Case Study

Whittier tunnel

Discover how Frauscher products have helped to modernize the whittier tunnel's signaling system.

Requirement

The Alaska Railroad Corporation (ARRC) decided to modernize the signaling system of the Anton Anderson Memorial tunnel, better known as Whittier Tunnel. At 13,300 feet, this is the second longest highway tunnel and longest combined rail and highway tunnel in North America. About 50,000 vehicles passing the tunnel per month make a reliable monitoring system absolutely vital.

The key point was to replace existing track circuits, which were deemed unreliable having less then optimal availability. Those had to be replaced with a more reliable and robust system, that would not be affected by water logging, moisture, fouled track, dirt crust or other contaminants within the tunnel.

Solution

An evaluation by Burns Engineering, Inc. recommended the use of modern axle counters. The Frauscher Advanced Counter FAdC was chosen. The functionality of the FAdC is to provide a track clear/track occupied indication for the one track section that covers the Whittier Tunnel. This system has a proven track record to provide the expective performance under all weather conditions with highly reduced maintenance work. The FAdC complies with the highest safety standards defined by the SIL 4 requirements.

Whittier tunnel

Application

The project solution is to provide train detection, so that safe signaling may be provided to regulate the two way train traffic and car traffic that is plying over the one single embedded track. The FAdC will interface with the interlocking and energize a relay with its signal. This vital signal emulates the input from the track circuit in all interlocking functionality.

Whittier Tunnel

Products & Tools

Facts & Figures

  • Operator: Alaska Railroad Corporation
  • Scope of supply: Delivery of components, commissioning
  • Scope of project: 1 track section, 2 counting heads
  • Axle counter: FAdC
  • Wheel sensor: RSR180