There's a proverb
of uncertain origin that begins, "For want of a nail, the shoe was lost,
for want of a shoe the horse was lost; and for want of a horse the rider was
lost; being overtaken and slain by the enemy, all for want of care about a
horse-shoe nail." That
particular version is attributed to Benjamin Franklin, but all the various
versions make the same point: lack
of attention to apparently minor details can sometimes have major
consequences. As more information
emerges about the tragic AMTRAK train derailment in Philadelphia on May 12, it
looks like what began as a minor kerfuffle over frequency allocations may well
have kept a new train-control system from preventing the deaths of eight
passengers and the injuries of many more.
At this writing,
no one seems to know for sure why the Northeast Regional train heading from
Washington, DC to New York City sped up to 106 MPH (169 km/hr) as it entered a
curve near a rail intersection called Frankford Junction. The maximum recommended speed for the
curve was 50 MPH (80 km/hr). All
the train's cars left the track, killing eight passengers and injuring at least
200 others. There were some
reports that an object might have hit the train's cab in the minutes before the
wreck, but presently the reason for the train's excessive speed is not definitely
known. At the time of the wreck,
the train was under the manual control of engineer Brandon Bostian, who was
apparently knocked temporarily unconscious in the crash and claims to have no
memory of the moments immediately before the derailment.
In many parts of
the U. S. including the Northeast, railroads have installed an automatic system
called Positive Train Control (PTC) that could well have prevented the May 12
tragedy. A fully operational PTC
system continuously monitors a train's position by means of radio links to
trackside transmitters, and calculates the maximum speed that is allowed at
each point along the route. If the
system notes that the train is going too fast, it will automatically apply the
brakes to reduce speed.
Why wasn't the
Northeast Regional using PTC in Philadelphia? Because AMTRAK hasn't been able to purchase a 220-MHz
radio-frequency allocation (channel, essentially) to put it into operation there
yet. And thereby hangs a rather
tortuous bureaucratic tale.
On their own over
the past decade or more, railroads have developed pieces of what amounts to PTC
using various existing equipment, and the most popular type of train-control
radio systems use the 220-MHz frequency band. For most of its existence since the 1930s, the U. S. Federal
Communications Commission (FCC) allocated the limited resource called the
radio-frequency spectrum through a purely administrative process, and in
principle at least, money had nothing to do with it. In practice, political pull and other arbitrary factors
influenced the FCC's decisions. Partly
in response to accusations of unfairness, in 1994 the FCC began auctioning
spectrum slots to the highest bidder, and most observers say that auctions have
led to a fairer and more efficient set of allocations. But in the case of the railroad's need
for 220-MHz slots for its PTC system, the market method of frequency
allocations may have failed.
The legal
requirement for railroads to use PTC originated with a Congressional mandate
passed in 2008 mainly to improve safety.
In that legislation, Congress told the railroads to finish the job by
December of 2015. Most railroads
have largely complied by now, despite problems with interoperability of
different systems developed by different lines and the fact that one railroad may
operate on tracks owned by several other railroads. When PTC was passed into law, the most common frequency band
used for these types of train control and monitoring operations was 220 MHz, so
the railroads decided to use their existing 220-MHz hardware and to require all
PTC equipment to use that band. If
more bands were used, a single train might have to carry equipment that works
with three different bands, for example, and as PTC was already costing billions
of dollars to implement, they stuck with 220 MHz.
That was fine for
most areas, but the railroads ran into a snag in some regions, including
Philadelphia. There the 220-MHz
slots were either not available, or were priced at a prohibitive level. The railroads asked the FCC simply to allocate
the needed frequencies for free, so that they could meet the
Congressionally-mandated deadline, but the FCC essentially said tough beans, go
buy them like everybody else does.
And Congress did not fund the costs associated with the PTC mandate, so
the rail lines have been doing it on their own dime. So at the time of the Philadelphia crash, PTC was not
working, but not because of any hardware problems. The bureaucracy had simply not done its job yet.
PTC is not a
flawless system, and it is not absolutely certain that it could have prevented
the Philadelphia crash even if it had been working at the time. Putting on the brakes for a train is
not as simple as jamming your foot on the brakes of your car. A friend of mine is a locomotive
engineer on an excursion train that operates near Austin. He has explained to me how the brakes
on each car have to be applied at a certain carefully judged rate, and sometimes
even in a certain order, so that the train doesn't undergo stresses that can
cause severe shocks or even break couplings and separate the cars. Even just locking the brakes so the
train skids along the track can severely damage the wheels, necessitating
extensive repairs. But sometimes
it's necessary in an emergency.
We will never
know whether PTC could have prevented the Philadelphia train wreck. But excessive-speed wrecks are exactly
the sort of thing that PTC was designed to prevent. While making everybody pay for frequency allocations seems
to be the fairest way to do things in most cases, the FCC ought to consider
making exceptions in situations involving serious safety issues. Sometimes the old ways are better, and
allowing for emergency no-fee allocations in situations where an organization
is caught between an FCC rock and a congressional hard place seems like a good
idea. But it won't bring back
those who are no longer with us because of what happened in Philadelphia.
Sources: I referred to news articles
on Brandon Bostian at http://www.cbsnews.com/news/amtrak-crash-brandon-bostian-cellphone/,
a list of fatalities in the wreck at http://6abc.com/news/name-released-of-8th-victim-in-deadly-amtrak-crash/719973/,
and the Wikipedia articles "2015 Philadelphia train derailment,"
"Positive Train Control," and "For Want of a Nail."
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