Locking in safety: the towerman and his levers are part of history, with relay-controlled systems rapidly joining them, as sophisticated microprocessors take over - Industry Overview

Railway Age, June, 2003 by Tom Judge

Railroads are continuing their rapid transition from relay-controlled interlockings to gain the advantages of systems controlled by high-tech microprocessors. As always, safety and reliability are the key elements. Following are some of the newest technologies from suppliers.

Alstom Transport Information Solutions offers SMARTLOCK, a new family of microprocessor-controlled interlocking systems that are modular in nature to enable customers to upgrade in the future with minimum cost.

Alstom points out that the main benefits of SMARTLOCK are that it is easy to implement and modify, easy to use, easy to interface, has easy fault location, includes preventive diagnostic of field equipment, and all the maintenance facilities are accessible remotely from any point in the system with the required level of integrity through standard PC technology. SMARTLOCK "achieves the highest standards of safety in the railway industry," says Alstom. The system is based on NISAL (Numerically Integrated Safety Assurance Logic) technology.

Alstom provided Canadian National with SMARTWAY conventional signaling products and SMARTLOCK systems for interlocking control, including 100 Control Point in a Box sys reins, 100 GM4000 switch machines, and more than 300 Genrakode units.

Alstom also won several orders from the Indonesian company Jabotabek Railways to modernize the lines that serve Jakarta and its suburbs by supplying a new generation solid-state interlocking system and advanced train supervision systems. This project is part of the construction for a suburban system in an area that serves 12 million people.

GE Transportation System Global Signaling has been in the interlocking business in North America since 1990. The company's core interlocking is the VHLC (originally developed by Harmon), which is the interlocking most in use in North America.

"We have more than 5,000 installations," says Joe Noff-singer, business unit leader for signal products. "We've applied this product in other countries, such as Brazil. We've also introduced it and have safety approval in the United Kingdom."

That same interlocking controller acts as a wayside server for ITCS (Incremental Train Control System) PTC technology installed on Amtrak's Chicago-Detroit line in Michigan. It also serves as the core interlocking on BART, where GETS installed its AATC (Advanced Automatic Train Control) CBTC system. Recently, the company safety-certified its new LED color-light signal module for use specifically with the VHLC interlocking.

GETS released in the first quarter of this year a new product called IWP (Integrated Wayside Platform), which also has interlocking controller capability. This platform can be configured by plugging modules into it to generate track circuits, to key cab signaling, to drive interlocking signals, and to interface to switch controllers. These modules can also be networked together to create larger interlockings using a vital protocol connection. And they can also serve as routers to interconnect VHLC interlockings to create even larger interlockings.

The new IWP platform modules have the same form factor as GETS's Electrocode 5 track circuit product, so Electrocode 5 modules also can be plugged into the IWP.

"The IWP is designed to add many features by plugging in additional modules," Noffsinger notes. "It includes enhanced remote diagnostic capability and will support remote monitoring diagnostics and automated FRA testing."

One of the modules for IWP that will be available later this year is a grade crossing constant warning time system, integrating the functionality of the GETS HXP3 into the IWP platform. It will also support automated testing of grade crossing warning systems when used in that configuration. "This integrated functionality will have advantages to the customer with enhanced functionality, for both installation and the life-cycle cost," Noffsinger says.

Safetran Systems has enhanced its processor-based GEO[R] system for signaling and train control through the use of a "Drag and Drop" application tool. Following the object-based geographic principles that GEO is named for, each component of a signal system (i.e. switch, signal, track circuit) is treated as an individual object with all of the signaling rules and operating behavior associated with that object already incorporated into it. Each signaling object communicates, either via software or an external communications link, with adjacent objects through pre-defined, high-level messages.

This approach provides a tremendous design savings to the customer, says Safetran. With the drag-and-drop approach, an icon in the application tool represents each object. A designer drags the appropriate icons into place on the screen and selects any desired options (i.e. approach times). The application tool automatically creates the link between adjacent objects drawn on the screen. Since all the application logic is already contained within each object, the design time as well as the potential for design error is substantially reduced. For example, the geographic object-based approach automatically considers all possible opposing routes and protects movements against them. The output from the tool is a data file (i.e. a "PROM' equivalent) allowing each GEO hardware module to execute the appropriate application logic. GEO modules can be configured with the necessary hardware to support intermediate locations, end-of-siding locations, and larger interlocking locations.