Warrington Transporter Bridge
The present Warrington Transporter Bridge (or Bank Quay Transporter Bridge) across the River Mersey is one of three surviving bridges of this type in the UK. It no longer operates.
There have been two transporter bridges here. The surviving bridge was built in 1915, supplementing a smaller capacity suspension-type transporter bridge opened in 1908.
The bridges connected two parts of the factory site of Joseph Crosfield and Sons, which was bisected by the River Mersey. There was a sharp bend in the river here, and it changed direction, from heading NNE to SSW, leaving a 'peninsula' which acquired the name 'Tongue Island'. Crosfield's soap works, long familiar to passengers on the West Coast main line passing through Warrington Bank Quay Station, occupied a large area on the outside of the bend. The 1905 map shows that the 'tongue' was unoccupied save for a solitary small building. Crosfield's wanted to expand onto that land, hence the need for a bridge. The tidal river was still used by masted vessels, so the bridge needed to be high.
ORIGINAL BRIDGE
James Newall (1860-1950) of Joseph Crosfield and Sons was charged with providing a bridge to cross the Mersey to link the company's existing site with the area for expansion on the other side of the river. After examining four options, a transporter bridge was chosen. The requirement was to convey a load of 2.5 tons across the 250ft. span at 6 mph.
Thomas Piggott and Co won the initial design competition, and were awarded the construction contract. In referring to the difficulties in designing the stiffening girder,The Engineer stated that 'Perhaps the most helpful suggestions of a way out of the difficulty have been those made by Professor Alexander, and also by Messrs. Merriman and Jacoby, and it was decided to proceed on lines somewhat similar to those recommended by these authorities.' It is not clear whether they were directly involved, or whether the guidance came from their published works.
James Newall, on behalf of Crosfield's, laid down the two anchorages and the foundations for the towers before the stucture was erected.
The design principles were described in interesting articles in The Engineer in 1908[1][2].
The bridge survived until at least 1962. A pipe bridge now occupies the site.
SURVIVING BRIDGE
The present bridge has a span of 200 feet. It is 30 feet wide, and is 76 feet above high water level, with an overall length of 339 feet. It was designed by William Henry Hunter, and built by William Arrol and Co. It was privately owned and, like the original bridge, it was built to connect the two parts of Crosfield's site. It was originally used to carry rail vehicles up to 18 tons in weight, and adapted to include road vehicles in 1940. In 1953 it was modified to carry loads up to 30 tons.
It was last painted in 1956. By 1976, recognizing the historical significance, Crosfield's were keen to hand the bridge over to an organisation who would look after it.[3]
Although it has been out of regular use since c.1962, it is still extant. However, although it is a listed structure, it is at risk of 'demolition by neglect'. A group has been established in the hope of preserving the bridge, called 'Save Warrington Transporter Bridge'[4]. There is also the official 'Friends of Warrington Transporter Bridge' website here, which includes detailed directions for access to view the bridge.
AN ACCOUNT OF THE BRIDGES FROM 1956[5]
' ..... The story goes back to 1905, when a cement plant was established on the Cheshire bank, and there was the continual problem of conveying the finished product to the Lancashire side. To simplify the problem, the firm commissioned the firm of Messrs. Thomas Piggott & Co., of Birmingham to build what was then a somewhat revolutionary type of bridge across the river.
ORIGINAL USE
It was in effect a suspension bridge with a trolley driven by a continuous cable. There was no car, but a sling was used to whisk cement from one side of the river to the other. That bridge is no longer used for its original purpose, but is still there to carry pipelines and electric cables across the river.
The experience of transporter bridges was evidently sufficient to inspire the management as early as 1910 to consider another bridge to convey personnel and railway wagons to the site available for development on the south bank.
The design was entrusted to a Manchester architect, Mr. W. Henry Hunter, and the bridge was built by Sir William Arroll, of Glasgow, who was also responsible for the steelwork on the Widnes bridge.
The work was superintended by Messrs. Crosfield's own engineers. By 1915 the bridge was complete. Unlike the Widnes Transporter, which is a Suspension bridge, the Crosfields bridge was a simple box girder cantilevered at both ends. [Note: It has truss girders, not box girders]
The span between the towers is 227 feet — compared with the 1,000 feet of the Widnes bridge and the overall length, including the cantilevers, is 339 feet. The clearance between the underside of the bridge and high water level is 75 feet. The cantilevers project for 56 feet at either side. The bridge portion, which is 20 feet wide, is supported by four towers, two at each side of the river, forming an arch over the docks. Both docks are brickfaced and are very simple in lay-out, with only a rail at each side for protection. Two rails run along the length of the boom and form a track for the trolley which runs on 32 wheels, 16 at each side, which are spaced equidistant.
The car, which is suspended on steel cables, is 20 feet wide and 30 feet long, and 20 feet above the deck is a steel mesh to protect the occupants from anything which might fall from above.
Its capacity is 35 tons — though in practice this can rarely be achieved because of its size. Normally a loaded railway wagon or an eight-wheeled tanker is the biggest load it has to carry. Only one vehicle at a time can be carried. The trolley is driven backwards and forwards on a continuous haulage rope via a friction drum. There is a 40h.p. electric motor at the extreme end of both cantilevers, but only one motor is in use at a time. The second motor is for emergency or breakdown use.
AN EXTENSION
The trolley wheels are self-lubricating, and give little trouble on that score, but have steel tyres which need to be frequently changed. The wheels are mounted on to the trolley by means of stub axles. For many years, only railway wagons were carried across the river, for the simple reason that permission could not be obtained to construct a road for vehicles. During the war this was changed, and in 1953 arrangements were made for the car to be extended to accommodate larger tankers.
Because of the very considerable importance of the transporter link, the work had to be carried out during the annual holidays. Messrs. Crosfields have long adopted the practice of shutting down the Lancashire and Cheshire works at different times, and the time of the Cheshire works shut-down was chosen. The engineers. Messrs. Arrols, had from Friday until a week the following Monday to carry out the alteration. As it happened, the parts had already been prefabricated, but placing them in position in the given time was a bit of a rush.
Though a private bridge, it is extremely busy. In fact, in an average day it conveys about 100 road vehicles and 20 railway wagons from one side to the other, and only one vehicle at a time is possible, it appears to be working continuously.
Unlike the Widnes bridge, the Crosfields Transporter is in very good condition, and the engineers consider that it has an indefinite future life. It is not the only way across the river, however. Personnel are normally carried by steam ferry. There are twin sets of landing stages, and the ferry is kept at it all the working day. Incidentally, the Cheshire side of the river is known as "Tongue Island" because of its shape. It is not really an island, but there no approach to it by road.'
Note: See here for a description of Crosfield's cement production on the 'Tongue Island' site between 1907 and c.1929, using soap works waste (calcium carbonate from conversion of sodium carbonate to sodium hydroxide) and Mersey alluvium.[6]
STRUCTURE OF THE PRESENT BRIDGE
This is a cantilever bridge with truss girders. The towers, bolted to the brick-faced concrete plinths, are cantilevered inwards and outwards (i.e. towards and away from the river). Effectively, the towers are T-shaped, but with curved members acting as brackets to support the horizontal part of the 'T'. Boxes (Fig 5) built into the outboard ends presumably contain pig iron to counterbalance the weight of the centre span, which is supported by, and connected to the cantilevered portions which project over the river. It appears that 'palms' on the top chords provided the initial support, and that pins in the top and bottom chords provide the main connection. The pins are just visible on the extreme left hand upright member in Fig. 3. Fig. 3 also shows many of the features described in the next two parageaphs.
The top chords of the girders each comprise a pair of modestly-sized channels, arranged thus: ] [. The bottom chords are similar, except that the arched portions are stiffened by having plates riveted to the webs.
The vertical members of the girders, between the top and bottom chords, also have channel-section members, arranged [ ], also joined by x-bracing. Transeverse beams, comprising pairs of channel-section members, are attached to each of these uprights. and these support simple I-beams which run most of the length of the bridge. Attached to the bottom flanges of these beams are railway beams, on which the trolley runs. The idler pulleys for the hauling cable are supported by pulleys attached at mid-span of several of these cross-beams.
The diagonal truss members are made from pairs of flat bars or angle-section. These are either cross-braced or unconnected, depending on whether they act in compression or tension.
The main part of each tower has two pairs of stiff legs to which the main structure of the girders, including the curved members, is attached. Fig.6 shows the lower end of one of these legs, and one of the holding down bolts is just visible (these bolts can also be seen in Fig. 7). the These legs are provided with additional bracing against transverse deflection. The structure which provides this additional bracing is of relatively lightweight construction, as can be seen on the LHS of the tower in Fig 4. It will be seen that the RHS is provided with more structural steelwork. This is partly or wholly because the staircase is there, providing access to top of the bridge and to the motor room.
SOME DETAILS
In Fig 10 we see, on the left, the two I-beams which support the rails for the trolley, and slung beneath each of these is a block, presumably a wooden buffer. To the right is wire rope going up at an angle to a pulley and descending to a stack of circular weights - presumably to tension the large return pulley by pulling its axle to the right.
In Fig 11, note the vertical cylinder on top of the beam. This was evidently a shelter for the plucky wartime firewatcher! It was probably a repurposed air receiver.
Fig 7 shows the 'gondola'. In ascending the ladder to get into his gazebo, the operator probably wondered why it needed to be so high.
See here for excellent drone photographs.
See Also
Sources of Information
- [5] Wikipedia