SCRCA Knowledge Base for Bridge SAC/66 - Ribblehead Viaduct

Submitted by mark.harvey / Tue, 14/02/2017 - 18:53
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At a glance (key statistics)

Location

OS Grid reference: SD 75940 79470.

Latitude: 54.21041 , Longitude: -2.370341000000053.).

Distance (rail-miles) from London St Pancras: 247 miles, 60 chains.

Date of construction 1870 to 1875. The first stone was laid (by William H. Ashwell) on October 12th, 1870. The first group of six arches were ‘turned’ in 1872.
Number of arches

24 arches, supported on 23 piers and 2 end abutments. Each arch has a rise of 18 feet. The span of the arches to the south of pier 14 is 43 feet at the springing course (measured along the viaduct's centre line). The span of the arches to the north of pier 14 is 45 feet.

Length Approximately one quarter of a mile or, more accurately 440 yards or, even more accurately 1,328 feet.
Maximum height above the ground

100 feet. (Some sources quote 104 feet, but the level of the ground surface has altered significantly since the viaduct was constructed. A number of secondary sources quote the height as being 118 feet. However, this almost certainly a misinterpretation of contemporary acccounts such as the following extract from the October 21st, 1871 edition of the Lancaster Guardian: "The depth from the rail level of the viaduct to the bottom of the deepest foundation will be, when finished, about 118 feet." )

Width

Approximately 34 feet across parapets. (The width varies slightly along the viaduct's length, probably to maintain clearance as the curvature alters).

Built for double track, but reduced to single track in 1984.

Pier thickness The normal piers are 13 feet thick at the base, but only 6 feet thick at the top. They have a 1 in 32 'bater' or taper on each face. The king piers are as twice as thick (26 feet at the base), so they give the structure extra strength and reduce the risk of a complete collapse in the unlikely event that one section should fail.
Gradient of trackbed 1 in 100 (so the north end is approximately 13 feet 3 inches higher than the south end).
Construction materials Limestone for piers, end abutments, voussoirs, external spandrels and parapets. Gritstone for parapet stringcourse and parapet copings. Engineering bricks for the arches. Track bed supported by flagstones spanning six sets of spandrels per arch.
First trains

On Sunday 6th September 1874, a contractor's train (hauled by the locomotive known as 'Diamond') became the first train to carry passengers across the viaduct.

In or around August, 1875, the first goods trains began to traverse the full Settle to Carlisle route. However, local goods trains operated along the two ends of the line well before this date.

On 1st May 1876, the first passenger train traversed the full Settle to Carlisle route.

Protection level Scheduled Ancient Monument. Grade II* Listed (List Entry Number 1132228). Located in the Yorkshire Dales National Park and the Settle-Carlisle Railway Conservation Area.

Additional information

  • According to the caption for plate 45 in Anderson, V.R. & Fox, G.K.: "Stations & structures of the Settle & Carlisle Railway" (Oxford Publishing Company, 1986), the exact length of the viaduct (and the total number of arches) was not decided until part-way through the construction process:

"it was not decided until December 1872 whether to have 24 or 18 arches."

  • However, Anderson & Fox do not provide details of the source of this information and it is contradicted by the following extracts from contemporary accounts:

Lancaster Guardian, July 23rd 1870:

"The foundations are being taken out at this moss for the large viaduct, which  will consist of 24 openings . . ."

Lancaster Guardian, October 21st, 1871:

"Batty Moss Viaduct, which is under the superintendence of Mr. Hurst, is an undertaking of considerable magnitude. This immense structure, when finished, will consist of twenty-four arches, each arch of 45 feet span and 18 feet rise."

  • The length of the viaduct was dictated by the need to balance:

    • the availability of stonemasons (to shape and lay the stone blocks used to construct the piers), and

    • the availability of labourers (to excavate, transport, tip and compact the rubble and boulder clay used to form the adjacent embankments).

  • Before the viaduct's piers could be constructed, holes up to 25 feet deep were dug through the peat and boulder clay to reach the limestone bedrock beneath. To provide a firm foundation for the piers, concrete was then poured into these holes up to a depth of approximately six feet.
  • The viaduct contains over 30,000 cubic yards of 'black' limestone, the bulk of which was quarried from a carefully selected site beneath and beside a stream in Little Dale (about 1½ miles north of the viaduct). The engineers were determined to find the best possible stone and, in order to gain access to the rock beds that lay beneath the stream itself, they had to divert the stream in an asphalt-lined stone trough.
  • The external faces of the piers are constructed from limestone blocks of varying sizes, as are the voussoirs, external spandrels and parapet walls. The largest stones used weigh between four and five tons each. Steam-operated lifting gear (mounted on temporary wooden scaffolding) was used to lift these enormous stones into place.
  • The piers were constructed from north-west to south-east. However, they are numbered in the opposite direction. Pier 1 is located at the south-east end, pier 2 is in the middle and pier 23 is at the north-west end.
  • The arches were built in self-supporting sets of six (starting from north end), with wider 'king piers' marking the transition from one set to the next. When constructed, the king piers and end-abutments were hollow, but strengthened with internal walls constructed from limestone blocks. However, the voids have since been filled to prevent water-ingress.
  • The arches were built around wooden formers (frames) supported by scaffolding, which was in turn supported by two rows of projecting stone blocks in the piers. (The latter are still visible today.)
  • The arches are formed from multiple layers of brick and they vary in thickness from 3’ 0” at the springing point (on top of the piers), to 2’ 3” at the crown (i.e. the apex of the arch). The bricks used were made on-site (in a temporary brickworks) from locally extracted clay. They were of very variable quality and rejected bricks can still be seen littering the ground in many parts of the site.
  • There was intense commercial pressure to open the line to traffic as quickly as possible. These pressures were so great that goods trains began to operate across the viaduct before the parapet walls had been fully constructed.
  • The average wage paid to the workers building the viaduct was between 1s and 1s & 6d per day. The masons were paid 6s & 6d per day and they went on strike for over a week in 1872 when their working day was extended from nine to ten hours. Due to the severity of the working and living conditions, there was a high staff turnover and this was particularly noticeable immediately after each pay day.
  • The viaduct is built on a slight curve. (One source states that the radius of this curve is about one mile, although this has not yet been confirmed.)
  • A large datestone bearing the number '1875' is set into the eastern parapet wall above pier number 12 (the central king pier). This datestone records the year that construction work on the viaduct ended and the numbers were picked-out in gold leaf during rennovation works in the early 1990s. A similar stone is set into the western parapet wall, but the date is facing inwards (towards the tracks). The carved number '5' is damaged and barely legible. It is possible (perhaps even likely) that the stone was deliberately installed facing the 'wrong' way to avoid the time and expense of carving a replacement.
  • It has been estimated that approximately 250,000 tonnes of rock and clay were used in the construction of the embankments at the north and south ends of the viaduct, all of which had to be transported from nearby cuttings.
  • For a fascinating set of contemporary accounts relating to the construction of the viaduct, see paragraphs 1.19 to 1.34 of "How they built the Settle-Carlisle railway: C - Contract 1."
  • The winter winds swirl around the lofty piers of the viaduct with incredible force and speeds as high as 90mph. At times, railway workers trying to walk across the viaduct have been forced to get down on their hands and knees to prevent themselves being blown over. Railway folklore tells of a track ganger who, whilst walking across the viaduct on a particularly windy day, had his cap blown from his head. According to the story, the swirling wind whisked the cap down one side of the viaduct, through one of the arches, up the other side and deposited it firmly back on top of the man's head - albeit back to front. Unfortunately, the story is almost certainly just that as the parapet wall tends to deflect the wind upwards so that it passes well above the head (and hats) height of even the tallest of railway workers. However, there are numerous true accounts of tarpaulins being blown off goods wagons as they crossed the viaduct and, during a storm in 1966, at least six cars were blown completely off the transporter wagons of a northbound frieght train. They landed on the 'Up' track but, fortunately, all trains were stopped before a collision occurred.
  • A number of sources state that members of the local Home Guard were assigned to guard the viaduct against possible German invasion during the Second World War.
  • The viaduct has always required constant maintenance and, in the 1980s, old steel rails and concrete cladding were used to strengthen many of the piers that had become weakened by water ingress. As a safety precaution, the line across the viaduct was singled until repairs could be carried out. Trial borings were made into some piers and minor repairs were carried-out in 1988. A waterproof membrane was added in 1989 and major restoration work was carried out between 1990-1992.
  • Although the rennovation works were carried-out to a high standard, the original double track formation was not reinstated and the viaduct remains the only stretch of single track between Settle Junction and Petteril Bridge Junction.
  • While Ribblehead Viaduct is the longest viaduct on the Settle-Carlisle line, it is not the tallest. That honour rests with the 130 foot tall Smardale Viaduct (SCRCA Structure 268670).

The best place to appreciate the sheer scale of the viaduct is beside the stone cairn / memorial located close to the base of the central pier (pier 12). WARNING: Do not linger underneath the viaduct as there is a constant danger of falling masonry. This is because the weather is constantly attacking the stone blocks and brickwork, not because the viaduct is in a poor state of repair.

Further reading

For an authoritative account of this iconic structure and its renovation, see Freschini, Tony: "A Brief Guide to Ribblehead Viaduct" (FoSCL, 2007).

An interesting illustrated account can also be found in W.R. Mitchell: "Ribblehead Re-born" (Castleberg, 1992).

Acknowledgements

Knowledge base compiled by and © Mark R. Harvey.