Project Overview Union Switch & Signal Inc. was awarded in June 2004 a contract to deploy
the next generation dispatch and Vital Positive Train Control (VPTC) for
signaled and dark territory for the
Alaska Railroad Corporation (ARRC),
in the USA.
The contract has a two-phase approach in which US&S will provide a
complete VPTC system, including US&S’s latest Computer-Aided Dispatching
(CAD) system, vital Office Safety Server (OSS), and vital Onboard Computer
(OBC).
The project will be the first vital dark territory implementation of
positive train control in the industry.
During Phase 1, US&S provided a VPTC-ready CAD system, including
non-vital GPS train tracking. Upon completion of Phase 2, ARRC will have a
complete VPTC system. ARRC’s data radio network, supplied by Meteor
Communications Corp.® (MCC), will provide railroad-wide VHF packet data radio
coverage and DGPS corrected position information to the system.
The VPTC system objectives are:
• Prevention of train-to-train collisions
• Enforcement of both temporary slow orders and permanent speed
restrictions
• Protection for roadway workers and their equipment
operating under specific authority
Mandatory Directives (MDs), including authorities and bulletins, are sent
from the office to the OBC via a vital communication protocol. The VPTC system
is designed to operate in dark or CTC territory, with the ability to make a
seamless transition from one territory type to the other without any impact on
operations. Additionally, it interfaces with a variety of devices, including
signals in centralized traffic control, manually monitored switches and track
integrity systems in direct traffic control, and wayside defect detectors.
The vital communications protocol and vital OSS and OBC subsystems allow for
digital transmissions without requiring the traditional read back associated
with MDs. The soft-key based Locomotive Display Unit (LDU) displays
context-appropriate information to enable the train crew to operate efficiently
and safely with less verbal communication. The MDs’ rules and the state of
wayside devices are factored into speed and movement authority profiles in the
OBC to provide a speed profile to the next target. The system is expandable,
allowing for an interface with US&S’s Optimizing Traffic
PlannerTM and CAD Enterprise ServicesTM products.
VPTC Product Details
The system is based on the US&S next generation CAD product. The basic
product includes security, traffic control, train sheets, authorities,
bulletins, priority-based planning, and reports. ARRC-specific features include
an advanced direct traffic control authority subsystem, PIN-based protection
for work authorities, support for MCC’s hy-rail limits compliance system, and
an interactive train graph for planning. The CAD system is scheduled to be
deployed at a number of Class 1 railroads. The system is scalable from one to
hundreds of users, with a large number of redundancy and disaster recovery
options.
The vital OSS is based on the US&S MicroLok® II platform, providing an
industry-leading vital computing platform for validation of train authorities,
speed restrictions, work authorities, dark territory switch positions, and
encoding of MDs for delivery. The vital protocol has been developed to operate
with conservative data radio bandwidth requirements. Flexibility in block
design, with the ability for the customer to change the system’s configuration,
provides the customer with the ability to grow and change the railroad in the
future.
The vital OBC is based on the US&S MicroCab® platform, which provides
positive limit of authority and speed enforcement. This means that any function
that is protected by the system will be enforced vitally, stopping the train in
advance of the target. For example,
if a freight train is crossing the crest
of a hill with a speed restriction on the down side, the profile braking system
will calculate the maximum authorized speed based upon the grade on which the
train is operating, the consistency of the train, the current speed, the speed
restriction, and the braking capacity of the train. The OBC also presents
the distance to the target and the time to penalty at the current speed. The
OBC system will always vitally enforce the protection function, regardless of
the non-vital operation of the LDU. The LDU allows access to a large number of
important, but non-safety-related functions. Options for redundant data radios
and WiFi event log uploads are available.
US&S provides world-class customer support 24/7/365. Our customer
support engineers are on call to answer customer support questions and recover
system disturbances. US&S’s commitment is to employ the necessary resources
to support each product in order to meet rigorous railroad operational
demands.
