Railway distances

[cyclebytrain]

Well I think they're different ways of measuring something for a different purpose. If I have 4 help points that should be located equally along a 108m (or 6 car) platform it wouldn't be very accurate (or wise!) to say that the help points should be placed one and a half cars apart.

That's exactly my point -you use the suitable unit of measurement for the information you're trying to convey. Be it metric, imperial or a local empirical measure e.g. "half way down the platform"

 

[ralphchadkirk]

I think you're a bit confused here. In the example, you are measuring a distance along a platform. You could do it in metres, or in carriages. Both are valid, even if you don't like it.

I think you are confused. Carriages have never and never will be a valid unit of measurement.

 

[cyclebytrain]

Not in the slightest I'm afraid. Ask someone the walk 2 carriages down a train and you'll see that they can manage it easily.

 

[Old Timer]

Are signals placed at exctact chainages then? If the distant is a sempahore then the Inner Home signal can be placed 440 yards (20 chains) in advance of the Home signal as this is the clearing point distance. If the distant is a colour light however the this is 200 yards (9.09 chains). In this case would the signal actually get placed at 10 chains rather than 200 yards?

Signals are placed at the exact distances as far as possible, although they can be placed slightly further out if local ground conditions dictate.

Railways were built using chains, as the chain was a historically common form of distance measurement in Great Britain at the time.

Just before I left, all new works design was being undertaken in metres, using a pre-determined datum point.

Currently I still believe that alterations to signals are quoted in yards within Section C notices.

I believe it is still the case that the Yellow commissioning plans issued to Operating staff still show the distances in miles and yards.

Calculated braking distances for track renewals temporary speed restrictions are done in yards and are converted to chains to go into the Weekly Operating Notice.

 

[ralphchadkirk]

Not in the slightest I'm afraid. Ask someone the walk 2 carriages down a train and you'll see that they can manage it easily.

SO why has a carriage never been an SI unit of measurement? Yet imperial and metric both have. I'm all for picking the most useful unit (metric or imperial) for the job, but there are limits. Carriages differ in length. It would be silly to say build a wall 50 paving slabs long wouldn't it? Yet feet or metres would be fine. There's no point making units of measurement up when there are perfectly good systems already.

 

[Mojo]

Not sure where you got this information from old chap but I regret to say it is incorrect.

The metric system was developed in France under the leadership of Louis XVI, and principally a Frenchman called Antoine-Laurent de Lavoisier, in the late 18th Century.

British scientists have worked on developing the metric system since it signed the Metre convention in 1884.

The first person on record for proposing a decimal system of measurement was John Wilkins in the 17th century. But SI was initially developed in France; no reason to reject a system in favour of one which also makes sense!

Despite your views on the Imperial system, like the rest of the world, it was based upon units derived from measurements associated with the body, and all the important historic buildings were built using these systems worldwide.

The problem is, the Imperial "system" isn't really a system at all. The length of many of the measurements differs between countries.

If the foot is in some way representative of the human body I must be missing it, it would make the average shoe size to be 12½! I believe the unit of length ''feet'' is Roman!

Remembering Imperial is easy too, as 22 yards (the length of a cricket pitch), is one chain, 80 chains are in a mile

I can't imagine myself remembering all those measurements nor doing simple calculations with them!

 

[Old Timer]

I can't imagine myself remembering all those measurements nor doing simple calculations with them!

Well we had to at school, and without the aid of calculators !

We used to do technical drawings in fractions of an inch, creating a drawing frame on a blank piece of paper, and scaling down objects from feet !

That is a skill totally lost today as people are unable even to know how to square off a piece of paper, and if you asked them to do a three dimensional drawing from a plan view with a pencil, a ruler and a set square they would look at you as if you had just stepped off a spacecraft.

 

[Mojo]

I had to confess to Googling that, but I can do it, I just don't think I've heard that term before!

Back on topic I would be interested to know exactly how when setting out TSRs or anything else how the measurements are done. Are they taken from a milepost and are things like wheels used to work out the distance?

 

[cyclebytrain]

Well it's never been an SI unit primarily because it's not an SI unit. It is a local empirical unit of distance and where it's used it's usually more useful than using either an SI or an imperial unit of distance.

I'm afraid you're argument about not building a wall an integer multiple of slabs (or blocks) is a bit flawed as well. Frequently the dimensions of a wall aren't so critical as to require cutting a block and in those cases the wall is indeed constructed based on a number of blocks because it's cheaper than cutting blocks...

 

[ralphchadkirk]

Well it's never been an SI unit primarily because it's not an SI unit. It is a local empirical unit of distance and where it's used it's usually more useful than using either an SI or an imperial unit of distance.

I'm afraid you're argument about not building a wall an integer multiple of slabs (or blocks) is a bit flawed as well. Frequently the dimensions of a wall aren't so critical as to require cutting a block and in those cases the wall is indeed constructed based on a number of blocks because it's cheaper than cutting blocks...

I think I'd, and most people, would be very annoyed if you had asked a builder to build a wall 3 metres long and he built it 3.5 metres long because his bricks fitted it :roll:
I would also like to think that the dimensions of my house walls are rather important, as they are holding the roof up :roll:

 

[Old Timer]

...Back on topic I would be interested to know exactly how when setting out TSRs or anything else how the measurements are done. Are they taken from a milepost and are things like wheels used to work out the distance?

Ahhh, this of course is the difference between Track Renewals and Maintenance !

Maintenance people will look to the nearest 1/4 post and stick the equipment down as close to an access point as possible.

Track renewals staff however are given (at least in my previous Companies) a layout plan showing how far from the 1/4 post, and the position of that will have been referenced.

Complaints about track renewals TSRs are very rare indeed, compared to maintenance TSRs. Sorry any Mtce chaps here, but you know I am right deep down in your hearts ! .

The critical factor to be aware of here, is that mile posts and especially 1/4 mile posts are not accurately spaced. People think they are but they can be up to 100 yards, sometimes more, out !

That is why we use a datum reference point on track renewals

 

[cyclebytrain]

Well we had to at school, and without the aid of calculators !

We used to do technical drawings in fractions of an inch, creating a drawing frame on a blank piece of paper, and scaling down objects from feet !

That is a skill totally lost today as people are unable even to know how to square off a piece of paper, and if you asked them to do a three dimensional drawing from a plan view with a pencil, a ruler and a set square they would look at you as if you had just stepped off a spacecraft.

Despite knowing how, I'd give you that sort of look (or worse) -God did not intend me to be a draughtsman (or if he did he made a right hash of it!
But I agree entirely, I come across a lot of people can't who haven't ever had to do it can't as a consequence don't properly understand what the drawing is telling them (Personally I find it easier to do a quick mental check with Imperial units than Metric ones, but that might just be because I'm old fashioned...)
--- old post above --- --- new post below ---

I think I'd, and most people, would be very annoyed if you had asked a builder to build a wall 3 metres long and he built it 3.5 metres long because his bricks fitted it :roll:
I would also like to think that the dimensions of my house walls are rather important, as they are holding the roof up :roll:

But would you be very upset if it was an inch longer or shorter -the more precisely you specify, the more you will pay for it.

 

[Trog]

Are you joking? The number of carriages going somewhere is not a unit of measurement. Hence why it wouldn't be measured in feet, yards, metres, centimetres or chains.

Which is rather strange as the number of 10'-0" wheel base coal wagons is a measurement of length.

Most sidings and freight trains being measured in a unit called a SLU (Standard Length Unit), a SLU being 21'-0" or the length of a traditional four wheeled coal wagon.
--- old post above --- --- new post below ---

The critical factor to be aware of here, is that mile posts and especially 1/4 mile posts are not accurately spaced.

The mileposts in some places are also being affected by metrification. The space between the miles being marked out in meters. When a milepost is replaced the new post is erected at a multilple of 1600m past the post they started wheeling from, which gives an error of about 10 yards per mile. As they are usually too lazy to remove the old post. You then have to know to use the old post made of rail and ignore the shiny new one. :roll:

That is why we use a datum reference point on track renewals

I always described the job in narrative as well as mileage. Start after the last F40 sleeper at XXX and finish four sleepers into the F27BS sleepers at YYY. Using the four displaced sleepers to replace the adjustment switch timbers at ZZZ. Its a shame most re-layers these days can't read.

Back when I was a lad relaying jobs were measured out to the nearest 1/4" using a tape measure and track square, none of this decadent wheeling it out to the nearest meter.


TQ.

Job finishes 1m inside a level crossing, suggest shortening the job by 17m to avoid level crossing.

A. (As thought but not sent for diplomatic reasons)

Read section I you w****r it explains that those Alphatek coated rails (you know the grey ones) in that little bit of Cat2 on the end of the job are to run through the level crossing and finish just beyond the crossing.

(As it will be relatively cheap and easy for you to replace the rails through the crossing while you have the crossing up for the stressing. Rather than have the maintainers come round and lift it all again in six months time, just to change two 60'-0"'s.)

Mumble mumble back in my young day..... 48hr shift.... no lunch break....
up hill both ways... thankful for it...... c**p behind gorse bush.... three feet of snow... ballast minutes not printed on soft paper.... risk of arsenick poisioning.... mumble mumble .. don't know they are born....

 

[Old Timer]

..The mileposts in some places are also being affected by metrification. The space between the miles being marked out in meters. When a milepost is replaced the new post is erected at a multilple of 1600m past the post they started wheeling from, which gives an error of about 10 yards per mile. As they are usually too lazy to remove the old post. You then have to know to use the old post made of rail and ignore the shiny new one. :roll:....

Thanks for the update on that, chap. Appreciated.

...I always described the job in narrative as well as mileage. Start after the last F40 sleeper at XXX and finish four sleepers into the F27BS sleepers at YYY. Using the four displaced sleepers to replace the adjustment switch timbers at ZZZ. Its a shame most re-layers these days can't read. ad:

Back when I was a lad relaying jobs were measured out to the nearest 1/4" using a tape measure and track square, none of this decadent wheeling it out to the nearest meter.....

When I took over a relaying section several years ago, I discovered that they were using 1/4 posts, and wheeling the job out, whereas the Maintainer just guessed where the job started and finished. About the time I took over, a big fuss was starting over alleged "irregularities" in claims made for renewals lengths.

It transpired that the Track Renewals Engineer's staff had wheeled from the datum point to the start of the job, the Maintenance Manager's staff simply guessed where the LOR were, and the distance, whereas the track renewals team wheeled from the nearest 1/4mp. Of course all these distances were different, but even though the length was done, we were only paid for the section inside the datum point referenced mileages.

I also discovered the mythical decimal chain :roll: :roll: :roll: :roll: which required various conversions and with rounding up represented a substantial difference over a long relay.

I immediately directed that we used metric entirely within renewals, and we wheeled from the datum point.

Of course as you will know that created massive problems in adjusting the workbank data, and moreso when we discovered that a 40 chain relay was more like a 45 chain relay.

......Mumble mumble back in my young day..... 48hr shift.... no lunch break....up hill both ways... thankful for it...... c**p behind gorse bush.... three feet of snow... ballast minutes not printed on soft paper.... risk of arsenick poisioning.... mumble mumble .. don't know they are born....

To be honest chap, these guys these days whinge if they are not provided with gentle toilet paper and fragrance handwash. They don't believe stories of drinking warm tea "flavoured" with diesel on a big derailment site - and being glad to do so because you have been out there for long hours.

It gets even better because I heard a story of S&T Testing staff complaining that their three course dinners were outside the standard dinner allowance, and one wanting feather pillows ! :roll: :roll:

Anyway, talking of which, I am away to breakfast !

 

[Hydro]

Complaints about track renewals TSRs are very rare indeed, compared to maintenance TSRs. Sorry any Mtce chaps here, but you know I am right deep down in your hearts !

You want to try lugging a metal mickey half a mile from an access?



Maintenance TSR's aren't always awful. ESR's however...

 

[Zoe]

You want to try lugging a metal mickey half a mile from an access?

It may well want to exterminate you by the time it gets there.

 

[Hydro]

I wanted to exterminate the bloody thing. Possibly the most awkward object to carry, ever.


Using chainages is ok for rough distance work, but it's hardly accurate. When I worked with the Technical staff, all distances were wheeled out in metres for structure gauging and actual offsets and datums were in mm. Renewals walk outs were all done in metres, big stress jobs were all in metres. The more technical you got, it seemed the more metric and accurate you got. PWay work was all feet and inches, chainsawing bearers up, "sticking a 60 foot in" (oooer missus), all that malarkey.

 

[Ploughman]

I used to check the specifications that came to our renewals office.
This entailed going through the site and verifying total lengths and features and where the specification had its datum mile post.
I used to always wheel the site and include an overlap into existing of at least 200 metres to allow for disturbance to track through tamping and stressing.
The amount of times that I went to a site and the specified milepost did not actually exist was quite considerable.
Or as happened more than once I found the specified milepost but the survey crews from other contractors did not and again guessed the location from other features.
I did get one NWR bod to confess that the compiler had not actually visited the site just took a renewal prop and reworded it and guessed a milepost.
What used to annoy me was when renewing both tracks of a double track section and the reference mileposts in the specifications were different. This meant that the location of joints that may lay right opposite each other were, in one instance, as a matter of record 40 yards apart on paper.

 

[Hydro]

I'm forever travelling lines and areas that have an incredible amount of missing mileposts. Great when you're trying to sync a track recording vehicle with them at 90mph. I'm sure a few colleagues have felt like screaming "SORT YOUR MILEPOSTS OUT" when challenged about their defect reporting.

As a brief aside, 4 foot of bullhead stuck in an overgrown cess that was painted yellow in 1957 is a poor excuse for a 60 peg. Gripe over.

 

[miikey]

Some things are stated in Miles and Yards and some things are stated in Miles and Chains. There is no real standard to specify what you should write it as. I've written it in both formats and its accepted.