ELECTRIFICATION & ELECTRONICS
“You’ve also got point-of-sale equipment in stations; ticketing facilities; passenger information displays; lighting; PA systems; two-way communications of all sorts.
“External to the railway, where we have little control; there are base stations very close to our railways, and then things like handsets. We take them onto the trains with us.
“At peak loading on the Victoria Line at 9am, you’ve got 1,000 people, over 90% of them will have a mobile phone – what’s go- ing to happen to their signals? They will all start looking for their networks and ramp
up to maximum power. There’s a potential threat there we need to be concerned with at those frequencies.
“We’ve also got broadcast frequencies which are there all the time: radio and so on. They should not interfere. There’s also industrial equipment or welding equip- ment, all out of our control.”
The authorities have recognised the poten- tial problems, and there are EU directives on EMC and interoperability which apply. Network Rail and London Underground also have their own standards.
Reiterating his central point, Marshman said: “EMC is not an add-on; it’s about making sure our products are fi t for ser- vice. With good engineering design, we will meet the EMC and interoperability re- quirements anyway.
“But we need to be aware of the best prac- tice approach to EMC. We need to identify hazards and know what threats are pre- sented by our trains to the outside world. We need to make sure we’re controlling the hazards within the railway – that we’re not presenting a threat to our signalling system from our rolling stock.
“We need to establish an EMC specifi cation for our railway, to know our targets – prob- ably based on the offi cial standards, plus the results of our hazard identifi cation, maybe also relying on a range of Network Rail standards, if we’re looking at Network Rail projects, which cover different types of track circuit.
“We then need an overall EMC manage- ment plan, where we say what we’re going to do and how we’re going to achieve EMC for our railway, how we’re going to control our suppliers and who has which responsi- bilities within the overall operation.
“We then need to audit our suppliers’ equipment and ensure it doesn’t produce interference issues. That leads to things like producing test results and putting that in a compliance log.
“We need to ensure we use good EMC prac- tices in the way equipment is installed. It’s no good having a CE marking on each indi- vidual bit of kit, and then to use bad prac- tices in the way we install it – it defeats the object.
“Finally, when we’ve got everything togeth- er, we need to ensure it’s what we intended to have. We need to do on-site testing to verify what we’ve done, and to do testing at the outset too so we’ve got a baseline to measure against.
“It’s not rocket science. It’s about being careful, good planning, testing, and good engineering.”
Chris Marshman is managing director of York EMC Ser- vices Ltd. This is an abridged version of his presentation at Railtex 2011.
Chris Marshman
FOR MORE INFORMATION Visit
www.yorkemc.co.uk
rail technology magazine Jun/Jul 11 | 89
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