Orange Line uses same company's hardware as DC Metro
That slowdown on the orange line and the delays due to manual control ? ... maybe headed off a bad accident.
My notes on all this:
- hey Joe Pesaturo, a failure is not "isolated" when it's a signaling system for a railway track. The track itself may be "isolated" and it's also "stationary". Trains come TO IT. That's the point. If only one board failed in a configuration (like DC's) where apparently (my interpretation of the article) a single segment failure out of thousands can allow a crash... that must be considered a systemwide failure, not an isolated failure. Apparently the MBTA can, and did, detect and respond to the sensor failure, and thank God for that.
- as a software and process designer, I interpret the Post article to indicate that if a segment of track cannot "see" a train on it, the the DC system thinks there is no train on that segment. But sensor failures are commonplace in the real world. That, we should anticipate in building software that takes input from sensors and makes life-critical decisions. Shocking to me: that software would not have noticed the disappearance of a train as it moves from segment A to B, from B to C, from C to.. oh, it's gone. OK track's all clear.
Is that really how this stuff is designed? Did the MBTA get something right, and DC blow it?
From the Washington Post:
Meanwhile, a top official at Boston's transit system called Metro the night of the crash to discuss the signal system, according to Massachusetts Bay Transportation Authority spokesman Joe Pesaturo. He declined to say what was discussed.
Boston uses an automated train protection system similar to Metro's.
Last month, the MBTA experienced what Pesaturo described as an "isolated" signal system failure when a faulty circuit board along the track in one section of Boston's Orange Line failed to detect trains. Engineers discovered the problem and immediately stopped using the automated system while they checked all circuit boards. Trains had to be dispatched by radio for 12 days, and MBTA personnel were posted at each station to give the go-ahead for trains to proceed. That caused delays.
Boston uses signal systems made by the same manufacturer as Metro's, Alstom Transport. No problems were found with the other circuit boards, and the faulty one was replaced by the manufacturer, Adco Circuit, a subcontractor of Alstom's, Pesaturo said.
the full story: http://www.washingtonpost.com/wp-dyn/content/article/2009/06/24/AR2009062400815_pf.html
and attorneys are standing by! http://www.bostoninjurylawyerblog.com/2009/06/boston_mbta_accident_attorneys.html
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A to B to C to all gone!
I've never done embedded or safety-critical systems, but I have a vague sense that tracking that kind of second-order information was much less common 10-20 years ago. We take it for granted now; if my photos have GPS coordinates and timestamps, of course iPhoto can show me a map of my route - it's trivial.
But in the days before search, fast networks and large memories, I suspect that'd be one of those "sanity checks; disable for production" features. As late as 1998, I had a massively parallel distributed database where we wanted to rate-limit inserts - but the cost of tracking all that state information was far greater than the savings from rate limiting.
But these routes are fixed in place
They're tracks that don't really move much
granted, some tracks are offline at times making for wonky routings, but they're already going to manual operations during those periods, like when North/South trains share a track segment
On that stretch in DC, there's one set of tracks on the left, one on the right...
Honestly, if you're going to do a life-critical automation system without basic sanity checking, then, well, don't do the automation system.
The whole point of that system is to prevent collisions by running trains right up to the brink of capacity (60mph authorized/commanded speed, and a presumption that the track is clear).
How can this be guaranteed without minimal state tracking? When the T wouldn't give me access to live data a few years ago for a project, I created a simulator to run make believe trains around a make believe subway system. it really wasn't that awful.
At the minimum, exceptions due to weirdness could at least call out for operator intervention before proceeding...
I think one massively bad route chosen by many systems developers is to automate too far... knowing there is an exception is plenty, if you carefully choose what constitutes an exception and design the human processes to follow up on it well..
I hope I'm wrong and that the Post and Globe stories are just inaccurate, but if not, this is unforgivable.
Real-world note: traffic signals systems (are supposed to) have lockout circuits that prevent "all green"...
when these are interposed in signaling, it's possible THEY could fail, but if designed in a fail-safe fashion, the only outcome of a monitor failure should be fallback to a safer state, either flashing or all-red... thus at times we see traffic signals flashing rather than working in the usual manner...
Good point
I was thinking of much larger systems, where such "state tracking" would have to be an abstract operation. You're right - for a small transit system, that's the kind of thing that could be hand-coded for each route.
Homer voice
"I like stories."
Officials say crash like D.C. Metro not likely in other cities
Another perspective...
"But public transit officials say a crash like the one in Washington is unlikely to happen in other cities that rely on a similar automated system, including Philadelphia, Pennsylvania; San Francisco, California; Boston, Massachusetts; Miami, Florida; and Atlanta, Georgia."
http://www.cnn.com/2009/TECH/06/25/automatic.system.washington.crash/index.html
Officials say...
That's nice to hear but I'd really like to know their rationale before feeling good about it.
I think that if you asked officials in DC (who had ignored toothless mandates to change much of what they were doing), they would have also said, last week, that a crash was unlikely!
I mean, really, what public transit system in the US would operate (admittedly) knowing that a crash was "likely" ??
Question for logicians: is "not likely" in this usage the complement of "likely" ?
And are they talking about the accordion-folding due to the car construction, or the vulnerability to single-sensor failure?
If it's sensor failure, I still maintain that Boston's recent urgent switch to manual operation for 12 days on the Orange Line suggests that single-sensor failure in Boston does create high risk on the tracks and they know it.
DC Metro
Kind of off topic, but I was taking the DC Metro one morning when I was down there, and had a cup of coffee with me. This woman looks at me and kind of rudely tells me that no food or drinks are allowed on the trains.
I gave her a dirty look and finished my coffee anyway, but the trains were spotless and clean.
Someone told me that Gorbachev came to the US once and commented on how dirty the trains were. Then Regan or someone ordered the trains cleaned up and added the new rule about no food or drinks on the trains anymore. I dont know how true that story is but it sounded kind of funny.
That is funny
But some of the subway stations in ex-Soviet countries look like they have Boston outclassed:
http://images.google.com/images?q=russian%20subway%20station
http://images.google.com/images?q=russian%20underground%20station
http://beeflowers.com/Metro/
The best that can be said about most MBTA Red Line stations is that they're ugly, somewhat dirty, and utilitarian. Well, utilitarian when the service is working reliably. For example, even the station in picturesque Harvard Square looks like a dim parking garage. Other popular MBTA motifs include loading dock, prison, and 19th century boiler room.
Soviet subways
My uncle went to Russia a bunch of times during Soviet times in the 1980s and said the subways there were spotless.
Must have been the threat of big brother....
In some ways...
...over the last few decades (especially the last one), the US has moved closer to the evils of the Soviets. Like we'd secretly *lost* the Cold War, and were selectively instituting their "best practices."
Sadly, despite the trend in the direction of totalitarianism, our trains still don't run on time. :)
No junk food
A friend who travelled the Soviet Union told me that their public areas were clean because they didn't have any junk food for people to drop wrappers from, and no newspapers or magazines to speak of, either.
Think about the junk you see around on a daily basis, and that makes some sense.
Who was breaking the rules?
"I gave her a dirty look and finished my coffee anyway"
And she was the rude one???
Classic Example
If there is one behavior that characterizes a masshole, it is the dual belief that: 1) the rules do not apply to ME; and 2)anybody who points out that one is breaking the rules is the wrong and bad person worthy of rudeness and derision.
I was totally gobsmacked how many massholes in comments about Manny being Manny in Seattle expressed the amusingly "stuck in high school and can't get out" belief that ignoring basic laws and rules makes one an adult somehow - it isn't about your civic duty to public safety, it's about privilege over those people over there.
The Metro cops actually do put people in jail for eating, without any warning or chance to just throw stuff out. It would have been interesting if one went after Pete and got a rude stare. Would he have defended himself or the cops?
Would he have defended himself or the cops?
The biggest dilemma of his life.
People actually get put in jail in D.C.
For doing what you did.
http://www.washingtonpost.com/wp-dyn/articles/A22456-2004Jul28.html
http://www.rutherford.org/articles_db/press_release.asp?article_id=453
Gimme a break...
If I lived in DC and was on the train, knew the rules, and saw someone sipping a cup of starbucks on the train, I might get their attention, and say something like "excuse me sir/mam, just to let you know that food and drinks aren't allowed on the trains here in DC" and I would have smiled while I said it in a friendly tone of voice.
This woman gave me a dirty look, and in a condesending tone snapped at me that there was no coffee allowed on the train in a very rude way.
There was nothing I could have done with the coffee anyway, I never saw a sign, never knew the rule, and would have never littered either way..
So swirrly, I didnt know THE RULES, and the person that pointed it out to me WAS RUDE. As a cop I would have never talked to someone the way this lady spoke to me.
And if it were a cop that spoke to me that way, I would have given them the same dirty look. (except I wouldn't continue to drink the coffee). I wouldnt have made any sarcastic comment like the woman that got arrested did either.
But thats one of the dumbest criminal process I think I have ever heard of. An arrestable offense that is only a $10 fine?
Simply doesn't make sense to me if thats true. Would be a much more productive law if it were a max fine of like $500 or something so it would at lease cover the extra cost of processin a prisioner and what not.
You should have known the rules
The no food or drink laws are prominently posted throughout the Metro system in DC. All you had to do is read - and understand that you were included.
Read Michael's links. It would be fun for you to get bagged for chewing by a cop. You like to defend everything that cops do - I wonder if that would apply to such arbitrary police action in your direction?
Again, gimme a break.
I didn't know the rules. Im a tourist. I never saw any sign, and I am going to bet thousands of other tourist around DC also dont see those signs.
How many arrests in the last 40 years do you think the DC police have had for this kind of stuff? Probably the same amount of jaywalking arrests that MA police have. It happens, but only to those that willfully disobey the law.
I dont defend everything cops do, but it is a job that doesnt have black or white answers like everyone loves to think it does. And I have to defend many things that people have no clue about. Its also a job (like many others) where if you never actually do it, its hard to come on here with know-it-all answers from law.com websites that many people love to cite.
These arrests got lots of press attention
These arrests got national coverage. I remember hearing about them -- and being rather appalled. I have no idea what kind of signs are posted (as I haven't ridden on the DC system for at least 13 or 14 years).
Oh yea I bet they did...
Thats why you don't see cops in MA give out jaywalking tickets. Because people in MA love to play the 4th amendment game with the old "you have no right to stop me, and I dont have to identify myself" game. So cops could arrest jaywalkers, but police departments (and cities) have come to the conclusion that they are better off not enforcing these laws for that very reason, they dont want the press attention or news articles of "cops arrests 75 year old woman crossing the street"....well the chiefs and mayors dont want that stuff anyway.
Plus the girl eating the french fry one did seem pretty excessive, and Im sure there was more to the story.
But like any small law (jaywalking, playing music at night, picking up trash at 4am, mowing the lawn at 2am,) when court hearings for small fines ($1 jaywalking in MA, and $35 for a lot of small ordinances) then arrest is the only way to stop these willfull and intentional disregard for these laws.
I did neither when I had my coffee in DC, and thats the big difference.
But like I said, thats one problem I had with that law, $10 isn't enough to make it worth while to enforce.
I read the Post every day
If there was more to the story, it never got written about... and there were certainly plenty of follow-up articles. The cop DID arrest her just for the French fries (and for disrespecting his authoritah, natch) and that's why there was an outcry. The story IS that zero-tolerance is dumb.
yea I meant it the other way too though..
Like some cops go to the letter of the law no matter what they do. This cop could have been one of those and might be at a desk since the incident. Laws like this in MA are only arrestible if you willfully disobey them over and over or dont identify your self to the officer.
It is an interesting subject though. Many crimes here in MA are treated in many different ways. Public drinking is one of those. You can be arrested, summonsed, put in for a probable cause hearing, issued a city fine, issued a city warning, or given a verbal warning! Thats 6 legit enforcement options for law enforcement for many of these types of crimes.
You hope the cop has enough common sense to do the right thing in each situation.
Something else to ponder
Washington Metro management replaced their system-wide Alstom 70 year lifespan signal equipment because it was showing signs of failure after being in service for about 24 years.
MBTA management replaced their Orange Line Alstom 70 year life span signal equipment because it was showing signs of failure after being in service for less than two years.
Makes you wonder which transit system REALLY has the better construction standards and management.