Emissions Testing; another reason to doubt the reports

A few weeks ago, I wrote about one of several buses that emitted clouds of smoke from places other than the tailpipe.  I noted observations about one particular bus and recalled that it was not an isolated occurrence.

In an interesting twist, at a recent MBTA Rider Oversight Committee meeting (which are open to the public), Eugene Benson of TRU-ACE gave a presentation in which he mentioned that the T has published the results of an emissions monitoring program online.  The test results themselves are stale and the most recent is from January 2009.  (Halfway is better than not-at-all, I guess.)  In addition, Eugene didn’t mention it, but in an unexpected twist, the diesel buses rarely fail their tests!  Sparkly clean!  Ten MBTA buses required repairs in the most recent six-month report, and only one diesel bus (#293) made the list.  Only the clean-fuel CNG buses required remedial work.  If you believe the reports, I suppose you might conclude that the clean-fuel buses are nastier than the diesels.  Who would have guessed?!?

But can you believe the reports?  Remember, the reports presumably were generated by the same MBTA mechanical supervisors that recently were dismissed for allegedly fudging their record-keeping.

MBTA emissions testing apparatus that fails to detect emissions from undercarriage  (click to see report)

Well, here’s another reason to doubt.  The MBTA included a diagram in its robust report explaining the emissions methodology.  The report explained that the T uses an elaborate visual detection system that scans the tailpipe on the roof of the bus.  When the emissions come out the tailpipe, the computer analyzes what is left and gives a result.  What happens when emissions come from the undercarriage and not the tailpipe?  Those emissions, dear reader, do not exist.  Poof!

Even the most credulous among us would have to admit that the detection system that is depicted will not determine whether the exhaust system on a bus is compromised and leaking.  And if the exhaust is leaking then the bus will not be flagged as having an emissions problem.  Wow.  That has to be a flaw that even an overworked, ethically flexible MBTA maintenance manager could appreciate.

It’s a leap to wonder whether, at the same time that T maintenance supervisors were revising mileage logs to avoid required servicing, were they also circumventing the emissions testing program by … simply allowing leaking exhaust systems to keep on leaking?  Discuss among yourselves.

Bus Exhaust Other Than From Tailpipe

Tailpipe up top, but the exhaust escapes below.

Tailpipe up high, but the exhaust leaks out below

Recently, I saw bus 0462 (marked in the picture for route 504) belching fumes.  That itself is not remarkable.  Some buses just stink.  But this bus stunk in a peculiar way.  See in the picture to the right how there is an exhaust pipe up high to the left of the bus, strategically above the passenger compartment and away from the curb?  That is where one would expect the bus fumes to escape.

Instead, the fumes on this bus came out the bottom, apparently whenever the driver hit the gas, in a big gray plume.  (The picture shows the bus idling).

I’ve seen several buses like this in the last year.  Exhaust pipe on the top, heavy stinky exhaust cloud down below.  When I’ve been unlucky, I’ve ridden on that bus and been made queasy by diesel fumes that perfumed the passenger compartment.  Maybe it was the same 0462 bus over and over.

If the cloud of exhaust underneath the bus is indicative of a major leak in the exhaust system — the other possibility of a dummy exhaust pipe seems unlikely — one might wonder how the bus ever made it out of the shop.  Ahem … make that “might have wondered,” i.e., wondered in the past.  Turns out the bus maintenance people have been falsifying records to keep up the appearance that they could handle their backlogs of work.  So far nineteen supervisors have been disciplined for faking regular maintenance of the buses.

Here’s guessing 0462 is overdue for its next checkup.  Hopefully the T will have enough supervisors to deal with this problem soon.