Railroad uses IP net to control signals, switches

05.11.2004
Von Matt Hamblen

The Burlington Northern and Santa Fe Railway Co. is nearing the end of the line on the installation of a US$30 million IP network along a heavily traveled rail corridor in the Seattle area, a project that"s expected to increase the reliability of the technology it uses to control signals and track switches. The Sound Transit Telecom project involves the installation of a triple-redundant network of fiber-optic cables and T1 lines that will run for 45 miles between Seattle and Tacoma, Wash., and support combined IP voice, data and video traffic, BNSF officials said during a tour of network sites this week. The installation began two years ago and is due to be completed in 2005.

Fred Gratke, assistant vice president of telecommunications at BNSF, said the IP-based technology is replacing a proprietary wireless radio system that the company has used for decades to relay signal and switch commands between the Seattle tracks and the railway network operations center at its headquarters in Fort Worth, Texas.

The fiber-optic cabling and new network switches and routers are much more reliable than the older system, Gratke said, and the IP-based equipment provides greater network capacity. BNSF is using Ethernet-over-fiber technology that provides 1Gbit/sec. backbone speeds now and is expandable to 10Gbit/sec. throughput.

The IT rollout is part of a $248 million, government-funded initiative that involves adding a third set of tracks as well as expanded signaling and switching capabilities along the Seattle-Tacoma rail corridor, which is used by freight, commuter and interstate passenger trains. BNSF planned the new network, is managing the installation and will maintain the technology. But the bills are being paid by Sound Transit, a regional transportation agency.

"The third track adds more signals and more monitoring points, which presented a lot more points of telemetry along the track," Gratke said. The increased information flow would normally overload BNSF"s wireless channel, but the railroad expects to have "nearly infinite capacity with the fiber," he said.

Nick Marquard, project manager for research and technology at Sound Transit, said the IP network will eventually be expanded to support data transmissions for electronic signs at commuter rail stations as well as IP video surveillance cameras.

As of this week, BNSF had installed 32 trackside "bungalows" that house the new networking equipment; 50 bungalows are planned along the 45-mile route. The buildings contain switches from Nortel Networks Corp., voice-over-IP phones from NEC Corp. and products from several other vendors. Central offices in Seattle, Tacoma and Auburn, Wash., are also on the network, Smith said.

The transition has been a smooth one for BNSF"s signaling organization, said James Abbey, the company"s manager of railroad signals for the state of Washington. "At the start, everybody in signaling was reluctant to try IP, since it was the first of its kind," Abbey said. But the new network has thus far been reliable, with no delays to trains.

In addition to its greater reliability, the fiber-based network is more secure than the wireless radio system, said Greg Britz, manager of telecom engineering at BNSF.

Britz said the fiber infrastructure was made triple-redundant in the event of a major train derailment that could both knock out a bungalow and dig up the ground near the tracks deep enough to sever a backup fiber link. If that happened, vital information could still be sent via T1 links between each central office and the remaining fiber lines, he said.