|
Bremer River Rail Bridge is a heritage-listed railway bridge at off Bremer Street, North Ipswich, City of Ipswich, Queensland, Australia. It was built from 1865 to 1915. It was added to the Queensland Heritage Register on 11 December 2006. == History == The Bremer River Railway Bridge (1915) and the adjacent cast-iron piers (1897) and masonry bridge abutments (1897 and 1865) are located on the banks of the Bremer River near the business centre of Ipswich. The 1865 abutments are the remains of the most substantial bridge on the Main line railway, the first railway to be constructed in Queensland.〔 Queensland's colonial government fostered the development of railways as a means of developing Queensland and providing social benefits. It was argued that rail would reduce freight costs and save travel time for passengers. An added incentive for rail development in Queensland was the very poor state of the roads. In wet weather especially, this hampered the transport of freight. Priority was initially given to providing a railway link to coastal ports for the well-established and influential pastoralists of the Darling Downs.〔 Ipswich was chosen as the eastern terminus of the railway because of its importance to the Darling Downs pastoralists. The township was a river port, the head of navigation, located at the intersection of routes to the Darling Downs and Upper Brisbane Valley. It was a major inland port servicing the Darling Downs and Ipswich residents together with many pastoralists cherished the hope that the town might become Queensland's capital. Brisbane eventually assumed that role but Ipswich remained an important regional centre.〔 North Ipswich was originally chosen as the site for the terminus. However, the residents of Ipswich had wanted a high-level bridge to connect north and south Ipswich since the early 1860s. So it was decided to extend the railway to south Ipswich by building a road-rail bridge across the Bremer River. This extension added to the overall cost of the line without contributing to the efficiency of the route. Extra expenditure was needed for the bridge and the additional three kilometres of line needed to reach the new site.〔 Abraham Fitzgibbon, later engaged as Queensland's first Commissioner for Railways, was appointed Chief Engineer on contract and Sir Charles Fox and Son, an engineering firm based in England, were appointed as consulting engineers. Peto, Brassey and Betts, contractors with worldwide railway construction experience, were engaged to construct the line, including the Bremer River Bridge. Several months prior to the completion of the line, operating staff also began to be recruited.〔 The original North Ipswich Railway Workshops were completed in 1864 on a cramped site adjacent to the Bremer River close to the northern end of the planned bridge. It soon began to produce rolling stock for the new railway completing an engine truck in 1865 and ten wagons in the following year.〔 The first Bremer River bridge was designed by Sir Charles Fox and Son and pre-fabricated in Britain. This may explain the pin-jointed members, as these would have simplified the task of assembly in an economy with little skilled labour and unsophisticated manufacturing technology.〔 It was a deck-type iron bridge with pin-jointed lattice girders on cast-iron cylinder piers. It had substantial abutments (extant) made from sandstone, similar to that used in the abutments of the Heiner Road Bridge over the former Wharf Branch Line. The stone is believed to have been quarried locally at Denmark Hill. Comprising three spans of 150 ft (45.7m), it was 67 ft (20.4m) above the high tide level. 12 ft (3.7m) of the width of the bridge was reserved for rail and 23 ft (7m) for general traffic. It was an uncommon example of a road-rail bridge and this explains its wide abutments.〔 The Bremer River Rail Bridge was not the first iron bridge to be completed on the line. The first was completed in April 1865 and crossed Wide Gully. However, the Bremer Bridge was described in the Brisbane Courier (1 August 1865) as ''"the most important structure on the first section of the line"''.〔 By Saturday, 29 July 1865, the bridge was sufficiently complete to allow a locomotive to cross safely carrying Arthur Macalister (the Lands and Works Minister) and Abram Fitzgibon. On 31 July, Governor George Bowen officially opened the railway at Bigge's Camp (now Grandchester), the western terminus of the line. Abram Fitzgibbon, Albert John Hockings (the Mayor of Brisbane) and Robert Herbert (the Colonial Secretary), also participated in the ceremony attended by a large contingent of pastoralists.〔 By 1866, it became evident that the northern abutment of the bridge was inadequately designed. A report in March 1867 cited inadequate foundations, poor quality masonry and lack of drainage as the cause of the problems. It had to be rebuilt following a flood in May 1867, when cracks appeared under each girder and nearly every stone in the face showed signs of fracture or damage.〔 In 1875, with the opening of the Ipswich Deviation, the main western line bypassed the Bremer Bridge. Nevertheless, the bridge continued to carry increasingly heavy loads. This is because it provided access to local coalmines and, more significantly, the North Ipswich Railway Workshops, Queensland's largest facility for manufacturing and maintaining steam locomotives and rolling stock. Expansion of the site took place in 1877 and in 1884 construction of new and larger workshops commenced at an adjacent site.〔 Given the ongoing expansion of the Workshops and Queensland Government Railways' program of continually upgrading its locomotives to more powerful ones, the bridge was required to bear a growing volume of traffic including increasingly weighty locomotives en route to or from the Workshops.〔 In 1881 the new Ipswich signal cabin and state of the art interlocking mechanism was installed at the southern end of the bridge at the junction of the main western line and the line across the bridge to the Workshops. The cabin of the signal box was unusual in being three, rather than two storeys high, so that the signalman could see over the top of the bridge and also the main line to the west. It was the only such mechanism to be installed in Queensland outside Brisbane at the time and this is indicative of the high volume of traffic passing through the junction.〔 In October 1893, it was found that the cross girders of the old bridge were overstrained and in many cases showed fracture of the material. A March 1894 memo to the Chief Engineer's Office stated that the bridge was no longer strong enough to carry the current traffic. Instead of recommending the bridge be reinforced, it proposed that a new bridge should be built. This was partly prompted by on-going problems that had been experienced with the Ipswich Town Council over maintenance of the shared bridge. It was decided to transfer the old bridge to council ownership for the exclusive use of road traffic. The contract for the new bridge was let in January 1896.〔 This bridge was constructed by Beatty and Walsh under the supervision of Government Engineer, F. L. Keir. The resident engineer was C. S. Graham. Messrs J. W. Sutton and Co of Brisbane cast the cylinder piers and made the girders. The 1897 Bremer River Bridge and the Indooroopilly Bridge were the first to be riveted using a pneumatic machine.〔 The bridge was a three-span, six-panel, through Pratt truss design resting on concrete filled cylinder piers. It is believed to have been the first bridge to use a Pratt truss on Queensland railways. Like the earlier bridge, it had masonry abutments; these, together with the piers, are still extant. The new bridge only carried a single set of rails. Its substructure was painted maroon and its superstructure French grey.〔 First introduced in , Pratt truss bridges became Queensland Government Railway's preferred form for major spans until the adoption of reinforced concrete. Patented by Americans Caleb and Thomas Pratt in 1844, the Pratt truss was a very popular design in the United States. The design was such that lighter materials could be used in construction. The diagonal members could be thinner since they were subject to tension forces only and the trusses were deeper enabling the use of bracing across the top members. This stabilised the trusses thus allowing lighter members to be used. This resulted in a more cost-efficient design.〔 A major expansion of the Ipswich Workshops at the beginning of the 1900s, together with further upgrades of locomotives led to constantly increasing demands on the bridge. The first 12-ton axle load engines, the B17 locomotives, were built at the Workshops between 1911 and 1914. In 1913, the Workshops commenced building C18 locomotives. Together with their C19 derivative, these were the largest conventional locomotives ever to run on the Queensland Government's railways.〔 Between 1913 and 1915, the substructure of the 1897 bridge was widened and a third bridge (still extant) was built with stronger spans. Like the 1897 bridge, it was a through Pratt truss design. The new bridge was strong enough to carry all of the locomotives in use at the time but the 1897 bridge was restricted to C16/C17 locomotives and was used for shunting operations only.〔 In March 1967, the 1865 bridge was demolished. It had been rendered redundant in 1965 by the construction of the David Trumpy road bridge. The 1897 bridge was removed in 1987 leaving just the extant span on double track piers.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bremer River Rail Bridge」の詳細全文を読む スポンサード リンク
|