Posted 1st October 2013 | 27 Comments

End of the line for the mile, the chain and the yard

PLANS being prepared by Network Rail will see the eventual end of the Imperial mile, chain and yard on the National Rail network, as a metric switchover takes effect during the next couple of decades.

The move will be triggered by the progressive installation of the European Rail Traffic Management System on selected routes between now and the 2030s.

The decision has been taken by the industry’s Technical Standards Leadership Group, Railnews has been told.

Although it will be necessary to permit the spread of metric-only ERTMS, the change will bring speeds and also locations, as presently indicated by mileposts, into line with the measurements already used on the rest of the railway.
Metres, kilos and litres have been standard for some time in such areas as civil engineering and rolling stock construction and maintenance, while the current Rule Book uses metric measurements as the primary units for distances, although speeds are still shown in mph.

The Rail Accident Investigation Branch also uses metric units by default, and translates the remaining Imperial terms where necessary.

The Rail Safety and Standards Board will now be assessing the implications of a further revision of the Rule Book and other documents to complete the changeover. At this early stage there are no firm costs or detailed timetable.

The traditional mileposts are expected to be replaced over time by new location markers at intervals of 500m or 1km. However, lineside speed restriction signs will become unnecessary in ERTMS areas, where information is given to the driver by screens in the cab instead.

Network Rail does have a derogation under the interoperability rules to show mph on cab screens as well, but a spokesman told Railnews that this option is ‘unlikely to be exercised’.

Some fully metric railways are already operated in parts of Britain. Apart from HS1, some London Underground lines and the ERTMS test area west of Shrewsbury, the country’s two segregated light railways in London and Newcastle have always been metric, while the speeds of modern trams are also measured in km/h.

Reader Comments:

Views expressed in submitted comments are that of the author, and not necessarily shared by Railnews.

  • Luke, London

    About time too! It is ridiculous that so much planning is done in metric, yet engineers are expected to convert to a system that is old fashioned and difficult to calculate in.

    The metric system is as easy to calculate in as decimal money.

    As for the UKIP supporters on here:

    1. I've travelled on French trains a lot and I've never seen separate male and female toilets.
    2. The metric system is common across the world bar the USA. Japan, China, Australia and New Zealand are all totally metric.

  • Bulldog Jack, London

    Good riddance to Imperial rubbish. Long overdue.

  • Chris, London

    As long as we do not end up like the Americans (with European help) miss Mars by a mile.

  • Red Shang, Hornsby, Australia

    Quite right, Derek. About time!

  • Set, High Wycombe

    How much does it costs to change signs saying different numbers on then so that people can see units that they're not naturally familiar with having no want or need to make these signs say different numbers? I'm assuming that people have not been marching down streets chanting "We want different numbers on our signs - when do we want 'em? When cash can be taken from individuals to pay for different numbers no-one wants.

    Hardly a tunefull chant!

    (Many people within and outside the rail industry are calling for metrication to be completed, because the present dual system is actually the more expensive and potentially confusing option.-_Editor.)

  • H.Gillies-Smith, BUXTON

    The legislation covering the statutory requirement for mileposts or stones is for railways promoted in England and Wales is Section 94 of The Railways Clauses Consolidation Act, 1845. Section 87 of The Railways Clauses Consolidation (Scotland) Act, 1845 covers those railways promoted in Scotland. These sections of the Acts will require stautory repeal or ammendment and perhaps, in the process, it will then become clear to people why the requirement for them was deemed necessary in the first place.

    (In fact, mileposts were originally required so that passengers could see that they were travelling the distance they had paid for.--Editor)

  • phil, Stockton

    ...and as an afterthought to my first post, these plans will change the entire network so that a relatively small percentage of high speed ERTMS equipped lines will be correctly signed. I'd have thought the simplest solution would be to dual sign those routes only... and leave the rest of the network alone.

    (More of the network is due to become ERTMS-controlled than you might think by 2026 or so. See this month's print edition of Railnews for an exclusive map.--Editor.)

  • phil, Stockton

    ah...maybe now I can go and legally purloin that 26 mp ii've had my eye on for the last 25 years as a house number marker for the end of my drive...

  • trackrat, Derby

    "There's going to be a lot of old mileposts ending up as garden ornaments in a few years' time!"

    Ah yes, that old unit of years. We gnomes of Brussels have been thinking of a relpacement unit for some time.

  • Gregory Darroch, London

    Further to what George Jasieniecki of West Brompton says, regarding tube railways and their location under the public highway, there is a fantastic dissertation on the subject on the internet. Just look up London's deep tube railways: visibly invisible and you can access the .pdf.

    If the surname on the dissertation looks familiar, that is because I want my brother to get me a nice Christmas present after I advertise his hard work. haha. Seriously though, it is very interesting!

  • Melvyn Windebank, Canvey Island, Essex

    Tony Benn first announced that the United Kingdom would go metric in 1965 that's nearly 50 years ago !

    All was going well until Thatcher was elected and she abolished the Metrification board and left the job half done with I reckon us being the only country with miles per Litre for fuel !

    As for chains they surely died out even earlier and yet distances in chains is often given in rail magazines when detailing new track or platform lengths.

    I was 13 when Tony Benn made his announcement and am now over 60 so those who argue about those used to imperial measures are talking about a rapidly declining number of people whilst those educated in metric measures are now the majority of the population .

    Bit like asking how many cubits will HS2 be to Birmingham ?

  • Simon Nicholson, Leicester

    I will be sorry to see the end of the mile, as the UK drags itself into the metric age by the inch. The main benefit I can see it will remove the confusion of the S&T using Miles and Yards and the P Way using Miles and chains.

  • George Jasieniecki, West Brompton

    Tony Pearce of Reading is mistaken to assert that some Tube lines have 'already changed and drive on the other track under central London'. With each line isolated in its own tube, its spatial relationship with the other track is irrelevant. These lines were originally constructed (1900-1907) to be contained within the widths of the streets above, and not stray under buildings. Generally the 'direction' of running is the conventional British one of left-hand running, but at a few locations where the streets above were narrow, the lines were built one above the other. At a very small number of locations they then 'rolled over' so give the impression of running 'wrong road', but they soon revert to the normal arrangement.

  • Greg Tingey, London

    And,how, if the mile-posts are missing, will one be able to calculate train-speeds if not using GPS?
    Also, isn't there an Act of Parliament COMPELLING railway companies to put in & maintain mileposts?

    For most uses, of course MKS units are a really good idea

  • John Hartshorne, Stafford

    That finally puts "The Prize Length" to bed. Pity, what would ganger Slim have to say about his beloved platform 7&8 at Snow Hill?

  • Gavin Kirby, Glasgow

    This is a commonsense modernisation, which could not have come 1 BTU/hp too soon. Metrication was not introduced by the dreaded EU but by British industry in the 1960s, because the metric system is far more practical for any kind of industrial, engineering or scientific purpose. It's at least equally good for everyday life, too, as evidenced by the fact that it's used universally by ordinary folk in the rest of Europe.

    Metres per second is a useful unit in some contexts, such as vertical speeds, muzzle velocities and sometimes wind speeds. It makes sense to pick the unit that's appropriate to the given situation. There are lots of cases where speeds are given in km/h (speeds of balls in sporting events) where m/s would be more meaningful.

    m/s^2 is given because it's the standard SI unit of acceleration, but km/h/s is more directly meaningful.

  • Chris, Longstock

    (Ho, ho, Tony. Except that most French and Belgian trains keep to the left. Strange, but true.--Editor)

    Knowing the UK with it's love of Roman Empire rules and regulations, our trains will switch to right just for the sake of it. A good use of the scissor crossings in the Channel Tunnel.

  • Paul Hepworth, YORK

    I recall with some glee the two parallel railways that run between Peterborough North and Helpston. The ECML has mileages that increase northbound, while the former midland lines mileage increases southbound. There was a mileage conversion chart kicking around for these routes. Didn't half cause confusion when trying to establish TSR warning board positions.
    Likewise the railway from Barnsley to Pensistone enjoyed at least three different mileage sections, all remnants of the former railways that survive to make up this route.

  • Richard, Maidenhead

    Not before time! For how much longer must road users struggle along with obsolete units?

    Mileposts could of course be reused and repositioned as kilometre posts, but I expect new ones will be used.

  • Bill, Cardiff

    Anyone with a background in science or engineering will appreciate that one of the main benefits of SI units is the lack of a fog of constants in calculations.

    But I do wonder if the ability to visualise things in human terms is perhaps more important than generally acknowledged. Architects and no doubt carriage designers work in mm, not metres. Do they really visualise their design when they say that seat spacing is, say, 745mm? (Perhaps this is why, unlike comfortable BR Mk I carriages, the seats on new trains never line up with the windows!)

    Speeds in km/hour are perfectly clear. No one would seriously suggest using the SI unit of metres per second for everyday use. And yet, rail vehicle manufacturers do just that sort of thing when they quote the acceleration of new trams in metres per square second! Why?

    The era of the modern tramcar began with the PCC car in the USA. These vehicles provided a road traffic compatible acceleration of up to 5 mph per second. One could understand that as 8 km/hour per second. So, you'd expect to reach 25 km/h or 15 mph in about 3 seconds. One can still observe this initial rate of acceleration when standing behind the driver in say, a modern Brussels tram with electronic motor control. Now, a Croydon tram offers 1.3 m/s2 - that’s uhm…?

    (The town councillor selecting a tram will of course know at once that 1.3 metres per second squared is 4.7 km/h per second, or about 3 mph per second!)

    SI is fine, but there’s perhaps also a need for metric but ‘human friendly’ units!

  • Ray Matthews, Aylesbury

    Another diktat from that bunch of tossers in Brussels. My ancestors fought in 2 World wars to liberate Europe from tyranny and this is the thanks we get for liberating them. To the half wits of Brussels we don't want your stupid laws and rules, we are quite capable of governing ourselves which we have done for 100s of years before you lot came along! PS We invented the railways and sent this technology all over the world!!

  • Tony Pearce, Reading

    Its even worse than the article suggests. The EU is proposing all trains have 2 Toilets one for men and one for women as on French trains. Not only that they are proposing that all British trains 'drive' on the right so that European Drivers don't get muddled when they run their High Speed Trains on our network via the Channel Tunnel. (The Underground lines of Victoria, Northern and Central already have changed and drive on the right under Central London.) This will be first introduced on HS2 should it ever be built. They are also specifying that the distance between the 2 rails be adjusted to 144 centimetres instead of the old 4 foot 8 inches. And last of all the EU is appalled at the lack of safety in stations and on footbridges when hordes of people just barge into each other and do not keep to left or right. Compulsory markings on the floor will show which side passengers should keep (on the right again of course). I think I'm joking - aren't I ?

    (Ho, ho, Tony. Except that most French and Belgian trains keep to the left. Strange, but true.--Editor)

  • Derek Rimington, Brighton

    About time too!

    I’ve been using Rationalised MKS Units (now called SI) since we were taught them at Royal Technical College, Salford in 1950.

    They certainly make power and energy calculations very much simpler compared with the antediluvian Imperial units.

  • Chris, Longstock

    What's wrong with the "old Christian units" of measurement. Having been brought up with metric, with all the problems of decimal point in the wrong place and whether its hm, m, cm, dm or mm; the engineering companies I deal use imperial as well to avoid mistakes and it's easier to visualise.
    According to the EU; each member country can use units or measurement which are clearly understood by its people. Changing the units, apart from being a waste of money, probably makes money by having to change apparatus, signs, maps etc.
    Rather like the paint manufacturers like it when the franchises change - again.

    "Prize Mile", the "six-foot way" and "Goods Yard" - RIP!

  • Tim Price, Bestwood Village

    I'm totally against this because, apart from the confusion that will be caused to those traincrews who will not have the benefit of ERTMS on all routes for many years, it's just not British. The system of Imperial measurment is just fine and forms part of our national identity.
    At the very least have dual measurements until the last of us dinosaurs have retired!

    (And when does that happen? There is always another generation of not quite so old dinosaurs coming along behind!--Editor.)

  • dogsauce, Leeds

    There's going to be a lot of old mileposts ending up as garden ornaments in a few years' time!

  • Jim Campbell, Birmingham

    As someone who has used metric units at work for over 40 years I have no problem with this. However, as a nostalgic railway enthusiast can I ask Netwrok Rail to leave the old mileposts in place. I'm sure the new "Location Markers" will be sufficiently distinct that there would be no chance of any misunderstanding.
    It will save money as well, as taking things out costs.