Delivering Railway Signaling over Fiber

TCDD (Türkiye Cumhuriyeti Devlet Demiryolları), the Turkish state railway, had long employed a signaling system between Ankara, the country’s capital and second-largest city, and Kayseri, a large industrialized hub in central Anatolia, located about 325 kilometers (200 miles) away.

Until now, the signaling along the route was transported with catenary copper lines, resulting in transmission quality issues due to the noise generated by high voltage. The railway was determined to replace the entire system along the most heavily traveled section of the route and transport the signaling between the cities over alternative fiber optic infrastructure. The challenge was that the access infrastructure between the control rooms and the two stations on either end would continue to be copper.

After consulting with RAD’s local partner, Dengebir Telekomunikasyon, TCDD chose RAD’s Megaplex multiservice networking platform to enable the migration. Megaplex units were deployed in the stations starting with Ankara Central and ending at Kayseri Central. The copper lines between them were likewise replaced with fiber. The copper lines that lead into the first station and lead out of the last, however, remain in place.

The Megaplex, part of RAD’s Service Assured Networking (SAN) portfolio for transportation systems, grooms, aggregates and transports multiple broadband and narrowband data and voice services over copper and fiber, as well as DSL, wireless, or satellite circuits – all in a single-box. It is especially suitable, therefore, for use as economical, compact remote multiservice nodes for transportation systems.