Why do Network Rail still use some imperial measurements?

[alxndr]

Signalling plans have metric on them now if they have been updated.

The plans I use are primarily in imperial although the metric conversion is also shown. They are dated 2019.

Frustratingly, the location cases have been numbered using a bizarre system [ELR][mileage][line][meters divided by 10], so for example ABC054U102 would be at 54 miles 1020 meters on the Up side of the hypothetical line with the ELR (Engineers Line Reference) of ABC. This mixing of Imperial and Metric measurements within one name winds me up as there's no need for it and meters are meaningless to me when everything else is marked up in miles and chain. Thankfully converting it to miles and chain is straightforward, as a chain is 20.1 meters simply dividing the final numbers by 2 gets you close enough to identify where you're going, in the example 54 miles 51 chain.

On older diagrams it was common to see things given in miles, quarter miles, and yards, which took a little more mental maths, but was at least logical.

 

[Andyjs247]

Signalling scheme plans are generally metric where they have been updated. However the 5 mile diagrams which are widely used to show the locations of structures are fundamentally in miles and chains. Unless there is a particular reason to remeasure and rebase everything on a given line of route I don’t see that changing any time soon.

 

[notverydeep]

And who learns basic units of measurement in school? Surely you learn the basics at home?

Which is a key reason why imperial is so persistant despite being out of the curriculum for decades. I was taught only metric at school, but only in later life have I taught myself to overcome my parents' bias towards 'casual' imperial, which they had inherited from their parents. I had to learn to think of my height as 177 cm and my weight (mass?) as 84 kg rather than the imperial I picked up. I want my children to be all metric, but unfortunately they still see miles on UK road signs.

That does prompt a question, I heard when working for a London Borough a couple of decades ago, that distances described as yards on (at least modern) UK road signs aren't really yards at all and are actually measured to the same number of metres. Does anyone know if this is actually true?

Back to the actual topic in hand of this now separate thread. Is the National Rail network actively converting to metric distances, or are even new signalling installations or routes designed metric, but then converted to imperial for operational consistency ? This was part answered seconds before I posted, by the two previous posts, but it would be interesting to know whether a particular plolicy is being followed...

 

[coppercapped]

Because we still use imperial measurements in some areas. Literally everyone* else uses metric.

*Apart from the USA, which as far as I'm aware uses (American) imperial measures almost exclusively. Personally, I can't get my head around using ft-lbs etc for engineering calculations; yet I still use miles when measuring distance (and metres/feet for shorter lengths!)

Bicycle tyre sizes in Germany are in inches...

...and the 100mm drain pipe was originally a 4" drain pipe!

 

[Freightmaster]

You Brits are weird...

Username doesn't check out...




MARK

 

[Mcr Warrior]

When I left school, metres hadn't even been invented !

How long ago was that? Wasn't the metre invented sometime in the 18th/19th century?

 

[William3000]

I wonder why they've used a mixture of yards and kilometres? Seems a bit odd; I'd have thought they'd use either fully metric or (less likely) fully imperial

HS1 is in metric with speed limits in km/h rather than mph; I suspect HS2 will be the same. They have rounders with white numbers on black backgrounds instead of black numbers on white boundaries for mph. I’m pretty sure that the Tune & Wear metro, and possibly the Croydon Trams are metric as well.

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I left school in 2000 and was taught a mixture of imperial and metric so the under 60 thing isn't quite true!

I left school in 1997 and was only taught in metric, though teachers did use imperial measurements colloquially on occasions but not in science, maths, geography, physics etc.

 

[edwin_m]

Well the USA/NASA managed to get to the moon (allegedly) using nautical miles for distances and feet/sec2 for rocket burns!

But didn't they lose a Mars probe because different people were using different units?

Luckily for you (and for me!) most tape measures have proper measurements - plus metric ones as well!

Yes, but it's quite annoying that you have to use a tape measure or ruler a particular way round so the side with the units you want to use is next to what you're measuring.

 

[William3000]

It's traditional, like buying petrol in £ per litres but measuring it's use in miles per gallon

Like most people I know I use a mixture of both depending on circumstances, for instance miles and proportions of them for longer distances, centimetres and millimetres for smaller ones, unless it actually works out as an imperial measurement, which is often the case when doing anything around the house, it having being built in imperial. As I don't have to measure them precisely yards and meters are practically interchangeable for me, while human heights and weights I measure exclusively in imperial, my cat's weighed in metric.

Litres to the 100km makes more sense as we know the cost of fuel in litres but not in gallons.

 

[brad465]

Do chains exist specifically for railway purposes, as I don't recall seeing them in use anywhere else?

 

[Mcr Warrior]

One chain = a cricket pitch length!

 

[Annetts key]

Signalling plans have metric on them now if they have been updated.

Depends when they were produced or amended. On the older ones, the only metric information is the TPWS details. On the newer ones, nearly everything is metric. The mileposts are indicated in both miles and metres, and the speed restrictions are shown in MPH.

Frustratingly, the location cases have been numbered using a bizarre system [ELR][mileage][line][meters divided by 10], so for example ABC054U102 would be at 54 miles 1020 meters on the Up side of the hypothetical line with the ELR (Engineers Line Reference) of ABC. This mixing of Imperial and Metric measurements within one name winds me up as there's no need for it and meters are meaningless to me when everything else is marked up in miles and chain. Thankfully converting it to miles and chain is straightforward, as a chain is 20.1 meters simply dividing the final numbers by 2 gets you close enough to identify where you're going, in the example 54 miles 51 chain.

On older diagrams it was common to see things given in miles, quarter miles, and yards, which took a little more mental maths, but was at least logical.

Question: did anyone explain the ‘modern’ location case ‘numbering’ or did you work it out? No one explained it to us. It had me scratching my head for a while…

Back to the actual topic in hand of this now separate thread. Is the National Rail network actively converting to metric distances, or are even new signalling installations or routes designed metric, but then converted to imperial for operational consistency ? This was part answered seconds before I posted, by the two previous posts, but it would be interesting to know whether a particular plolicy is being followed...

With new signalling schemes, the existing infrastructure is surveyed in metric. The new or altered signalling is then shown using metric distances. ‘New’ equipment always uses metric measurements (e.g. TPWS, ATP).

Do chains exist specifically for railway purposes, as I don't recall seeing them in use anywhere else?

The distances between ships at sea was at one time measured in chains. As a child, I once read an old book about a ship at sea, that kept going on about chains. Which was very confusing at the time, as I did not know that a chain was a unit of measurement of distance!

 

[InOban]

External exams?
5 'O' & 3 'A' level passes.

And did none of these include units of measurement? Surely they must have been metric.

 

[td97]

Railways are miles & chains / yards, speed is mph, drain pipes are in inches.

Even though defined in miles and chains using mileposts on the ground, a project or design "chainage" is used for design. Usually it's the miles and chains converted directly to metric
E.g. 12 miles 63ch = 20579m
Thereafter metric is used as the basis for a design.

Rails are specified in metres, for CEN56 one rail length is 18.288m (which is exactly 60ft but always quoted in metric).

The only continued imperial measurement in railway design is speed which often needs to be converted to m/s for calculations anyway.

 

[Frankton Junct]

When I was at school in New Zealand in the 1960's we were taught only in metric - we were told that 'home' (i.e. Britain) was planning to join the Common Market and so imperial measurements would be obsolete in a few years. Oh the irony!

New Zealand converted entirely to the metric system (I assume the railway did too), including all road speed limits (as far as I remember that was done overnight).
The most difficult new measurements were those measured on a different base; e.g. litres per 100km rather than miles per gallon.

I am annoyed when the nurse tells me my weight in imperial measurements. To me a stone is just another name for a rock.

 

[LNW-GW Joint]

Signalling scheme plans are generally metric where they have been updated. However the 5 mile diagrams which are widely used to show the locations of structures are fundamentally in miles and chains. Unless there is a particular reason to remeasure and rebase everything on a given line of route I don’t see that changing any time soon.

For at least 30 years (starting with the ECML I think), electrification masts have been identified by metric distances.
All ETCS equipment (in cabs and on the track) is in metric (eg on the Cambrian).
HS1 is metric and so will HS2 and any other new lines be.
LU is measured in metric.

Having said that, HS2 Ltd announced last month that TBM Florence had bored its first mile under the Chilterns, not its first kilometer!

 

[Irascible]

Left school at the end of the 80s & was mostly taught metric, some basic imperial measurements too ( quite a lot as illustrations of how stupid not using metric can be ). However having done a lot of sailing & a little flying I'm used to judging distances & speed in NM/feet & knots, at least. Aviation is generally moving *to* imperial for heights & speeds as far as I can tell.

Converting mph<->kmh mentally becomes pretty easy & ofc estimating feet<->metres isn't hard either & so on, so day to day life with both isn't really a problem. On the other hand I've no idea how to estimate someone's height in cm

Often find people will use whichever unit is a) nearest and be) quickest to say, I think one reason why we still casually use inches & feet. Mebbe we should start casually using millimetres, you can shorten that to "mil"...

 

[Meglos]

With the exception of China, Russia (and most CIS countries). the *whole* world measures the height aircraft fly at in 100's of Feet above sea level. Airways are generally set out in 1000ft levels. Below what is known as the transition altitude this is true feet above the ground based on local air pressure at sea level, and above the transition altitude feet are used based on the the air pressure being 1013.25HpA (hectopascals). The US however uses a pressure setting of 29.92inHG (inches of mercury), which is in fact the exact equivalent of 1013.25HpA.

 

[1955LR]

Left school at the end of the 80s & was mostly taught metric, some basic imperial measurements too ( quite a lot as illustrations of how stupid not using metric can be ). However having done a lot of sailing & a little flying I'm used to judging distances & speed in NM/feet & knots, at least. Aviation is generally moving *to* imperial for heights & speeds as far as I can tell.

Converting mph<->kmh mentally becomes pretty easy & ofc estimating feet<->metres isn't hard either & so on, so day to day life with both isn't really a problem. On the other hand I've no idea how to estimate someone's height in cm

Often find people will use whichever unit is a) nearest and be) quickest to say, I think one reason why we still casually use inches & feet. Mebbe we should start casually using millimetres, you can shorten that to "mil"...

I took my HNC engineering examination in 1968, and I believe that was the last one in imperial units. The next year was SI units . I did a a resit of my Applied heat in 1969 and that was SI units. I then spent the rest of my working life in the motor industry using both and initially having to continually convert from one to another all the time .

 

[philthetube]

Not London Underground - mostly metric now...

When Sstock was introduced 10 years ago the decision was made to keep the speedo in mph, drivers understood this and all signage was in mph anyway.

Do chains exist specifically for railway purposes, as I don't recall seeing them in use anywhere else?

I think they are used by architects to measure arches but am not sure how that works.

For info.
10 chains in a furlong,
8 furlongs in a mile

The chain must be a good unit as the French use them to measure their racecourses.

 

[Irascible]

With the exception of China, Russia (and most CIS countries). the *whole* world measures the height aircraft fly at in 100's of Feet above sea level. Airways are generally set out in 1000ft levels. Below what is known as the transition altitude this is true feet above the ground based on local air pressure at sea level, and above the transition altitude feet are used based on the the air pressure being 1013.25HpA (hectopascals). The US however uses a pressure setting of 29.92inHG (inches of mercury), which is in fact the exact equivalent of 1013.25HpA.

Russia is moving to QNH/feet, slowly.

Transition altitude is a whole other off-topic minefield.

 

[Andyjs247]

For at least 30 years (starting with the ECML I think), electrification masts have been identified by metric distances.
All ETCS equipment (in cabs and on the track) is in metric (eg on the Cambrian).
HS1 is metric and so will HS2 and any other new lines be.
LU is measured in metric.

Having said that, HS2 Ltd announced last month that TBM Florence had bored its first mile under the Chilterns, not its first kilometer!

Crossrail is also all metric and I expect the Bedford to Cambridge section of East West Rail will be too. However some some shorter links, eg the Bicester South West Chord has mileposts and is measured in miles and chains despite being a fairly recent (2015) brand new line of route. The rest of Bicester to Oxford has mileposts and wasn’t remeasured when directions changed. I guess (as is so often the case) it depends.

 

[GRALISTAIR]

A quarter pounder is a “Royale with cheese”

 

[1955LR]

Are the Fishplate bolts on jointed track still Whitworth threads ?

 

[Gonzoiku]

That does prompt a question, I heard when working for a London Borough a couple of decades ago, that distances described as yards on (at least modern) UK road signs aren't really yards at all and are actually measured to the same number of metres. Does anyone know if this is actually true?

Modern road signs advising a layby ahead use multiples of 220 yards - otherwise known as 200 metres, to judge only by the signs I see.

In other words, yes.


== Doublepost prevention - post automatically merged: 8 Nov 2021 ==

A quarter pounder is a “Royale with cheese”

How is "Royale" consistent with "Imperial"?

GZ

 

[MarkyT]

Signalling plans have metric on them now if they have been updated.

Yes items are usually dimensioned in metres from a common datum for an area or project, quite possibly at a milepost!
Sectional Appendices often show feet and metres and sometimes SLUs for goods loop standage, platform lengths etc (SLU=21ft)
I understand mileposts are difficult to remove legally because the extents of railways as originally drawn and constructed were defined in miles and chains in the Acts of Parliament authorising them and giving them continued powers to exist and operate.
Speeds are usually shown in mph as on UK roads except in ETCS areas where kph has been used so far but the EU TSIs apparently allow(ed) UK to continue using mph in this system if they so desired, and it's fairly trivial for a metric calibrated computer system to do such conversions in real-time.
As a young designer in the WR signalling drawing office back in the 1980s, it was essential to become proficient in working with and converting between both systems.

== Doublepost prevention - post automatically merged: 8 Nov 2021 ==

Depends when they were produced or amended. On the older ones, the only metric information is the TPWS details. On the newer ones, nearly everything is metric. The mileposts are indicated in both miles and metres, and the speed restrictions are shown in MPH.

I learned quickly that mileposts/quarter mileposts are rarely exactly the stated fractional imperial distance apart. They may not accurately reflect historic changes in section length after minor realignments if say a curve has been eased in the past. Doing a proper survey to determine metric distance between each is very useful and allows them to continue to be used as local datums. Hence the common reference in engineering activity to miles and metres, i.e. so many metres from the appropriate milepost.

 

[AM9]

When I left school, metres hadn't even been invented !

So you left school before 1793?

 

[AndyPJG]

Do chains exist specifically for railway purposes, as I don't recall seeing them in use anywhere else?

A 'chain' is a land surveying instrument of that length, made up of 100 wire links, the length of each link being a unit of measure in its own right.
100 links = 1 chain, 10 chains = 1 furlong, so a link.
Sadly I'm old enough to have used one, albeit only once when a student civil engineer. (also staffs used in level surveys were/are marked in feet and hundredths thereof.)

 

[alxndr]

Question: did anyone explain the ‘modern’ location case ‘numbering’ or did you work it out? No one explained it to us. It had me scratching my head for a while…

Was left to us to figure out. It took us a while as well, and I'm still not sure some people have figured it out! It's definitely not an intuitive one, I think it clicked for me when I realised that the final number never went above 159!

Are the Fishplate bolts on jointed track still Whitworth threads ?

Not sure on fishplates but there are still WW threads out there, e.g. on some points.

 

[RPI]

And who learns basic units of measurement in school? Surely you learn the basics at home?

I'll be honest I can't remember at what point I learnt my first unit of measurement, I was probably still eating mud and pulling legs of spiders.

Even now I generally use feet, centimetres and miles, I find centimetres and millimetres easier for measuring smaller stuff, feet and yards for slightly larger stuff and inches for things that are in between!

Having grown up around the fishing industry I used to also measure ropes in fathoms!

It comes down to what you're used to, volume I generally use metric other than for milk and beer!

As for kilometers, thats a unit I never use and if something is quoted as such I have to use a calculator to work the mileage out otherwise my brain just can't compute it, it just means nothing to me.