Marking on rails

[ainsworth74]

Hi,

Quick question, I was out walking the dog along the old Middlesbrough & Guisborough Railway and finally got to where it joins the Esk Valley Line, at that point you can actually walk right up to the track theres no fencing! On one of the rails I saw this marking which was 5m 30ch. Im wondering what it means, at first I thought 5 miles 30 chains, but chains is such an old measurement that it can't actually mean chains can it? So what is 5m 30ch?

Thanks
Ains74

 

[bengley]

It is chains.

 

[GB]

Chains are still very much still in use (dont ask me why), so your initial theory is correct.

 

[Hydro]

Chains are still extremely common on the railway. Some areas use yards as well. On my patch we use miles and chains almost exclusively, with the exception of recording tamping mileages, which is in miles and yards.

 

[Old Timer]

We still do measure distance in Miles and Chains, apart from the Scottish Region where the measurement is miles and yards.

The use of chains derives from the Imperial system, and as I doubt the origins of the Imperial system are taught or even known about these days I will take the liberty of explaining it to you.

Although the measurements in the metric system are derived from scientific principles, the English units measurements (and the subsequent USA and Imperial measurements) are based on nature and everyday activities. For example, a league is based on the distance that can be walked in an hour. Sailors (in days gone by) would drop a weighted rope into the water, lowering it by lengths (where each length was measured by holding the rope between their outstretched hands) until the weight at the end of the rope touched the seabed. This led to the definition of the fathom as the distance from the fingertips of one hand to the fingertips of the other, when the hands are held straight out to the sides. A grain (used to measure small quantities of precious metals) is the weight of a grain of wheat or barleycorn.

As trade and commerce grew, it was necessary to have more consistent measures (after all, not all grains of wheat have the same weight and not all sailors have the same length of arm). Consequently, metal weights and lengths were produced to represent exact measures; these metal representations where then used to produce official scales and measurements to ensure that trade was based on standard quantities.

For larger measures (e.g. a mile) it was impractical to build a metal equivalent, so they were redefined to be multiples of the smaller measures. It is for this reason that the mile was changed in 1595 under Queen Elizabeth I's reign from the Roman standard of 5000 feet to 5280 feet.

A Yard is said to be the average distance between the tip of the nose and the longest finer of an outstretched arm.

A Chain is 22 yards, which is the length of a cricket pitch

There are 80 Chains to a mile.

In olden days such measures made sense and were easily judged however today things are less simple for all sorts of reasons.

In track design today, Renewals sites are designed in metric. To do the job correctly therefore the start point is identifed and wheeled out in metric.

Excavation depths, cant, ballast depths and all other measurements are undertaken in metric.

NR is now on a course of installing metric markings as fewer and fewer people can judge Imperial distances, even though legally the Imperial system is still the only legal distance measurement system in the UK.

 

[ralphchadkirk]

Thanks OT, never knew an easy way to measure chains! I was brought up in metric..

 

[SWT Driver]

Imperial?

Whoosh... Just gone straight over my head!

I was in a year where one term we were being taught Imperial, when we came back from the Summer holidays we were told to forget Imperial measurements, it was all metric & that was the way forward.

I've long since forgotten how many yards make a mile all the rest of it, it's pretty much gibberish, but then again I'd imagine that to people who're a lot older than me, metric is just as mysterious to them as Imperial is to me.

 

[Old Timer]

Taught properly, the Imperial system makes sense being based upon nature and natural things.

 

[SWT Driver]

I'll have to take your word on that.

Metric is just dead simple.

 

[djw1981]

Metric is easier with a measure, and for mental maths but harder to visualise.

 

[Mojo]

NR is now on a course of installing metric markings as fewer and fewer people can judge Imperial distances, even though legally the Imperial system is still the only legal distance measurement system in the UK.

Avoiding the point that the only true "measurement system" is SI (imperial being merely a collection of units), I'm going to have to dispute that claim about it being the only legal system, as since 1963 Imperial units are defined in terms of metric and thus, the details on any new transport projects have to be submitted and worked in metric, by law.

You may see "200 yrds" on road signs, but the distance between the sign and the datum is actually measured as 200 metres, according to the Traffic Signs Manual. Similarly 1 mile according to the signs is actually 1600 metres (yes, not even the more correct 1609.3 metres).

 

[Old Timer]

I bow to your more uptodate knowledge, Chap however although the UK completed its legal transition to SI units in 1995, many imperial units are still in official use:

• draught beer must be sold in pints ;
• road-sign distances must be in yards and miles ;
• road-sign length or width (but not weight) restrictions must be in feet and inches (although an equivalent in metres may be shown as well), and ;
• road speed limits must be in miles per hour, therefore instruments in vehicles sold in Britain must be capable of displaying miles per hour.

 

[Mojo]

Yes, the signs must be in yards and miles (unless they are private signs (eg. if I ran my own car park, I can limit vehicles to 200kg)), but the distances which they represent MUST have a metric value. You may have seen markers along major roads and Motorways, and many of them are now enlargened - these are in km as that's how the roads were built!

It's still pretty barmy though, we're one of three countries in the world that hasn't finished it's metrification yet - let's get on with it and use a proper system, and one that makes sense!

I do seem to surprise some people when they ask how tall I am, and I say I am 1.83m and weigh 64kg, and when they say they are 6ft and weigh how ever many pounds I have to ask them to convert into English! Everything I do is in metric, even when driving (which I do so rarely since I live in Birmingham) I say to myself that I am going 50km/h and travelling 1.6km even though the sign says 30mph and 1 mile.

 

[Surreytraveller]

I was taught metric at school, then left and used imperial. What I was taught was of no use!

 

[Crossforth]

I think if we went to metric, we would need to put, for want of a better phrase, bi-lingual signs in (miles and Km) so that everybody can at least understand one lot of signs

 

[yorksrob]

Yes, it's interesting, I grew up with metric and for many years didn't know anything else. However, since I've been doing a job for a while which involves talking about widths and thincknesses to people older than myself, I now tend to think in feet and inches. Don't ask me to add them up though.

Ale should always be in pints

 

[Trog]

Has anyone else noticed how many metric sized objects, work out to nice round imperial sizes when converted back into English?

It is also strange how people keen on Imperial measure tend to want people to be allowed to choose which system to use, or have things dual marked. Where Metric lovers tend to be keener on compulsion to force everyone to use their favourite system.

 

[jopsuk]

Metric sized objects that come out as round imperial sizes tend to have been imperial in the first place.

Not all people keen on the Imperial system are happy with allowing dual labeling- there are walking tails in the York area that have/had no distances on the markers, as the council erected them with kilometre markings (partly on the basis that OS maps used by walkers are metric). The council were taken to court by anti-metric comapigners on the basis that lgeally they counted as road signs, and so were forced to cover the distances up. One of their members said with regards this

"Each time we are successful [in getting metric signs changed], it is a small but significant step towards eradicating them from our country

Anti-metric sentiment often 9though not, I'll grant, always) seems to go hand-in-hand with moral and social conservatism, europhobia and (as evidenced by the website linked) borederline islamophobia/racism. The truth is that as very few children are taught about the Imperial system, excpet as needed with regards the likes of roads, the twentieth century version of it will die off in this country as previous units have died off before hand.

 

[Wyvern]

Giving combined measurements can be tricky.

Just after metrication came in the rule was both were to be specified on any job and I had a rather complicated piece I wanted our model makers to produce for me.

Conversions for each dimension had to be rounded off to a couple of decimal places and therefore produced cumulative errors. In the end I gave it up and produced two designs - one imperial and one metric.

I specifically warned the model maker to use either one or the other system but not to mix them.

He didnt listen and it took him about a fortnight to come back and complain my measurements didnt match up.

As a footnote we used quarter and half inch Dymo Tape. It began to be sold in ten foot instead of twelve foot lengths - because of decimalisation. You couldn't make it up.

 

[Oswyntail]

...Although the measurements in the metric system are derived from scientific principles....

Actually, Metric is no more scientific or accurate than Imperial - they are all just measurements after all. It is simply that they are calculated on Base 10, much like our numbering system, rather than other bases (used, admittedly, inconsistently). And the decision to do that,rather than "rationalise" on a Base 12 was taken in the French Revolutionary period so as a) to appear more "rational" and b) to differentiate the modern French from their primitive European enemies. And, before anyone brings up the old computer chestnut, it is quite possible to compute on £SD, cos I used to.
[And try talking to wood merchants - can i have two metres of 4x2 please]

 

[Wyvern]

Well if we're bringing computers into it we should be counting in hexadecimal.

 

[Old Timer]

The Metre was originally intended to be 1-10,000,000 of the distance on the earth's surface between the equator and either pole; however, because of errors in the original survey for determining the metre and because of the impracticality of referring to such a standard, the metre was later redefined in terms of the standard prepared and kept at Sèvres, France, near Paris.

Originally defined as the distance between two scratches on a bar of platinum-iridium alloy, in 1983 the metre was officially redefined as the distance traveled by light in vacuum during 1-299,792,458 of a second.

 

[EM2]

Slightly off topic, but I was in a builder's merchants a while ago, and the fellow next to me at the counter asked for six feet of copper pipe.
'Sorry sir, but it's sold in metric lengths now. Two metres is the nearest'
'OK, I'll have two metres'
'No problem. Half-inch or three quarter?'

 

[Wyvern]

A Yard is said to be the average distance between the tip of the nose and the longest finer of an outstretched arm.

A Chain is 22 yards, which is the length of a cricket pitch

There are 80 Chains to a mile.

And ten chains are one furlong

 

[Old Timer]

Slightly off topic, but I was in a builder's merchants a while ago, and the fellow next to me at the counter asked for six feet of copper pipe.
'Sorry sir, but it's sold in metric lengths now. Two metres is the nearest'
'OK, I'll have two metres'
'No problem. Half-inch or three quarter?'

Pity us on track renewals then !

The site is given in Miles and Chains normally "measured" from the nearest 1/4 mile post which can be out by as much as a 100 yards or more.

We then wheel out the correct start and finish mileages quoted, which is done from a defined reference point which inevtably means that the milesages shown in the Spec are out, so we then have to get a Variation instructed to the Spec, not the easiest thing in the world.

Having done this and marked up the Limits of Renewal, (LOR) our Techs used to come along and wheel it out in metres, which was then reconverted into "Metric Chains" for ground marking.

The design meanwhile was done in metres and converted as required.

That nonsense was one of the first things I stopped when I took over and everything within the LOR is done on metres now, at least on my patch !

Tamping design has to be produced in miles and yards however as does the input data relating to the track renewal, (except that certain data is entered in mm !) into Network Rail's database.

Track Renewals reporting to I&Is control centre, and within the I&I Project team, is done in Miles and chains.

OHL Design has been done in Km / metres for some time now however it uses a different reference point and so will have been wheeled out precisely as opposed to the track mileage which is converted. The outcome of this is that you can have one specific point which has two different metric distances, one for OHL and one for track.

Confused ?

If you weren't before then you will be now.

 

[Trog]

If you look carefully at the OHL gantry plates on the south end of the WCML you will often find that the last mast in a OHL mile is to the north of the next track milepost. As even though these masts were set out and numbered in imperial. The OHL used their own zero miles point at Euston, instead of using the existing mileage. Overlaid on this are errors where various mileposts have moved out of position over the years etc.
All good fun.

 

[Domeyhead]

If we're still using chains I'm amazed nobody has brought up the shed units of measurement as I suspect most of us years to spend more time in our sheds. Just as an overview the shed charter decreed its own SI units known collectively as The Furlong/Firkin/Fortnight (FFF) system.

Anyone who finds they can only truly enjoy Railway Magazine when surrounded by all the accumulated rubbish they promised their wife they had get rid of might enjoy this explanation:-
http://homepages.tesco.net/~scotsnet/o.f.carter/fun/fun319.htm

 

[Old Timer]

OHL 0 mileage starts at the extreme termination Structure so anomalies occur when starting at a terminal station, especially when the P. Way 0 is located in the middle of the platforms.

When WCRM was commenced a "standard" set of reference points were created from where all future distances and surveys were taken, which demonstrates that every cloud does have a silver lining, even if it didn't work out right at Rugby becuse of the way the Design Contractor surveyed it :roll::roll:

 

[SWT Driver]

QUE?

 

[Old Timer]

QUE?

In most instances mileages to stations are measured to the centre of the platforms, in other to the buffer stops.

Changes over the years may mean that the zero point is actually further out.

Now, when you start an Electrification Scheme, each Structure has to be numbered, logically starting from XX00/01. The problem therein of course is when track mileage Zero is in the middle of the station, or the Structure has to fall some way back behind zero.

Obviously because you cannot have a negative Structure number XX00/01 must start at the Termination Structure, therefore OHL and track mileages can sometimes fall out of line.

An example is the Up Birmingham at Rugby, where the two Birmingham lines diverge. On the Down Birmingham it is not a problem, but on the Up Birmingham line the Structure numbers are slightly different to the track mileage, particulalry as the route was surveyed from track middle (10 foot), so when the lines rejoin, the mileages for the Structures are different on the Down and the Up.