Widnes and Runcorn Transporter Bridge

c 1920

One of the saddles which supported and clamped the main suspension cables on top of the towers

2017. Looking from Runcorn to Widnes across the wall separating the Manchester Ship Canal and the River Mersey. The sandstone structure on the Widnes side was the Transporter bridge docking pier, and the small building was originally the waiting room and ticket office, later housing a substation. The red brick building to the right housed the Transporter Bridge Offices. Silver Jubilee Bridge on the left

1900 The Widnes and Runcorn Bridge Co was incorporated

The Runcorn-Widnes Transporter Bridge crossed the River Mersey and Manchester Ship Canal linking the towns of Runcorn and Widnes. It was Britain's first transporter bridge and was by far the longest of its type ever built in the world.

1901 It was designed by John James Webster and John T. Wood. Construction by Arrol's Bridge and Roof Co. began in December 1901 and was completed in 1905.

1912 Consideration was being given to replacing the direct electric motor drive of the transporter carriage by rope haulage. 'This would reduce considerably the weight the car from ninety tons sixty tons. The bridge would be subjected to less strain by the removal of the powor station from the bridge, thereby giving it a much longer life.'

1913 'After being closed since September 16th last for alteration, the Widnes Transporter Bridge, which was the first of its kind to be built in the United Kingdom, and has the longest span (1,000 feet) of any bridge used for road traffic, was re-opened on Friday by Sir John Brunner, Bart. Sir John was really the promoter of the company which directed its erection and subsequently controlled its working for five years. During that period, however, the bridge company found it impossible to make it a financial success and it was on Sir John Brunner's proposal and on his payment of all outstanding liabilities, amounting to £70,000, that the bridge was handed over in August, 1911, as a gift to the Widnes Corporation.
The Corporation, inspired by the success, financial and otherwise, that has attended their two year control of the big undertaking, recently raised a loan of £10,000 for the purpose of making extensive alterations to the transporter carriage and car, and displacing the old electrical system in favour of something more durable and economical, viz., an electrically-driven winch haulage system.
These alterations, together with a few repairs to the structure, have now been successfully completed.
It must be understood, however, that the alterations and repairs have not affected the structure itself. Previously the transporter car and carriage were propelled by means of two electrically-driven motors working through toothed gears onto driving wheels on the rail track. The electrical energy was generated by gas engines in an engine-house situated in the east tower on the Widnes side of the bridge.
All this was done away with, and in accordance with the plans prepared by Mr. Basil Mott, C.E., the engineer to the corporation, this system of propulsion has been altered to an electrically-driven winch haulage system, similar to that in use on almost all the transporter bridges which have been built in this country and on the Continent. This system provides a reduction in the travelling load by some 30 percent.— equivalent to the weight of the car — and tends to more economical working and a reduction of the cost of upkeep, whilst in no way interfering with the carrying capacity of the car.
A new and lighter top transporter carriage has been substituted for the old direct driven carriage, the car has been considerably lightened by the removal of arched girders, and thus a great reduction in the weight of the load has been obtained. Instead of generating the electrical current at the site, a supply has been arranged from the mains of the Mersey Power Company, Ltd., whose works are at Weston Point. .....'

1928 In order to increase reliability, a back-up the power supply was obtained from the United Alkali power station

1961 The bridge continued in use until 1961 when the Silver Jubilee Bridge, Runcorn was opened. The transporter bridge was subsequently demolished.

Transporter Bridges - an Illustrated History by John Hannavy is an excellent source of information, devoting a chapter with numerous illustrations to this bridge.

Design and Construction

Comparing the bridge with the pioneering transporter bridges of Ferdinand Arnodin, we see a number of similarities and differences. The Widnes-Runcorn bridge was a suspension bridge, whereas Arnodin generally favoured part suspension and part cable-stayed. Arnodin used multiple catenary cables, allowing individual replacement, whereas Widnes-Runcorn had just two cables, and these were cradled (the towers were made sufficiently wide to splay the cables, increasing stability). The stiffening girders were of the Whipple truss type, having a series of vertical struts and slender tensioned diagonal ties (X-bracing), following the practice adopted by Arnodin.

Each suspension cable was 1ft. in diameter, and made up of 19 steel ropes bound together, each rope being having 127 wires 0.16" dia., the whole cable thus consisting of 2413 separate wires. The weight of the steel cables was about 243 tons, and the wire had a tensile stress of 95 tons per square inch.

Suspended from the main cables were the two longitudinal stiffening girders (booms), 18ft. deep and 35ft. apart horizontally, the underside of the girders being 82ft. above the level of high water. The girders were firmly braced together horizontally to withstand the wind pressure, which was the heaviest stress to which the bridge would be submitted. The pressure which allowed for in the calculations was the Board of Trade requirement of 56 lb. per square foot. Comparison with other suspension-type transporter bridges shows an unusually high degree of cross-bracing between the girders

To minimise the stress due to deflection from changes of temperature , the girders were hinged at the centre, thus permitting a rise and fall of 2ft. 9in., calculated to occur within a range of temperature of from 0 degF. to 120 degF. To allow for longitudial expansion and contraction, the girders were fixed to vertical rockers, which also carried the overhang of the girders beyond the towers, necessary to support the tranporter car when close into the landing between the towers.

The crossing time was to be about 2 1/4 minutes. The bottom of the gondola was about 12ft. above high-water level, and about 4ft. 6in. clear of the Manchester Ship Canal wall. The trolley was about 77ft. long , and carried by 16 wheels on each rail. Propulsion was by two DC electric motors of about 35 HP each. Unusually, these were mounted in the trolley, driving through the wheels. The electricity was generated in an engine house in the bottom of the Widnes East Tower leg. This contained two Crossley Brothers gas engines of 70 BHP each, one being on standby; two dynamos, a booster and battery of 245 cells made by the Chloride Electrical Storage Co, with all the necessary switchboards, fittings and connections. The generating station was built in three storeys. [As stated above, the propulsion arrangements were completely altered in 1913].

The engineers were John J. Webster of Westminster, and John T. Wood, of Liverpool; the resident engineer being L. H. Chase. The contractors for the steel superstructure were Arrol's Bridge and Roof Co, Germiston Works, Glasgow, who had sublet a portion of the girder, tower and cast iron work to the Widnes Foundry Co. The the masonry work in the approaches and anchorage was done by W. Thornton and Sons of Liverpool. The steel cables were made by the St. Helens Cable Co, and the whole of the electrical installation, including the lighting of the structure, was undertaken by Mather and Platt of Salford Iron Works.

The sinking of the tower cylinders was undertaken by Holme and King. The contractors for the masonry and earth-work of the approaches and of anchorage are Messrs W. Thornton and Son, of Liverpool.

The above information is largely condensed from The Engineer

John Hannavy observes that vibration from the engines was transmitted to the tower in Widnes in which they were housed, and could even be felt at the Runcorn side! . Large single cylinder horizontal engines do need a heavy foundation.

In explaining some of his design choices, John J. Webster anticipated that direct motor drive to the transporter carriage would be less troublesome than than having a haulage cable. He was wrong. Addressing the use of just two large continuous suspension cables rather than numerous smaller cables as used by Arnodin, Webster pointed to the large number of connections and adjustments needed. He recognised the value of being able to replace individual cables in Arnodin's design, he did not regard this as an advantage, believing that his large cables would be more durable in the notoriously corrosive local atmosphere, given their favourable surface area/volume ratio with large cables. Further, he argued that the cables, if properly maintained, would last considerably longer than the rest of the structure! In fact the cables, and presumably most of the structure continued in use for 55 years, until the bridge was replaced by the Silver Jubilee Bridge, Runcorn.

See Also

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Sources of Information

• [2] Wikipedia