Alaska Vital Positive Train Control Solution

Overview

Years before the federal PTC mandate, Ansaldo STS USA began the implementation of a Vital Positive Train Control solution for the Alaska Railroad Corporation (ARRC). The solution fully integrates wayside, onboard and office, in a vital capacity, and seamlessly transitions between signaled and dark territory.

Products

VitalNet™ Onboard Computer

VN_Cab_smallThe VitalNet™ Onboard Computer (VitalNet™ Cab) is based on the Ansaldo STS USA MicroCab® platform. It provides positive limit of authority and speed enforcement. This means that any function the system protects will be vitally enforced and stop the train in advance of a target. For example, if a freight train crosses the crest of a hill with a speed restriction on the down side, the profile braking system calculates the maximum authorized speed based upon several determining factors – hill grade, train consist, current speed, speed restriction and braking capacity of the train. The VitalNet Cab then presents the distance to the target and time to penalty at the current speed.

 

MicroLok® II Vital Logic Controller

An Ansaldo STS USA Peer Protocol message is used to communicate the state of MicroLok® II wayside controllers to the VitalNet™ Cab. The Peer Protocol message is sent over non-vital data radio, however the MicroLok II executive developed for the VitalNet Cab supports the Peer Protocol, and when used in combination with the VitalNet Cab and MicroLok II wayside controllers, it ensures the vital communication of information. For example, when a train approaches a signal, the MicroLok II controlling the signal will return the signal’s status to the train’s VitalNet Cab in a Peer Protocol data message, which is transmitted in a vital manner.

 

VitalNet™ Office Safety Server

The VitalNet™ Office Safety Server (VitalNet™ OSS) encodes Mandatory Directives for delivery to the VitalNet Cab and provides a vital computing platform that validates train authorities, speed restrictions, work authorities and dark territory switch positions. The vital protocol was developed to operate with conservative data radio bandwidth requirements. The flexible block design is scalable and allows the system’s configuration to accommodate future changes to the railroad.

 

MicroTrax® Track Circuit and Track Integrity

A broken rail or undetected occupied block can be costly, or potentially hazardous, but leaving a track integrity system running in dark territory can be expensive as well. The MicroTrax® coded track circuit is a low-cost track integrity solution that is used in coordination with the MicroLok® II VitalNet™ CPU. The MicroTrax features efficient power consumption logic and the longest track circuit available (up to 27,000 feet). This means that the units are less expensive to run, and fewer are needed to cover your track, which results in significant cost savings.