Tag Archives: engineer

Crazy Judah

In 1857, a young railroad engineer named Theodore (nickname Crazy) Judah had a big idea: to connect the Atlantic and Pacific Oceans by a railroad that ran clear across the country. By that time there were railroads up and running in both the eastern and western parts of the country. The hard part would be running hundreds of miles of new railroad across the midwest—and finding a way through the Sierra Nevada Mountains.

Theodore first presented his ideas in Washington, DC but couldn’t get congressmen to all agree on legislation to make his railroad project a reality. He decided instead to get backing from private business people. In Sacramento he found backers and they became the Central Pacific Associates.

The next step was to go out and survey and map the route the railroad would take. Theodore was a civil engineer, so he knew how to survey land. He found a way through the Sierra Nevada range—by the horrible Donner Pass, named for the pioneers who had become disastrously stranded there one winter. When he finished it, the map was 90 feet long!


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Coal-hauling horses finally get a break

Whenever Cornish horses get together they like to sing in close harmony.

I know what you’re thinking: if Watt’s engine could turn a wheel, why not use it to propel a cart or wagon?

Excellent question! I’m glad you asked it. With a steam engine, pumps kept mines clear of water. Much safer for the miners and their animals who worked down there. Wait—animals? Well, yes. As the miners got coal loosened from inside the mine, they’d load it into carts. The carts were pulled by horses. Their wheels rested on 2 rails so the carts wouldn’t topple over as they were pulled up the rough surface of the mine floor.

Eventually, a kind-hearted soul looked at horses struggling to haul big, heavy loads of coal (or tin, or slate) and thought: there has to be a better way to haul coal. Corishman Richard Trevithick is credited for inventing the first steam locomotive. “On February 21, 1804, Trevithick’s pioneering engine hauled 10 tons of iron and 70 men nearly ten miles from Penydarren, at a speed of five miles-per-hour, winning the railway’s owner a 500 guinea bet into the bargain.”


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Archimedes and his odometer

Archimedes was a Greek mathematician who specialized in measuring space. He was certain that there must be a way to accurately measure how much space is in a circle—area—or how much space is in a sphere or a cylinder—volume (he figured out how to measure volume when he noticed that a certain amount of water spilled out when he got into a bath tub). Archimedes was influenced by other great mathematicians, like Pythagorus and Euclid.

Archimedes invented many wonderful machines, like a screw for drawing up water, or catapults that were used to fight off invading navies. Although we don’t have his plans for it, Archimedes is said to have invented a way to measure distance. This machine is called an odometer.

Archimedes’ odometer operated on the idea that every time a wheel goes around, it travels its own circumference. The odometer adds up those circumferences and marks when the wheel has traveled a mile. In our last post, we showed how a standard Roman chariot wheel goes around 42 times to travel a mile.

We know about Archimedes’ odometer because the Roman military engineer Marcus Vitruvius Pollio (80–70 bc – 15 bc), or Vitruvius for short, wrote about it in his 10-volume book De Architectura. Engineers build stuff. As the Roman Empire expanded, the army took along a corps of engineers to build fortifications; siege engines; bridges; tunnels; aqueducts to provide water; and roads. These engineers did such a good job that you can still find Roman bridges, aqueducts and roads today.

Emperor Caesar Augustus wanted to know exactly how big the empire was and decreed that mile markers should be put up along the newly-built roads. Vitruvius decided to build Archimedes’ odometer to accurately measure the miles.

We only know what Vitruvius’ odometer looked like from a fanciful drawing. We don’t know exactly how it worked. Some people, including Leonardo da Vinci, have come up with some pretty good guesses about how it worked. You can see Leonardo’s drawings here—plus, you can even download plans if you’d like to build one yourself! Now that’s cool.

We do know that every time the chariot wheel goes completely around, it moves other gears. The other gears are set up to mark a mile at the 42nd revolution of the chariot wheel. The trick is gear ratio—meaning some gears are bigger, some gears have more teeth. If the gear on the drive shaft has only one tooth and the gear holding the marbles has 42, the marble-gear moves 1/42 of a revolution every time the chariot wheel goes completely around. At the 42nd revolution, a hole with a marble lines up with a hole underneath the gear and the marble drops into a bucket. Each dropped marble represents one mile traveled.



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