ALASKA Railroad has awarded a $4·8m contract to Union Switch & Signal for installation of Positive Train Control on its 846 km network, for commissioning in the first quarter of 2007.

PTC is intended to prevent collisions, enforce permanent and temporary speed restrictions and provide compulsory protection for track maintenance staff operating under specific authority. The vital technology will keep trains a safe distance apart, and will be able to apply the brakes on locomotives if drivers ignore slow orders. This will allow dispatchers in Anchorage to control trains anywhere on the 756 km main line between Seward and Fairbanks.

According to US&S President & CEO Ken Burk, the ARR project will be the first vital stand-alone PTC installation to be put into service. The contract includes a computer-aided dispatching system, a safety server using a MicroLok II vital logic controller and on-board computers for each train based on the company’s MicroCab platform.

At present 85% of the ARR network is unsignalled, with satellite train location using on-board Global Positioning System receivers. In dark territory, trains will be signalled using direct traffic control authorities transmitted to locomotives via a digital radio data network.