The objective is to rebuild the existing 45 km long diesel-operated railway of Metro Mondego, Portugal, into an attractive, efficient and modern city/suburban railway. FERBRITAS, the engineering and planning department of the infrastructure manager, appointed ENOTRAC as power supply specialists. The scope covers 3 aspects as follows:
ENOTRAC conducted a concept and system study to identify the best electrification scheme for Metro Mondego. Using technical criteria, performance indicators, capital costs and running costs, the study evaluated and compared several options. The study considered 750 V DC for the inner city area. For the outer sections, electrification with 750 V, 1500 V, 3000 V DC, 25 kV 50 Hz, or diesel traction was considered. The simulations with FABEL, ENOTRAC’s rail system simulator, formed an important technical basis for comparing the various scheme options. As a result, an optimised system configuration was recommended to Metro Mondego.
Based on the conclusions from the system study, FERBRITAS and Metro Mondego decided to implement the preferred system. However, during the evaluation process, some of the basic parameters changed (new train paths, different rolling stock). Therefore, FERBRITAS decided to assess the preferred option in more details and commissioned ENOTRAC to conduct a further FABEL study. This covered the selection of the overhead wiring, the location of rectifier substations, and the quality of the power supply.
The scope of the planning phase included the assessment of stray current issues and the development of the return current and earthing concept. ENOTRAC started with the identification of vulnerable sites, possible weak spots within the system, possible measures and association data, in order to determine further actions. Later, a wide-ranging earthing, bonding, and stray current protection concept was developed, taking into account the relevant safety aspects, costs and usage. ENOTRAC developed guidelines for construction around the light rail (bridges, tunnels, rectifier-substations, but also other electrical installations such as ticket machines, light installations, communication system etc.) that are to be connected with the return conductor system, so that no dangerous situations occur and at the same time to guarantee the stray current protection.
ENOTRAC AG, Seefeldstrasse 8, 3600 Thun, Switzerland, Tel: +41 33 346 66 11, Fax +41 33 346 66 12
ENOTRAC SA, Avenue de la Gare 1, 1003 Lausanne, Switzerland, Tel: +41 33 346 66 19, Fax +41 33 346 66 12
ENOTRAC UK Ltd, Chancery House St Nicholas Way Sutton, Surrey SM1 1JB England, Tel: +44 20 8770 3501