Highest numbered milepost in UK?

[matchmaker]

There always used to be two sets into York, with the GN mileage continuing on the east side of the line north of Chaloners Whin and the NER series starting from York on the west side. At some stage after the opening of the Selby Deviation they were changed, the NER posts being removed north of Colton Jn and the official measurement into York for all four lines being the GN sequence from King's Cross.

Sorry — posted without seeing the point had already been made!

The Scottish regional boundary is officially at Marshall Meadows.

 

[Bevan Price]

On the other end of the scale, I'm sure London Euston is mile post -0.03

When I'm out and about on the railways, I do find mileage posts interesting and tend to look out for them. The blue ones in the south west area are easy to spot. Some lines they are totally missing

Down south the most changes of mileages, seem to occur on the line from London Marylebone to Banbury.

I've always wondered just how accurate mile posts are.

Variable. Some seem to be fairly accurate, but others can be wildly inaccurate. Sometimes this may be carelessness when replacing "missing" mileposts, at other times the original measurements might be incorrect. Did the Victorian railway builders use actual physical chains to do measurements - if so, maybe there was poor quality control in manufacture, and they were not all identical.

The ex-LSWR mileposts from London Waterloo to Exeter get steadily less accurate all the way to Exeter.

And there is a very curious anomaly at Exeter, between Cowley Bridge Jn & Exeter St. David's Jn, that can still be seen in Quail.
The GWR mileages for these locations are 192m 52c & 194m 00c from Paddington (Difference 1m 28c.)
But the SR/LSWR mileages are 173m 50c & 172m 04c from Waterloo (Difference 1m 46c)
How can one explain a 18c difference between two measurements for exactly the same length of track ?

 

[Bevan Price]

Is that because the pre-grouping railway companies had different starting points, such that, for instance although it must be about 270 miles from Stanley Junction to Wick, the Highland Railway measured all their distances from Inverness?

The Far North HR series restarted at Inverness. South of there, the series zero is at Perth (rather than the former Stanley Jn)
And Forres to Inverness also has Perth as the zero point, measured via the older, now closed, route from Aviemore to Forres via Dava.

 

[HaggisBotherer]

Out of interest, are Wick and Thurso both measured from (I assume) Inverness? Or does one branch reset to zero at Georgemas Junction?

 

[Bevan Price]

Out of interest, are Wick and Thurso both measured from (I assume) Inverness? Or does one branch reset to zero at Georgemas Junction?

The Thurso branch has a zero at Georgemas Jn (147m 20c from Inverness.)
This is common practice at junctions where a reversal is required to access a branch, and the zero is at the points rather than a station. (Although re-posting may not take place if the points are relocated during track alterations).
Inevitably, there are exceptions. For example the GE/GN joint line (March - Lincoln/Doncaster) mileage started at Huntington and included a reversal at St. Ives.

 

[Senex]

The Thurso branch has a zero at Georgemas Jn (147m 20c from Inverness.)
This is common practice at junctions where a reversal is required to access a branch, and the zero is at the points rather than a station. (Although re-posting may not take place if the points are relocated during track alterations).
Inevitably, there are exceptions. For example the GE/GN joint line (March - Lincoln/Doncaster) mileage started at Huntington and included a reversal at St. Ives.

And, of course, there is a reversal at Carstairs for the mileposts of the Caledonian main line to Edinburgh.
The principle of the Midland re-mileposting in the first decade of the last century was that the posts always followed through on the shortest direct route from London St Pancras if there were a through route available. Trailing junctions always involved a new zero-post. Thus the long sequence to Petteril Bridge Jn runs via Leicester, Trent, Tapton Jn, Masborough, and the Whitehall Curve to the Settle & Carlisle Line. The Nottingham Loop ran through continuing the London series from Glendon Jn, Manton Jn, Melton Jn, Nottingham, and then on to Trowell Jn where it ended as the more direct figures from London were picked up. The Manchester line continued the London series from Trent Jn via Spondon Jn and Derby North Jn and onwards. IIRC this had 168½ miles at Chinley North Jn where there was also a 174 post running from London via Trent, Tapton Jn, Dronfield, and the Dore South Curve. The shorter distance continued from Chinley North Jn. And so on. How many other companies were quite so systematic? The only one I can think of is the NER, which re-mileposted about the same time. Maybe the Caledonian too?

 

[lewisf]

Are Irish rail distances in Km or miles?

Irish Rail still use mileposts and speed limits are still in mph despite the road network there switching to metric in 2005

 

[Senex]

The Scottish regional boundary is officially at Marshall Meadows.

When did the change of milepposts at Marshall Meadows come about? Pre-Grouping the NBR and the NER met in Berwick station.

 

[DelW]

Variable. Some seem to be fairly accurate, but others can be wildly inaccurate. Sometimes this may be carelessness when replacing "missing" mileposts, at other times the original measurements might be incorrect. Did the Victorian railway builders use actual physical chains to do measurements - if so, maybe there was poor quality control in manufacture, and they were not all identical.

Until the arrival of electronic systems in the 1970s, physical chains (or steel tapes) were the only means of accurate distance measurement. Even the Ordnance Survey's triangulation survey of Britain was based on a baseline west of London which had been measured as accurately as possible by physical chains. Of course there's always the possibility of operator error, or incorrect application of correction factors for temperature, gradient, tension, sag, etc.
The Victorian railway surveyors would have been able to tie their centrelines into the OS national grid, but I think it would have been simpler to physically measure the route chainages on the ground than to calculate them from national grid co-ordinates, especially when such calculations would all have been done by hand with 7-figure log tables. We still calculated setting-out for roads and bridges that way in the early 1970s, before electronic calculators were widely available.

And there is a very curious anomaly at Exeter, between Cowley Bridge Jn & Exeter St. David's Jn, that can still be seen in Quail.
The GWR mileages for these locations are 192m 52c & 194m 00c from Paddington (Difference 1m 28c.)
But the SR/LSWR mileages are 173m 50c & 172m 04c from Waterloo (Difference 1m 46c)
How can one explain a 18c difference between two measurements for exactly the same length of track ?

I don't know (and I don't have Quail to hand), but I'd guess that most probably GWR and LSWR used different datum points at one or both locations, e.g. mid-points of different platforms?

 

[pdeaves]

I don't know (and I don't have Quail to hand), but I'd guess that most probably GWR and LSWR used different datum points at one or both locations, e.g. mid-points of different platforms?

I don't think that would make an 18ch (nearly 1/4 mile) difference in the length between two junctions. Rather, I suspect (but don't know) that it arose from a special access fee. Fares, goods fees and track access on 'other' railways were calculated on a mileage basis but adjustments were added in as appropriate/agreed. I have a Victorian document for places in northern England and Scotland that declares that whilst the mileage between X and Y is a certain figure, rates should be calculated on another (higher) figure. Presumably this arrangement was to help pay the capital cost of some expensive feature; maybe a similar arrangement existed at Exeter and the LSWR allowed for it in its mileages.

 

[DelW]

I don't think that would make an 18ch (nearly 1/4 mile) difference in the length between two junctions.

Oops, I'd missed that Bevan was referring to St David's junction, not the station . As you say, not easy to lose or gain 18c between two junctions.

I hadn't ever heard of using amended mileages to adjust payments. An early version of Mr Trump's "alternative facts"?

 

[Senex]

I have a Victorian document for places in northern England and Scotland that declares that whilst the mileage between X and Y is a certain figure, rates should be calculated on another (higher) figure. Presumably this arrangement was to help pay the capital cost of some expensive feature; maybe a similar arrangement existed at Exeter and the LSWR allowed for it in its mileages.

There were quite a few of these special allowances, but as far as I know the only LSW one was the Tamar Bridge at Calstock where the actual distance of 19 chains was allowed to be charged as 3.5 miles.

 

[etr221]

Until the arrival of electronic systems in the 1970s, physical chains (or steel tapes) were the only means of accurate distance measurement. Even the Ordnance Survey's triangulation survey of Britain was based on a baseline west of London which had been measured as accurately as possible by physical chains.

To be accurate, ten feet long glass rods. Modern surveying techniques (satellite based) have shown it to be remarkably accurate (and remember we're talking about a mile, to within a very small fraction of an inch)

Of course there's always the possibility of operator error, or incorrect application of correction factors for temperature, gradient, tension, sag, etc.
The Victorian railway surveyors would have been able to tie their centrelines into the OS national grid,

In a word, no. The OS did not complete its national one inch survey until mid-Victorian times, and large scale mapping only at the end of the 19th century. So many of the early railway surveyors did not have OS maps - they were starting from not much more than a blank sheet of paper, or a variety of 'local' maps with varied standards. And even the Ordnance Survey only adopted a standard national projection and datum (OSGB36) - and so the National Grid - in the late thirties, and it wasn't released to the public until after the war, in late 1945.

but I think it would have been simpler to physically measure the route chainages on the ground than to calculate them from national grid co-ordinates, especially when such calculations would all have been done by hand with 7-figure log tables. We still calculated setting-out for roads and bridges that way in the early 1970s, before electronic calculators were widely available.

So, yes, I'm sure chainages would have been physically measured out - not a a task to be undertaken lightly. And where mile-posts were changed, as on (e.g.) the Midland, the new ones would be based on the old ones, and errors - even where known (hence the various 'long' and 'short' miles on the system) - and discrepancies due to realignment would have continued. Or to put it more simply, if you want to be precise, mileposts are an indication of position, not of distance.

 

[LNW-GW Joint]

I hadn't ever heard of using amended mileages to adjust payments. An early version of Mr Trump's "alternative facts"?

The one often quoted is the mileage to Liverpool.
The 1869 cut-off from Weaver Jn to Edge Hill via Runcorn charged the same rates as the 8 miles longer original (1838) route via Earlestown.
This was supposedly to pay for the bridge/viaduct over the Mersey, in effect a toll.
You can still see things like that today, with higher fares for SE services via HS1.
Meanwhile, the motorway system has just abolished the tolls on the Severn crossing (after 52 years).

 

[DelW]

To be accurate, ten feet long glass rods. Modern surveying techniques (satellite based) have shown it to be remarkably accurate (and remember we're talking about a mile, to within a very small fraction of an inch)

Ah, you're right, it's a while since I read the history, I should have just said physical means. It's actually much more than a mile, between just north of Heathrow and Hampton on Thames, 5.19 miles according to the OS website. Which of course makes it even more of an achievement!

In a word, no. The OS did not complete its national one inch survey until mid-Victorian times, and large scale mapping only at the end of the 19th century. So many of the early railway surveyors did not have OS maps - they were starting from not much more than a blank sheet of paper, or a variety of 'local' maps with varied standards. And even the Ordnance Survey only adopted a standard national projection and datum (OSGB36) - and so the National Grid - in the late thirties, and it wasn't released to the public until after the war, in late 1945.

The original triangulations were well under way, if not complete, by the start of the railway era. Although printed maps only became available progressively between 1801 and 1870, I would have thought that professional railway surveyors might have had access to OS's co-ordinates for those markers that were still visible. However that's pure guesswork and may be completely wrong, it may be my background in using grid co-ordinates for roads and bridges that leads me to assume it was similar in that era. The triangulations must have used some early form of projection, and projections have been progressively refined ever since, including new versions in the GPS era. I have read about those some while ago, and IIRC it gets pretty complex.

So, yes, I'm sure chainages would have been physically measured out - not a a task to be undertaken lightly. And where mile-posts were changed, as on (e.g.) the Midland, the new ones would be based on the old ones, and errors - even where known (hence the various 'long' and 'short' miles on the system) - and discrepancies due to realignment would have continued. Or to put it more simply, if you want to be precise, mileposts are an indication of position, not of distance.

Agreed

 

[Senex]

So, yes, I'm sure chainages would have been physically measured out - not a a task to be undertaken lightly. And where mile-posts were changed, as on (e.g.) the Midland, the new ones would be based on the old ones, and errors - even where known (hence the various 'long' and 'short' miles on the system) - and discrepancies due to realignment would have continued. Or to put it more simply, if you want to be precise, mileposts are an indication of position, not of distance.

I think the Midland did actually re-measure the line, and more than once during the company's existence. There's certainly a record of £85 being spent in the early 1890s on equipping a van with measuring apparatus in preparation for making a new set of the company's distance diagrams, and the complete new set of distances was "published" in 1893.

 

[etr221]

Ah, you're right, it's a while since I read the history, I should have just said physical means. It's actually much more than a mile, between just north of Heathrow and Hampton on Thames, 5.19 miles according to the OS website. Which of course makes it even more of an achievement!

The original triangulations were well under way, if not complete, by the start of the railway era. Although printed maps only became available progressively between 1801 and 1870, I would have thought that professional railway surveyors might have had access to OS's co-ordinates for those markers that were still visible. However that's pure guesswork and may be completely wrong, it may be my background in using grid co-ordinates for roads and bridges that leads me to assume it was similar in that era. The triangulations must have used some early form of projection, and projections have been progressively refined ever since, including new versions in the GPS era. I have read about those some while ago, and IIRC it gets pretty complex.

As you say, it gets complex - I might say very rather than pretty.

My conception is that early railway surveyors were in a completely different era, and probably just laying out railways from 'here' (somewhere in Stockton) to 'there' (somewhere in Darlington), with any reference system or drawings being internal to the railway. Any sort of relating them to a national system - or there even being one - was for the future. I would suggest that it was more like how you might put some tracks down in the garden as a toy, than any (let alone all) of the detail involved these days in HS2, etc. The OS probably only got involved when their surveyors turned up to put it on the map!

And even at the end of the Victorian era, I think it was more a matter of just drawing lines on the map, and looking to see where that meant on the ground, than anything more sophisticated.

I don't know what sort of system the OS had internally for knowing and recording what was where, but I don't believe they had any sort of 'public' reference system (beyond lat and long) until between the wars. (It was only during WW1 that the Army systematically adopted any sort of reference system, beyond names (and initially it was individual map based), and that was rather evolution through need, trial and error, than any sort of formal design)

 

[LNW-GW Joint]

The Tithe Maps (1836-c1851) provided one of the earliest mapping resources for England and Wales.
Their purpose was to identify the ownership and occupation of land subject to tithes (by no means all the land, as some areas were exempt from tithes).
This article describes the process of mapping, and where the maps are held.
https://en.wikipedia.org/wiki/Tithe_map

The maps and schedules held by the commissioners passed to the Inland Revenue (the predecessors of HMRC) and are now held in The National Archives at Kew[7] (classes IR29 and IR30). In a partnership with The National Archives[8] and a family history data website, TheGenealogist, it is possible to search the apportionments and view tithe maps.[9] The black and white maps and apportionments that are online cover all that are available for England and Wales while there is an ongoing project by TheGenealogist to scan the originals in colour, some of which they have already made available.[10]

Most of the extant parish copies are now held at the county record offices. The diocesan copies for most Welsh parishes are held in the National Library of Wales at Aberystwyth. Prior to the publication of large scale Ordnance Survey maps in the late 19th century, tithe maps were frequently copied (in whole or part) for other purposes: for example in connection with planned railways, or as part of the title deeds transferred on a sale of land. More recently, tithe maps and apportionments have often been used for reference by genealogists and other historical researchers. For many parishes they provide the only large scale map showing the landscape prior to the Industrial Revolution,[11] and they frequently provide the earliest evidence for the field system in the parish

By chance, the tithe maps were created in the early period of railway building, in the mid-1830s.
Civil registration, detailed population censuses and local government reorganisation also happened about this time, all stemming from the Great Reform Act of 1832.
In Cheshire, where my family comes from so I have a personal interest, you can see the tithe maps on line at http://maps.cheshire.gov.uk/tithemaps/
This is in an era where the Grand Junction, Manchester & Birmingham and Chester & Crewe railways were built across the county.
It's quite likely that these were the most detailed maps available to the early railway builders.

This is a link to the tithe map for Basford, Crewe, dated c1841. http://maps.cheshire.gov.uk/tithemaps/TwinMaps.aspx?township=EDT_41-2
It shows the Grand Junction Railway passing close alongside Basford Hall (now demolished), and the ownership of the adjacent property.
A modern OS map of the same area is shown alongside (and you can view different OS maps from the intervening years).
If you drag the modern map down a bit, Crewe station emerges (the tithe map is dated 1840, before the Manchester line opened).
At that time you can see that the site of the GJR station was completely north of the Nantwich Road bridge, opposite the Crewe Arms.
Crewe North Junction was then set among fields in all three directions!
I suspect that maps like these were the best that Messrs Locke, Stephenson and Rastrick had to plan their lines.

 

[adrock1976]

On the sideways discussion about Ordnance Survey mapping, for land elevation, was the zero reference point the Victoria Dock in Liverpool?

 

[etr221]

On the sideways discussion about Ordnance Survey mapping, for land elevation, was the zero reference point the Victoria Dock in Liverpool?

From 1844 to 1921, yes (at least for England and Wales), see https://www.ordnancesurvey.co.uk/gps/legacy-control-information/liverpool-to-newlyn . From that it implies that, prior to 1840, the OS did not have a height datum.

 

[hexagon789]

There should be a 326 MP approaching Penzance which would be in with a good shout.

According to the Railway Performance Society, 326.5 miles at Penzance is the highest numbered milepost in Great Britain.