According to the FRA, “A theme cutting across virtually all the RD&D program elements is the use of sensors, computers and digital communications to collect, process and disseminate information to improve the safety, security and operational effectiveness of railroads.” The FRA also advocates taking an integrated approach to implementing intelligent transportation systems (ITS) to allow the benefits of those technologies to compound.
That includes development of systems incorporating new sensor, computer and wireless communications technologies into functions for train control, braking systems, grade crossings, and even planning and scheduling systems. Such advanced train control systems are intended to prevent switching mistakes, control excessive speed and automatically enforce fail-safe control in the event of human error. They also hold promise for more efficient rail system density by allowing a higher concentration of rail equipment to operate safely within a given track infrastructure.
Fortunately, a variety of European rail applications and standards that affect safety, capacity, economy and even customer satisfaction have already proven many aspects of those technologies in specific executions.
In recent years, both government and industry in Western Europe have looked to improve on interoperability that could accommodate greater equipment densities in shorter intervals on existing railway networks, reducing barriers to timely and efficient commerce and travel. This can be especially important in applications where freight and passenger service might share the same rail infrastructure.
One such initiative is the European Rail Traffic Management System (ERTMS) that holds promise for easing such bottlenecks. It is designed to be a significant improvement over the current patchwork of more than 20 national standards. Members of UNIFE (The Association Of The European Rail Industry), in cooperation with the EU and railway stakeholders, are helping to develop the project. Participants include Alstom Transport, Ansaldo STS, AZD Praha, Bombardier Transportation, Invensys Rail, Mermec Group, Siemens Mobility and Thales. This effort to establish a common standard is being recognized not only in Europe but also by a number of other international countries as a new de facto global signaling standard.
Another important complement in standardization is the European Train Control System (ETCS). It uses a GSM-R (Global System for Mobile Communications — Railway) radio system as a method of providing voice and data communications between the track and train. GSM-R builds on proven GSM technology and standards with its own frequency band dedicated for specific and advanced railway functions. This is a very important consideration as one of the main objectives was to employ a system already proven in use and where off-the-shelf products were available with a minimum of modifications.
Other embedded technology control systems also offer benefits for a cross section of applications, from the ground up, regardless of rail format — high-speed passenger service or metropolitan commuter systems:
Maintenance Control — Computer-aided tamping systems help to calculate and visualize track geometry as well as control the subsequent track-laying process itself. For high-speed rail systems, allowable deviations of the track geometry are limited to a few millimeters in all three dimensions. The same systems can monitor track geometry during initial installation as well as subsequent periodic maintenance drives. Automatic ballasting and tamping operations call for extremely rugged electronic equipment to maintain precision despite the heavy shock and vibration experienced during track maintenance.
Tilt Control — Tilt-control technology uses sensor-controlled actuators to adjust the railcar body in relation to the “bogie” or wheel truck on which it rides, depending on the centrifugal forces encountered. This allows safer operation and greater passenger comfort in turns, with fewer compromises in high-speed performance. Efficient bogie control also leads to lower energy consumption.
Automated Train Protection — Positive train control (PTC) is a communication-based system that uses GPS capabilities for position assessment and radio frequency data links for communication with dispatch offices, grade crossings and railway workers along the right of way. To satisfy the three basic safety characteristics specified by the FRA’s Railroad Safety Advisory Committee (RSAC) PTC Working Group, a PTC system must: