Moral Exemplars Still Wanted: "The Current War: Director's Cut"

One way of teaching engineering ethics that is less grim than picking through wreckages of failed projects is to portray moral exemplars:  engineers who did the right thing in a critical situation and benefited people thereby.  For example, William LeMessurier, a structural consulting engineer, played a prominent role in determining that the 60-story Boston skyscraper formerly known as the John Hancock Tower was unstable in certain types of wind loading.  The analysis he and his colleagues produced convinced the owners to install millions of dollars' worth of cross-bracing, and the building is still standing today. 

For many generations both in the U. S. and abroad, Thomas Edison was a heroic inventor whose ideas benefited millions.  In 1940, at the height of the inventor-as-hero period in U. S. history, MGM brought out a pair of panegyrics based on his life: "Young Tom Edison" starring Mickey Rooney, and "Edison the Man" with Spencer Tracy.  I must confess that seeing the the former film on TV played a disproportionately large role in my decision to become an electrical engineer, around the age of eight.

However, cinematic heroes today tend to be mainly of the comic-book variety, so when "The Current War:  Director's Cut" was finally released after a two-year delay connected with the fall of Harvey Weinstein, whose production company financed the film, I could hardly wait to see what a present-day director and actors would do with the raw material.

And some of it is pretty raw.  There was no hint in the MGM flicks that Edison was ever anything less than selfless as he enthusiastically searched for innovations that would be boons for humanity.  In particular, there was nothing about the admittedly sordid tricks he pulled to make George Westinghouse's rival AC system look like a threat to public safety, up to and including killing horses and pigs (but not an elephant, as was falsely attributed to him by some confused reports of an elephant's electrocution he filmed at Coney Island in 1903).  But in "The Current War," Benedict Cumberbatch's Edison is no one's idea of a moral exemplar, though he would qualify as perhaps an object of pity.

Just the kind of historic rabbit-trail I took you on about the elephant is one of the problems with the film.  Despite the director's thoughtful inclusion of little side-titles when new characters are introduced (I particularly liked "Nikola Tesla, futurist"), the people I saw the film with all complained that it was very hard to follow.  Although I have made somewhat of an amateur study of Edison, Westinghouse, and that era of the history of technology, I myself had trouble figuring out who was who unless the side-titles were there to help.  In particular, there was an older bewhiskered gent who seemed to be Westinghouse's technical Svengali, but who was only addressed as "Frank."  At the time I guessed it was Frank Sprague, who played a prominent role in early electric tramways.  But later in the film it turned out he was Franklin Pope, an "electrician" (which was what electrical specialists sometimes called themselves back then) who died, not trying to get Westinghouse's electric fan motor to work as the film implied, but in trying to fix a motor-generator installed in the home of his own basement.

As most historical films have to do, this one takes dramatic license with the facts, but stays reasonably close to the main narrative, which is the battle between Edison's first-to-the-market but ultimately unsuccessful DC system, and Westinghouse's cheaper and better alternative of AC, which is still with us today.  The climax of the MGM Spencer Tracy flick, which was Edison's invention of the light bulb, is relegated to a long speech by Cumberbatch at the 1893 World's Columbian Exposition in Chicago.  Westinghouse won the bid to light up the fair, and that triumph symbolized the end of the current war.  Westinghouse and Edison run into each other at the Japanese exhibit, and Westinghouse asks Edison what it felt like to invent the light bulb.  What ensues is perhaps the best piece of classical acting I've seen Cumberbatch do—no special effects, no superhero action, just a man painting a picture of a scene with words that answers the question better than any number of adjectives. 

Cumberbatch seems to be making a career of portraying emotionally peculiar geniuses:  first as the legendary Sherlock Holmes, then as the eccentric mathematician and code expert Alan Turing, and now as Edison.  Critics of the film say he does a good job of portraying our era's idea of the corporate genius:  the Steve-Jobs-type disrupter of the status quo who nevertheless betrays his usually-suppressed emotional life by playing back the voice of his dead wife on his new invention, the phonograph.  Edison's first wife Mary did die in the midst of the current war, which only added to his distress and frustration.  But he didn't let her death slow him down in pursuing his goals by whatever means he thought necessary, including secretly cooperating with a man who thought electrocution would be better than hanging condemned criminals.

I suppose I should have put a spoiler alert on that last paragraph.  But it's unlikely that too many people will see the movie just for the suspense.  To techno-nerds such as myself, who are familiar with many of Edison's lesser-known inventions, the film was a feast of seeing cinematic reproductions of things like the first kinetograph projector (an early form of motion-picture machine) and his electric pen for writing on paper for mimeograph reproduction.  And the film gets some humor out of the Edison family's alleged habit of secretly communicating with each other via Morse-code taps. 

But for the average viewer who has little or no prior knowledge of the era, I'm afraid the film will be a rather confused mish-mosh of mysterious devices, obscure motives, and hard-to-identify characters. A strength of the film is that everything takes place against a lovingly-reproduced CGI background of 1890s America, including a panoramic view of the Columbian Exposition, complete with the original Ferris wheel, that ought to be issued as a two-by-three-foot poster on its own.  I'm not sure what effect the movie will have on eight-year-olds, but don't look for there to be a flurry of young people flocking to be electrical engineers in about ten years.  Actors, maybe, but not engineers.

Sources:  "The Current War:  Director's Cut" was released on October 24, 2019, and stars Benedict Cumberbatch as Thomas Edison.  I referred to a review of the film posted at https://www.thewrap.com/the-current-war-directors-cut-film-review-benedict-cumberbatch-tom-holland/ for details of the delayed release, and also Wikipedia information concerning the 1903 elephant electrocution of Topsy.

The Quebec Rail Disaster: Nine Notorious Necessities

In the science of logic, a necessary condition for a thing to occur is a circumstance that will stop the thing from occurring if the circumstance is not present.  Having fuel in my car is a necessary condition for getting it to run.  No fuel, no go. 

In the study of industrial disasters, you often find that instead of a single cause, there are multiple interlocked causes, each one of which was a necessary condition for the accident to take place.  The longer the chain of necessary conditions, the less likely it is that all of them will happen in a way that leads to a problem.  This is one reason why such situations are hard to anticipate.  The disaster that struck the town of Lac-Mégantic, Quebec on the night of July 5 and 6 is just such a tragedy.  While the full details have yet to be investigated, by going only a little beyond what is known I can assemble a chain of nine separate conditions, each of which had to prevail in order for the accident to happen. 

Lac-Mégantic is a community of about 5,000 on the tip of a lake of the same name, near the Canada-Maine border.  It was founded during the construction of the Canadian transcontinental railway in 1884, and a heavily-used rail line still runs directly through the center of town and extends westward up a rather steep grade to the next town of Nantes.  About 11 P. M. on the night of July 5, a five-locomotive eastbound train consisting of 73 tank cars filled with crude oil, besides other cargo, pulled into Nantes and stopped.  The engineer, Tom Harding, was done with his day’s run and planned to spend the night in a hotel in nearby Lac-Mégantic.  Before he left for the night, he followed what was apparently standard procedure in securing the train:  setting the handbrakes on all five locomotives and ten freight cars, and leaving one engine running to maintain pressure on the air brakes.

Railroad air brakes were an invention of George Westinghouse, who had the clever idea that a loss of brake pressure, such as would occur if part of a train broke away and lost its air connection to the engine’s compressor, should apply the brakes.  The same basic system is used today.  Each car has an air storage tank that provides the actual pressurized air that is applied to the brake cylinders on each “truck” or set of wheels.  The air from the tank is valved to the brakes when the main-line pressure falls, either gradually for controlled braking or suddenly, as when a train comes apart. 

But each tank holds only so much air, and so the other function of the air in the line is to maintain pressure in the tanks on each car. 

By setting the handbrakes, Harding was taking extra precautions.  In principle, as long as the engine was running to maintain air pressure, the air tanks would stay pressurized and the brakes would hold.  Satisfied that he had done his job, he made his way to Lac-Mégantic and to bed.

At 11:30 P. M., a concerned citizen reported to the Nantes fire department that the one running engine was on fire.  Local firemen reported to the scene and rousted out the nearest available rail employee, who turned out to be a track worker unfamiliar with the operation of locomotives.  The firemen and the railway employee managed to turn off the engine and put out the fire, but no one re-started the engine after the fire, and everyone left the scene by midnight.

For reasons that remain to be determined, about an hour later the train’s brakes ceased to hold, probably because the pressure in the air tanks dropped after the engine and its compressor were shut off.  The steep (1.2%) grade combined with the heavy load to send the train accelerating down the line six miles (10 km) along a straight track that executes a sharp bend in the center of Lac-Mégantic, near a strip of bars where late-night patrons were enjoying themselves.  Several people noticed the train rushing past at up to 66 MPH (100 km/hr).  When the leading locomotives hit the curve, they left the track and landed a few blocks away.  But the easily-punctured single-walled tank cars ruptured and caught fire, turning Lac-Mégantic into an inferno.  At the time of this writing (July 14), thirty-three bodies have been recovered, and seventeen more persons are missing and presumed dead. 

For this tragedy to occur as it did, you had to have

1.  A long heavy train full of

2.  Crude oil or other flammable material in

3.  Easily-ruptured tank cars attached to an

4.  Engine that caught fire and was turned off by

5.  A track worker who didn’t know how to start it again, and

6.  A steep grade under the train, and

7.  The engineer asleep in a hotel where nobody could find him, who

8.  Set enough handbrakes to keep the train from moving under normal circumstances, but not enough under the peculiar conditions that prevailed, and

9.  A town built around the closest turn in the tracks downhill from where the train started to roll.

If any of those nine conditions had been otherwise, the accident would not have happened, at least not to the extent that it did.  A shorter, lighter train might not have overcome the fading brakes.  Tanks of a non-flammable substance would have caused physical damage, but would not have burned.  Special double-walled tanks that are recommended for use in crude-oil service but not required, might not have ruptured as easily.  If the engine hadn’t caught fire, it would have kept the brakes going.  If the railroad employee had known how to start another engine, the brakes would have worked.  If the track had been flat instead of on a grade, the train might not have rolled away.  If the engineer had left a note saying where to call him in case of emergency, he might have restarted the engine.  If he had set more handbrakes, it might have prevented the runaway.  And if the bend in the tracks had been in a cornfield instead of in the center of town, no one might have died.

These “ifs” are cold comfort to those who have lost family and friends in the tragedy.  But they show what a long chain of unusual circumstances had to come about for the accident to happen.  Investigations may show that using more rupture-resistant tank cars would have reduced the chances of fire.  And there will certainly be questions raised about the advisability of crude-by-rail, or CBR, as a means of transporting large quantities of crude oil, instead of politically controversial pipelines, for example.  Let’s hope that what engineers, regulators, and the public learn from this accident will help in preventing the next one.

Sources:  I referred to articles on the accident in The Globe and Mail at http://www.theglobeandmail.com/news/national/mapping-the-tragedy-a-timeline-of-the-lac-megantic-train-disaster/article13105115/ and The Guardian at http://www.guardian.co.uk/world/2013/jul/12/quebec-oil-train-crash-disaster-24-bodies, a blog by Lloyd Alter at http://www.treehugger.com/energy-disasters/what-caused-train-disaster-not-brake-failure.html,

and a blog in Railway Age by Tony Kruglinski at http://www.railwayage.com/index.php/blogs/tony-kruglinski/so-now-we-know-they-can-blow-up.html, as well as the Wikipedia articles on Lac-Mégantic (the town) and the Lac-Mégantic derailment. 

  

Note added July 18:  Several comments indicate I did not adequately explain the operation of locomotive air brakes.  They are indeed essentially fail-safe in the short term, but not in the long term. 

An analogy can be made to the type of emergency lighting in stores and restaurants that is powered by storage batteries.  Under normal circumstances, the utility power charges the batteries and signals the emergency lights to remain off.  But when the utility power fails, the loss of voltage signals the emergency lights to turn on and operate from their storage batteries.  However, the storage batteries will eventually lose their charge if the power is not restored within a certain time.  When the storage batteries are depleted, the emergency lights will fail as well.

Here is the analogy.  The utility’s electric power is like the locomotive’s air compressor.  The emergency-light storage batteries are like the compressed-air tanks in each rail car.  The emergency lights coming on are like the brakes on each car becoming actuated by the air pressure from the tanks when the pressure from the locomotive fails (either deliberately or accidentally).  The tanks can supply only so much air (which escapes due to leaks, imperfect seals, etc.) and eventually the pressure falls to the point that the brakes no longer hold, just as the emergency lights will eventually go out. 

One reason the brakes are not actuated by a non-pneumatic method (e. g. springs) is that there are situations in which railway workers need cars to roll freely without being connected to a source of air pressure, as when the cars are sorted by being rolled one at a time over a “hump” and down a controlled grade through a sequence of switches.  If the brakes were always applied in the absence of air pressure, this kind of thing would not be possible. 

I hope this clarifies the question of how air brakes on trains work.