Thinking About Stopping
An introduction to industrial history
The very idea of air brakes may cause your eyelids to droop, but on 5 March 1872, the Unites Staes awarded a patent to George Westinghouse for his triple-valve air brake system for railroads, inspired in part by Elisha Otis' elevator brake that dated from the 1850s.
Dull as dust, right? Well...
By the mid-19th century, railroads the world over were expanding exponentially, and so were accidents. Most trains used either a mechanical linkage to operate any brakes they had, or used a brake car at the back of the train to slow the vehicle, adding to the reversal pressure of the locomotive and its own steam brakes. But as the trains got longer, it got harder to stop them. On long trips through desolate areas, the brakeman fell asleep or the signal device failed.
Stopping a train depended on more human input than the engineer signalling a need to stop.
Westinghouse's brakes were unique not because they were air actuated, but because they were spring actuated; they were (and are still) air released. Almost every air brake today in trains, trucks, cranes (yes, cranes), construction equipment, even elevators (using a hybrid system) operate on the theory that the stopping system has to be operating for the vehicle to move. The air system has to be pressurized, and the controls and drive train available to operate the vehicle. But with Westinghouse brakes, all that ended. The engineer hit the brakes, releasing the pressure on all the brakes on the train, and they stopped the vehicle.
Westinghouse brakes activated when the system failed, increasing safety.
While it was the Americans that invented the air-release brake, it was Europe that first exploited it more completely. Answering the need for an air supply, Britain mounted a diesel engine in a car immediately behind the locomotive tender to drive a compressor to pressurize the main air tank. Diesels burned oil rather than coal, sparing the need to shuttle coal into a furnace to maintain the system. As the technology improved, they built oil-burning locomotives with compressors, and finally diesel-electric locomotives emerged after WWII with stand-alone compressors.
Today's railroads rate diesel-electric locomotives by how much weight (in tons) they can stop in a fixed distance, not how much they can pull.
As safety improved, so did the size of the trains. So did the size of construction equipment, especially with the emergence of Clessie Cummins after WWI. Trucks and other heavy vehicles developed other braking systems, including the engine (reverse compression) brake, sometimes called a Jake Brake after the best known maker—that’s the loud roaring you hear sometimes as trucks try to stop.
Westinghouse (and Otis, differently) started engineers thinking about the consequences of getting large machinery moving, and better how to stop them.
Modern large vehicles, from the mine pit to the railhead to the grocery store to the road construction project, all use one version or another of the Westinghouse brake. And that's worth stopping and thinking about.
Lesson One in Industrial History
I call this industrial history rather than the more common technological or scientific history because it’s not of invention, but of application. “Technology,” after all, by definition includes rocks tied to sticks. The modern abuse of the term “tech” restricts itself to electronics and their associated gadgets. The concept of science or scientific history is best restricted to hard science. “Industrial” history, I submit, should be the history of the application of both technology and science. Now, soon, we’ll talk about manufacturing history, a neglected and vastly under-used field.
That’s my take and I’m sticking to it.
Who Wrote The Book Of Love?
On 27 August in:
1859: Edwin Drake’s first commercial well struck oil in Titusville, Pennsylvania. By the end of the century, the United States produced more petroleum and products than the rest of the world combined.
2008: The Democratic National Convention in Denver, Colorado, nominated Barak H. Obama for president; the first African-American* to be nominated by a major political party in the United States.
* Obama’s father was a black African; his mother was a white American. In the time (1960) and place (Hawaii) he was born, race followed the mother, so he was white by law. Obama did not identify himself as black/African-American until he was in high school in the 1970s.
And today is NATIONAL JUST BECAUSE DAY. Do something kind for someone just because.
Get your very own copy by subscribing!