AUSZUG | eb - Elektrische Bahnen INT 2/2015

60 113 (2015) INT 2 Contact Lines cludes the low-cost Sicat 8WL5078 tension wheel assembly (Figure  2) for up to 24 kN. The four-spoke tension wheel of the Sicat 8WL5000 series up to 30 kN (Figure  3) was subsequently converted to the greaseless bearing version. Today, these ten- sion wheel assemblies are used in the German Rail network under the names Ebs 08.02.02, Ebs 08.04.02 and Ebs 08.06.02. 2 Requirements 2.1 System and environment-related requirements Tensioning devices with wheel assemblies and weight sets fulfill the requirements of EN 50119 [1] and EN 50125-2 [2] as well as the following applica- tion-related requirements: • Usability for all current overhead contact line systems • Suitability for ambient temperatures between –40 and +50 °C • Compensation of variations in length due to Joule heat, to creep of contact and catenary wires and to contact line wear • Arrangement of weights outside publicly accessible areas or use of drop protection devices for personal safety • Easy installation requiring little effort • No or at least low maintenance • Low lifecycle costs, for example due to maintenance-free bearings and corrosion- resistant materials • High availability and operational security It is possible to install the tension wheel devices in overhead contact lines in different ways. Fastenings on poles or structures, horizontally or vertically offset arrangements and arrangements integrated in poles are standard nowadays. Locking or blocking facilities are required to avoid consequential damage as far as possible in the event of a wire break, for example due to distortion of the catenary system and damage to components. Wire breaks as such are rare and mostly caused by external influences such as falling Figure 2: Sicat8WL5078 tension wheel assembly with mechanical transmission ratio of 1:3 up to 24kN operating load, with integrated weight stack in a H-type pole and installed Sicat CMS contact line monitoring system in the network of the mass transit authority Hallesche Verkehrs-AG. Figure 3: Tension wheel assembly with a mechanical transmission ratio of 1:3 and 30kN operating load, Sicat8WL5000 on DB’s new high-speed line between Leipzig and Erfurt.