Elektrizace železnic Praha refurbishes the overhead contact system in Estonia

1. 2. 2012

November 2011 saw the beginning of the first excavation work; the project is in full swing now. On 29 January 2012, the first completed section, Klooga – Klooga-Rand, was put into operation. The difficult conditions for laying foundations in quicksand have caused a one-month delay in the laying of foundations and erecting masts, but the overhead contact system has been installed on schedule – during three five-hour closures and nine days of a continuous service closure.

The purpose of this retrofit is to replace the oldest and most worn out sections of the existing overhead contact system. The total length of the railway track being refitted is 65 km (47% of Estonian electrified railway network), of which 20 km is double track. During construction, approximately 1,600 precast foundation slabs and anchorage blocks will be laid, and some 1,200 DSE masts, 60 BP masts and 40 TBS masts will be erected. Despite the owner’s initial mistrust in the reliability of a dc overhead contact system with a single contact wire, agreement was finalised on the standard J system (150 mm2 Cu / 15 kN + 120 mm2 Cu / 15 kN), which may be extended to include one or two 120 mm2 Cu reinforcing wires, depending on the energy calculations. Estonian railways have one special feature: 10 kV three-phase lines supplying all railway loads are hanged on the masts of the overhead contact system. It will therefore be necessary to deliver and install more than 800 mast arms with HV insulator sets. In addition, cables or even bare conductors of 220V/380V lines, which supply the signalling equipment and lighting systems (some 200 new mast arms) and metallic and optical fibre communication cables (some 800 new mast arms), and also lighting fixtures (some 50 units), will be fastened onto the new OCS masts. The contract also includes the preparation of the designs and specifications for the project.

This project is a major challenge for Elektrizace železnic Praha, heralding additional contracts in Estonia and the whole Baltic region.