advertisement

---

Alaska Railroad Corp. (ARRC) recently awarded a contract to Union Switch & Signal Inc. (US&S) to provide a positive train control (PTC) system — the first vital stand-alone PTC system to be put into service, according to a prepared statement.

The system will be designed to prevent train-to-train collisions, enforce speed restrictions — including permanent restrictions and temporary slow orders — and protect roadway workers and equipment operating under specific authority.

US&S will provide a computer-aided dispatching system, safety server using the supplier's MicroLok II vital logic controller and an on-board computer based on the MicroCab platform. ARRC plans to commission the system in first-quarter 2007.

"This project is very significant because it sets a new standard for safety in the industry," said Eileen Riley, ARRC vice president of projects, engineering, technology and signals.

Operating a predominantly unsignaled network, ARRC determines train location via on-board Global Positioning System receivers. In unsignaled territory, trains will be dispatched via direct traffic control (DTC) authorities that will be digitally transmitted to a locomotive via a data radio network. US&S' MicroLok safety server will be designed to validate DTC authorities before they're issued.

"Other PTC systems that have been implemented to date have been overlayed on existing signaling systems," said US&S President and Chief Executive Officer Ken Burk.