The High Level Bridge is a road and railway bridge spanning the River Tyne between Newcastle upon Tyne and Gateshead in North East England. It was built by the Hawks familyOxford Dictionary of National Biography: Hawks family from 5,050tons of iron. George Hawks, Mayor of Gateshead, drove in the last key of the structure on 7 June 1849, and the bridge was officially opened by Queen Victoria later that year.

It was designed by Robert Stephenson to form a rail link towards Scotland for the developing English railway network; a carriageway for road vehicles and pedestrians was incorporated to generate additional revenue. The main structural elements are tied cast-iron arches.

It continues to carry rail traffic, although the King Edward bridge nearby was opened in 1906 to ease congestion. The roadway is also still in use, with a weight restriction. It is a Grade I listed structure.

First bridge proposals

The Newcastle-upon-Tyne and Carlisle Railway Act 1835 (5 & 6 Will. 4. c. xxxi) authorised the Newcastle and Carlisle Railway (N&CR) to approach Newcastle to a terminus at Redheugh, on the south bank of the River Tyne, close to the end of the present-day New Redheugh Bridge. The act also authorised a crossing of the Tyne there, giving rail access to the north shore quays. The river was shallow at this point, and the bridge would have been at a low level, only above high water. The line would then have climbed to a terminus at the Spital, near Neville Street and the east end of the present-day Newcastle Central station. The climb was to be at a gradient of 1 in 22 and would have been operated by a stationary steam engine with rope haulage.Bill Fawcett, The Newcastle and Carlisle Railway, North Eastern Railway Association, 2008,

Hitherto railways in the region had had a local focus, but now the Great North of England Railway (GNER) obtained authorising Acts to build from Newcastle to York, forming part of a continuous trunk railway network to connect to London; the project was controlled by George Hudson, the so-called Railway King. At first the GNER was content to get access to the N&CR Newcastle terminus, by connecting with the N&CR at Redheugh and running over its line across the Tyne and up to the Spital. This had the advantage of avoiding a separate, and expensive, crossing of the river, but would have meant a steep descent to Redheugh as the GNER line approached on high ground from the Team Valley, only to climb once again to the Spital. Moreover, William Brandling had made known his intention to reach Newcastle from his line by running at a high level through Gateshead. On 25 April 1837, the N&CR decided to build to their south side, low-level terminus at Redheugh, but to leave the issue of the Tyne crossing open.John Addyman and Bill Fawcett, The High Level Bridge and Newcastle Central Station – 150 years across the Tyne, North Eastern Railway Association, 1999,

Richard Grainger was a developer in Newcastle, and had acquired lands at Elswick (on the north bank of the Tyne west of the proposed Redheugh crossing). In 1836, he published a pamphlet recommending a crossing of the Tyne there, and the formation of spacious railway terminal accommodation there. Drawing attention to the limited scope for extending eastwards from the Spital, and "in the event of an Edinburgh Railway also terminating in this situation, the interchange of passengers, goods, and cattle would be greatly increased".Richard Grainger, Proposal for Concentrating the Termini of the Newcastle and Carlisle, the Great North of England and Proposed Edinburgh Railways, Newcastle, 1836

Grainger's plan was not adopted, and the Brandling Junction Railway reached Gateshead in 1839.K Hoole, A Regional History of the Railways of Great Britain: volume 4: The North east, David and Charles, Dawlish, 1965 The GNER ran out of money and it was superseded in Hudson's railway empire by the Newcastle and Darlington Junction Railway, which opened its line using the Brandling Junction Railway from the south east instead of through the Team Valley. The Brandling Junction line had a terminus in Gateshead at Greenesfield at a high level, and the N&CR line was built climbing on an inclined plane at a gradient of 1 in 23 from Redheugh to reach that. The Newcastle and Darlington Junction Railway opened its line from the south to Pelaw, allowing its trains to reach Gateshead over the Brandling Junction line, in 1844. The tables had been turned, and indeed for a while Greenesfield was the de facto main station for the conurbation of Newcastle and Gateshead.

John and Benjamin Green were a father and son architectural practice active in Newcastle. In 1841 Benjamin Green had proposed a high level bridge for road traffic, substantially on the alignment of the actual High Level Bridge; and sensing the commercial climate he explained how it could be adapted for railway use. He failed to get any financial support, but in 1843 George Hudson was looking for ways to extend his railway network northwards, and the Greens' scheme fitted with his takeover of the Newcastle and Darlington Junction Railway; the line was authorised by the Durham Junction Railway Act 1844 (7 & 8 Vict. c. xxvii) on 23 May 1844, and the act included the road bridge.

Definite plans

The Newcastle and North Shields Railway had opened in 1839 from its own terminus at Carliol Square, on the north-east edge of Newcastle. As a purely local concern, the disconnection was not important, but interest gathered in a railway to central Scotland; the "Edinburgh Railway" foreseen by Grainger. A Scottish concern, the North British Railway, had got its act of Parliament the previous year to build as far south as Berwick-upon-Tweed.John F Addyman (editor), A History of the Newcastle & Berwick Railway, North Eastern Railway Association, 2011,

Now Hudson was intent on capturing the line to Edinburgh for his empire, and he encouraged the development of railway plans to get there; the route such a line might take continued to generate considerable controversy. There was still ambiguity about Hudson's intentions for the bridge—an easier crossing point at Bill Quay, two miles downstream had been considered—and Newcastle Town Council sought undertakings from him. In addition, he promised a footway crossing; this was apparently not a sweetener to the town council, but a commercial decision, expected to bring in £250 a week. The footway crossing was later extended to include horse-drawn vehicles.

Finally, the Newcastle and Berwick Railway was authorised by act of Parliament of 31 July 1845. The line would cross the Greens' high level bridge, starting from the Gateshead Greenesfield station, and commitments made to the building of a bridge by the Newcastle and Darlington Junction Railway were transferred to the Newcastle and Berwick Railway.

Design

The bridge was to be designed by Robert Stephenson; T E Harrison did the detailed design work.

The height of the railway, at about above high water, was determined by the level of the Brandling Junction line in Gateshead. A double-deck configuration was selected because of road levels on the approaches, and to avoid the excess width of foundations which a side-by-side arrangement would require. The deck width was determined by the useful roadway width plus the width of structural members, which gave the railway deck the width for three tracks.

The foundations were to be difficult because of the poor ground conditions in the river, and this ruled out an all-masonry structure, so cast iron or wrought iron was inevitable for the superstructure. A tied arch (or bow-string) design was favoured because the outward thrust imposed by an arch is contained by the tie; no abutments capable of resisting the thrust could be provided here.

Stephenson had used this configuration before; he recorded that, "The earliest railway bridge on the bowstring principle is that over the Regent's Canal, near Chalk Farm, on the London and Birmingham Railway".Robert Stephenson, Iron Bridges, in The Encyclopædia Britannica or Dictionary of Arts, Sciences and General Literature, Eighth Edition, Adam and Charles Black, Edinburgh, 1856

The arch would consist of iron ribs. Fawcett says, "The reasons for not using wrought iron was due to some engineers' distrust of rivetting, the relatively small size of wrought iron plates then available, and the higher cost… On 1 October 1845 when the Newcastle and Berwick Board instructed T E Harrison for their bridges, none of the uses of wrought iron had been developed far enough to be considered as an alternative to cast iron for the High Level Bridge. A tubular bridge might have been considered by Robert Stephenson but the distance between solid and reasonably shallow foundations would have given a span much larger than the Britannia Bridge."Addyman and Fawcett, pages 43 to 45

The depth of rock in the riverbed resulted in a height of from there to the superstructure. Three river piers were permitted by the Tyne Improvement Commissioners, and therefore four river spans of were decided on; there were additional subsidiary spans on the shore.

The cast iron arch ribs are deep at the crown, increasing to at the springing, with flanges; the flanges and webs were three inches thick; in the case of the inner ribs, and two inches for the outer ribs. The rise was , determined by the desired geometry to confine the horizontal thrust within bounds. Each arch was cast in five sections, bolted together.

Stephenson described the tie bars:

The ties consist of flat wrought-iron bars, 7 inches by 1 inch of best scrap iron, with eyes of 3½ inches diameter, bored out of the solid, and pins turned and fitted closely. Each external rib is tied by four of these bars, and each internal rib by eight. The sectional area of each external tie is 28 [square] inches, and of each internal tie 56 [square] inches, giving a total area of 168 square inches. These bars were all tested to 9 tons on the square inch.

The rail deck is supported above the arches by twelve square columns at centres. Suspension rods supported the road deck, and both decks had two layers of diagonally laid three-inch deck timbers on suitable wrought iron cross girders (and rail-bearers in the case of the rail deck).

The main contractors for the ironwork were Hawks, Crawshay, and Sons, who were assisted by John Abbot and Co., of Gateshead Park Works, and Losh Wilson and Bell, of Walker Ironworks, in the production of the castings. The tender was accepted at £112,000. The contract for the bridge piers and land arches and for the Newcastle Viaduct were won by John Rush and Benjamin Lawton of York for £94,000 and £82,500 respectively. The total cost of the contracts at 1999 prices would be over £30million.Addyman and Fawcett, pages 45 to 50

Construction

The first masonry was laid on 12 January 1847. A temporary timber viaduct on the east side was ready on 20 August 1848.

Timber coffer dams were constructed; they were by with two skins, the space between being filled with puddle clay. James Nasmyth had a novel design of steam pile driver; it had first been used in Devonport Docks in 1845; it could deliver 60 to 70 blows a minute; the cycle time with the hand-operated pile drivers formerly in use was four minutes. The drop weight was 1½tons and its stroke was ; one was purchased from Nasmyth.

The ground gave considerable trouble during construction; Stephenson recorded: