Normally, posting from one list to another is a no-no. But this came from a passenger rail-oriented discussion list to which I also subscribe, and came without any prompting. It's a rather interesting comment on metric use on railroads.
Carleton _____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of merccurytravel Sent: Friday, January 18, 2008 16:48 To: RailNews; all-aboard Subject: [A_A] Standards Rail Manager on Line- On 23 September 1999, a NASA spacecraft costing $125m was lost because of a confusion between metric and imperial units. An inquiry into the incident quickly discovered that two crucial groups of engineers had been working with different systems, so that their calculations, when combined, were at fault. The misguided spacecraft, a Mars Orbiter, overshot that planet and is probably still uselessly going around the sun now. The point of this story is that in spite of this dreadful warning, another safety critical industry is still using both systems of measurement today. It is very much closer to home and yes, you've guessed it - it's our railway. Of course, the railway ran perfectly well on imperial units for 150 years or so. Miles per hour to measure speed, miles and chains for distance, feet and inches for rolling stock and structures. It could still do so today, except that the rest of the world (almost all of it, anyway) has moved on. So new rolling stock is measured in metres, and so are platforms. Some trains are being driven according to km/h, not mph. The example which comes to mind is probably Eurostar, but some London Underground lines also work in km/h, as do modern trams. It is tramways which have introduced the first km/h speed limit signs on British roads: those figures in white diamonds for tram drivers are in km, not miles. And the rest of the railway has started to switch, too, although not always in a controlled manner. A platform sign at Dunfermline Town announces: 'Signal EO714 276M'. Since, at a rough guess, a signal 276 miles south of Dunfermline would be somewhere the other side of Retford, that M must stand for metres. Yet the train is being driven to mph, and all the speed limit signs and documention are imperial too. Although yards and metres are similar enough for most purposes, the effect could be enough to distract a driver for a moment. It's not in the common tongue. Similar confusion abounds in releases and announcements. Here's one from Network Rail: The Track renewals team achieved good levels of output with 34.55 composite km of Plain Line track delivered . A total of 17 km of new wiring was delivered ... The remaining 3.5 miles of route were buried with turning chambers provided every 150 metres ... Additionally, some 2500 yards of plain line track was also re-laid ...' All those statements come from the same document. In short, it's a mess. Do we measure our railway in miles or km? Do we divide miles into yards or metres? This problem is arguably an echo of British society. Some countries are bi-lingual, but the UK seems to be the only one which is bi-measurement, and a great deal of time is wasted as a result. Shops must sell in metric units, but may sell in imperial too. The roads remain firmly imperial for now, and aircraft still seem to measure their altitude in feet, but the rest of the professional and trade world has long since measured its paint and petrol in litres, its tiles and wiring in mm. But the railway's hand is now starting to be forced. The ERTMS trials in mid-Wales will be metric only. Network Rail has conceded that there is no point in inventing a British [=imperial] version. In the name of interoperability, one would hope not, indeed. As ERTMS spreads, so must metric working. Drivers on ERTMS routes will drive to km/h, because there will be no choice. Surely it would be better for Network Rail to grasp the metric nettle now? A phased changeover, properly planned, will be infinitely preferable to a chaotic mixture. Remember that NASA craft. It's still out there somewhere. Tony Bailey
