Challenge B: An environmentely friendly railway Safety for human beings and pipelines: a new approach in workshop design

Traditionally in workshops conflicts arise between requirements for the safety of human beings and requirements to prevent stray currents. Within workshops more strict limits for step and touch voltages apply than for the rest of the railway system. These requirements can be met in case the running rails are connected to ground, but this will increase stray currents. As The Netherlands is a very densely populated area, for reasons of economy of space nowadays infrastructure is more often bundled. This can lead to an increase of interference between various infrastructure components. In the case of the new workshop and stabling yard “Beverwaard” the functions of workshop and stabling yard have been combined with a parking garage, while at the same time a number of high capacity, high pressure gas transportation pipelines and a major highway are in close vicinity. The classical approach of grounding the running rails can no longer be followed, as this would lead to an increase of stray currents in the soil, which is not admissible due to the pipelines close by. Therefore a new concept has been developed which can meet all requirements. The new concept has been based on an integral earthing concept, integrating safety earthing, lightning protection and using civil structural assets, based on the philosophy of IEC 61000-5-2 [1], which has excellent EMC properties. Running rails are insulated from the substructure, and grounded at one location. A rigorous bonding strategy ensures very low step and touch voltages. With respect to traction power supply the workshop is an island, fed from a dedicated substation. A benefit of the concept chosen is that complex machinery as a wheel lathe can be incorporated in the design in a relatively easy way. For the insulation of running rails a new approach has been chosen: to use PUR foam, as this is both light and is insulating. Measurements of the insulation quality have been performed over a long period of time to assure that the insulation quality is stable over time, even in very wet adverse conditions. Simulations have been performed to determine the effect of the chosen solution on the adjacent pipelines. Both the starting situation (without workshop) as well as the end situation (with workshop) have been studied. For the simulations the Movares tool STARTRACK [2] has been used. It can be concluded that it is possible to integrate railway infrastructure with susceptible pipelines and at the same time guarantee safety of human beings and installations.