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Introduced in a
1994 Federal Railroad Administration (FRA) report to Congress titled Railroad Communications and Train Control,
Positive Train Control (PTC) refers to a set of safety objectives that include the
monitor and control of freight and passenger trains in an effort to avoid
collision, control speed and increase rail employee safety. The 2008 Railway
Safety Improvement Act set a U.S. Congressional implementation deadline of 2015
for all US rail providers.
PTC systems
encompass digital data link communication networks, continuous and accurate
positioning systems, on-board computers, maintenance of way equipment, in cab
displays, throttle brake interface, wayside interface units at switches as well
as wayside detectors, including control center computers and displays. Advanced
PTC systems can also encompass interfaces with tactical and strategic traffic
planners as well as work order and locomotive health reporting systems
providing economic impacts including reduced fuel consumption, improved running
time, increased reliability and greater track capacity. On-board equipment
known collectively as the ‘movement authority’ determine a train’s location,
where and at what speed it can safely travel and status of the wayside signal
system communicated by radio to the train.
The train is
continuously monitored by the on-board PTC equipment to determine if an
override of the train engineer’s actions is necessary. PTC can be accessed
remotely, thus eliminating concern over incapacitated crew members. Concerns remain
about eliminating the final decision control currently in the hands of skilled
engineers. While PTC systems claim to have the ability to regulate the speed of
freight trains over 5,000 feet in length and over 10,000 tons, improper speed
control can lead to derailment or other tragedies.
The FRA states,
“Currently, all of the affected railroads are aggressively pursuing development
of the PTC implementation plans required by the Rail Safety Improvement Act (RSIA)
and are adapting their individual PTC systems to maximize interoperability. The
BNSF Railway Company, Union Pacific Railroad, Norfolk Southern Railway, and CSX
Transportation are leading the interoperability effort for technologies based
on the Electronic Train Management System for rail traffic outside of the
Northeast Corridor (NEC). The National Passenger Rail Corporation (Amtrak) is
undertaking similar action for rail traffic in the NEC using the Advanced Civil
Speed Enforcement System.”
Multiple ways
exist to implement PTC systems including track transponders, GPS, centralized
office control and local distributed systems. The problem of interoperability
between systems has come into question and along with the need for a
human/machine interface, effective use of radio frequency remains the biggest
technical challenges faced by PTC.
While PTC
deployment looks to deliver a safer and more efficient American rail network,
it will come at a cost, some estimates place at up to $10 billion US. The PTC
World Congress has been established to meet the 2015 deadline for PTC
deployment and encourages cooperation between the railroad, manufacturers and
suppliers throughout the globe. Railway Age feels, “the North American
signaling market is experiencing something of a calm before the storm.” Feeling
that once interoperability standards are established there will be a market
boom.
Sources:
http://www.ptcworldcongress.com
http://www.fra.dot.gov/rrs/pages/fp_1265.shtml
http://www.fra.dot.gov/pages/784.shtml
http://www.fra.dot.gov/Pages/1804.shtml
http://www.fra.dot.gov/Pages/947.shtml
http://www.metro-magazine.com
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