elevator, but tilted to the side, and using each other as counterweights instead of having their own counterweights.
Funiculars take shockingly little power to operate, since you’re really only hauling up the weight of the load. In fact, some low-tech funiculars operate by filling water tanks at the top cart and draining them at the bottom, which pulls down the top cart and vice versa. They’re an extremely effective way to get around, and since they’re usually in the mountains, you usually get a great view as well, except when you go through a tunnel. You also get quite a few in mines.
Depending on the amount of space available, the carts might have separate tracks, or they may share tracks. When they share track, there’s generally a split rail in the middle of the run that diverts the carts around each other.
Unfortunately, a funicular was the site of the worst ramp-related disaster in history. (Yes, definitely worse than the countless groin injuries caused by ramps in sports.) The Kaprun disaster occurred on a large funicular leading up to a ski resort. One of the large trams used in the funicular caught fire while going up the tunnel. The resulting smoke billowed up through the tunnel, killing more than 150 people, largely through smoke inhalation.
The disaster turned out to be caused mostly by poor training and a fault in the tram car, but public confidence in funiculars remained shaken for some years. (Maggie wouldn’t let me ride the last one we saw, but I think I’ve finally got her convinced that they’re safe.)
Going Medieval on Our Ramps
I know I’ve kinda built up the idea about myself that I don’t care about medieval warfare, that I consider it an absurd waste of thought. And, well, generally speaking, you’d be right. I think it’s a distraction from the things that actually matter, like actual historical construction methods. I’m interested in how they put things together, not how they broke them.
That being said, some slightly interesting uses were found for ramps in war, specifically for the purposes of siegecraft.
The first use was actually pre-medieval, though it was used on occasion in medieval times. Siege ramps are huge earthen ramps built right up a castle or city wall, a cliff face, or other positions of strength. They’re about as absurd as you’d think: the builders are going to come under constant attack by the people above, resulting in a wasteful loss of life. It was really only used when the besiegers grossly outnumbered the besieged, were otherwise unable to break through the enemy defenses, and had little care for loss of life on their side. The Romans used it a few times, as did a few of the smaller empires before them, and a few of the smaller kingdoms they conquered.
The other use was in siege towers. These, at least, were constructed with a bit more safety in mind for the troops on your side: not that sending them over an enemy castle wall is, particularly, a safer idea. Siege towers, depending on the whim of the builder, were generally a bizarre hybrid of ramp, staircase, ladder, and watchtower, all built out of wood and canvas and stuck on wheels to roll right up to the castle walls, where troops could exit the tower directly onto those walls.
They also usually had sheltered positions for archers to fire from. Still absurdly dangerous, of course, but you at least had some shelter from enemy arrows, at least until you got onto the wall. They still were vulnerable to fire, which medieval people loved to use on each other.
All in all: I prefer my ramps for actual construction purposes.
Archimedes, Simon and Galileo
I gave simple machines a basic overview in my last blog. This time, I’m going to go more in-depth into the history of simple machines—specifically concerning ramps.
The ancient Greeks recognized three simple machines to start with: the lever, the screw, and the pulley. The man who came up with the idea, Archimedes, was a brilliant but crazy guy. Built crazy ancient super weapons to sink entire enemy fleets one day, then jury rigged an ancient precursor to calculus the next. He’s considered one of the greatest mathematicians of all time for a good reason. He’s the kind of dude who could have moved the world, if you gave him a long-enough lever.
The Greeks added two additional simple machines eventually, but they were still lacking the ramp somehow. (They didn’t know what they were missing out on.)
It actually wasn’t until after a millennia and a half after Archimedes that the inclined plane was finally included in the list. The fellow who did it? An eccentric but brilliant Dutchman named Simon Steven (an unfortunately boring name for a genius.) Simon Steven was another one of those nutty Renaissance-era polymaths who threw the curve for everyone else. Simon Steven was the first person to figure out the mechanical advantage of the inclined plane. He also invented a wind-powered land yacht that could outrace horses.
After Simon Steven completed the simple machine sextet, of course, the development of the science behind simple machines hardly stopped. Galileo Galilei, notably, was the first to figure out that they didn’t create energy but merely transformed it. Leonardo da Vinci also made some critical discoveries regarding calculating friction in simple machines; then he promptly left them unpublished in his notebooks. It took almost two hundred years for someone else to independently rediscover them.
Ramping Up Franz and Kinematics
Simple machines are the basis of industry. Well, sorta.
A simple machine is a device used to change the direction or power of a force applied to something in the simplest manner possible. There are six devices classically categorized as simple machines: axles and wheels, levers, pulleys, screws, wedges, and inclined planes (obviously the best).
The reason I said they’re only sorta the basis for industry, though, is that the idea of simple machines is itself an oversimplification.
First off, take a look at wedges and screws. A screw is nothing more than an inclined plane wrapped around a cylinder. When you’re turning a screw, picture it inside the material—climbing up or down the ramp—as the screw turns. Wedges are just two ramps hooked up to one another, bottom to bottom, for use in transferring force perpendicularly.
Ramps make up half of the classical simple machines. Ramps rule, but we already knew that.
Then you come to wheels and axles and pulleys. A pulley is just a wheel and axle with a rope attached. It’s still super useful, of course.
At first glance, our final classical simple machine, the lever, is pretty distinct from the others. A guy named Franz Reuleaux, however, realized that, like the wheel and pulley, the lever is just a body rotating about a hinge. Reuleaux was also the one who figured out that the screw, wedge, and inclined plane were the same. Really smart cookie.
So all in all, you’ve really got two simple machines and four variants on the original list. And that’s the first issue with describing the classical simple machines as the basis of mechanical industry.
The second issue? There are a lot more than six simple machines. You’ve got four-bar linkages and cranks, for example. Our good buddy Franz identified hundreds of simple machines using his self-invented science of Kinematics, which we still use today. Way to go, Franz. Not bad for a guy born in 1829.
Nowadays, thanks to Franz and Kinematics, we actually consider joints the basis of mechanics, but that’s a story for another day.