|Historical notes: ||The Main Northern line between Sydney and Newcastle was constructed in two distinct stages and in the earliest years, was worked as two separate railway systems. The line between Strathfield in Sydney and the Hawkesbury River was opened on 5 April 1887, with the terminus being on the southern bank of the Hawkesbury River. The line between Newcastle and the northern bank of the Hawkesbury River near present day Wondabyne was opened in January 1888. John Whitton, chief engineer of the NSW railways had campaigned to take the new Sydney to Newcastle railway across the Hawkesbury by bridge when others opposed him claiming a large ferry would be sufficient. Whitton said: "I have never heard of a railway steam ferry across a river where conditions were similar to those of the Hawkesbury River, for instance the steam ferry from Brooklyn to New York is being replaced by a permanent bridge. Those over the Tay, the Forth and the Nile have been abandoned and permanent structures adopted" (quoted in Burke 1995: 95).
The Hawkesbury River crossing was made by steamer until a bridge was completed across the Hawkesbury from Long Island to the north shore of the Hawkesbury River in 1889. A rail platform existed on Long Island before the construction of the bridge was completed. Whilst the main line terminated at Hawkesbury River Station, an arrangement of trackwork, sidings and platforms was provided on the causeway formed by reclaimed land on the eastern side of Long Island where the new Long Island tunnel had been constructed. The station was known as ‘River Wharf’ and the tracks terminated at a wharf at the edge of the waterway. This platform is now known as the former Brooklyn Platform. The platform is still there although now disused and overgrown. It serviced the General Gordon paddle steamer, which left from a large timber wharf called Flat Rock Wharf on Long Island (now removed). The purpose of the arrangement was to allow transhipment between the railways and river ferries, thus allowing passengers to cross the waterway, to another wharf on the northern side of the river, while the bridge was under construction. Two brick-faced platforms were provided at River Wharf. One platform, with a shelter shed, provided for passengers and was located on the eastern, or river-side of the track arrangement. The other was a goods platform, located against the rocky formation of Long Island.
The Hawkesbury River Bridge, the Woy Woy tunnel and the heavy earthworks and tunnels of the Cowan bank were the key engineering works on the Sydney to Newcastle rail link. The construction of the Hawkesbury River Bridge presented unique challenges due to the rugged sandstone terrain and the depth of the river, requiring a bridge that would be the largest in the Southern Hemisphere. The steep sandstone banks of the River meant the bridge would need to be approached from the south by a tunnel, the bedrock bottom of the river was 52m deep in places and the width of the river at the point of crossing was 914m (Lee 1988:107). The design was a significant engineering feat at the time. One caisson would reach 49m below water, the deepest bridge foundation in the world (and taller in height than the Sydney Town Hall) it was also the 4th largest bridge in the world. The construction attracted international media attention (Burke 1995: 98).
The railway Engineer-in-Chief John Whitton who designed and built the railway was not invited to design the bridge due to fall out from a mid 1880s enquiry into railway bridges. The government had also rejected his proposals for a lattice girder bridge, which was estimated to cost 500,000 pounds (Fraser 1995: 45). Instead, an American system of tendering was adopted and companies from around the world were invited to submit designs for the construction of the Bridge (Ellsmore 2000). In April 1886, a tender from the Union Bridge Company of New York, USA, was accepted ahead of 13 other tenders for construction of the bridge. David Burke suggests "it was perhaps the railways’ greatest vote of confidence in the new era of American engineering" (Burke 1995: 93).
Even though the Union Bridge Company was the prime contractor, most of the steel, foundations, cement and stonework were supplied by sub-contractors to the Union Bridge Company, including local contractor Louis Samuel of Sydney who provided stonework for the piers (Fraser 1995: 45) and Arrol and Company who supplied British steel and cement. Arrol and Company had also manufactured much of the steel for the Forth Bridge in Scotland. The Union Bridge Company guaranteed the bridge would be ready in 30 months (by November 1888) and construction commenced immediately.
The bridge was 2905 feet long and comprised seven spans of steel Baltimore pin-jointed trusses, each 415 feet, weighing 1000 tonnes and supported on six stone piers and caissons and with two large stone abutments, one on the south side of the river and one on the north side of the river. The Baltimore trusses were assembled separately on timber falsework on a large pontoon on the north side of Dangar Island and then floated into place at high tide. As the tide ebbed the truss settled onto its bearings (Fraser 1995: 46-47). The work was dangerous due to the local conditions with a number of incidents where spans were nearly lost during bad weather as they were being floated into place. There was also little yard room on either shore of the Hawkesbury or along the rail line and limited landing places for vessels (Burke 1995: 98).
The bridge was typically American in design and was the longest structure to be built in Australia at the time and remained so until construction of the Sydney Harbour Bridge. The American roots of the bridge are reflected in the name given to the construction camp, which was named after the 1883 Brooklyn Suspension Bridge. The town name survives to the present day.
A tunnel (the original Long Island Tunnel), built for duplicate tracks and 483 feet long was driven through Long Island in order to join Hawkesbury River Station to the new bridge over the river. It was of the same brick arch construction as the other tunnels on the Short North including the Woy Woy tunnel. A causeway linked the station to the southern portal of the tunnel. The original Long Island tunnel still exists although it is no longer in use having been bypassed with construction of the new Hawkesbury River Bridge in 1946.
The first Hawkesbury River Bridge was tested on 24 April 1889, with Union Bridge Company engineers, railway engineers, politicians and workers being present. On 1 May 1889, the railway bridge was opened, finally linking the two railway systems. The Union Bridge Company placed large commemorative plaques atop each end of the bridge to mark this significant event, one of which remains on the southern abutment of the bridge in the Long Island maintenance depot. In effect, the railway systems of South Australia, Victoria, New South Wales and Queensland were joined by continuous rail with the opening of the bridge and Henry Parkes used this as a powerful symbol of unification in the lead up to Federation. On 1 May 1889, on the occasion of the opening of the bridge Sir Henry Parkes said: "I feel that the toast entrusted to me represents an event superior to anything that has ever occurred in the history of these great colonies. We are, without any exaggeration of language, assembled here to celebrate an occurrence which has more interest, especially in anticipation of the future, than anything else that has taken place in our history. We have formed a communication by railway which may be said to bind the whole population of Australia in one chain... We have here a representative of the great government of our south, and of the great government of our north, and why should not this occasion be an emblem of our future relations? If the engines meet today with this special greeting, why should we not shake hands and be knit together in bonds that cannot be sundered, and forget the things that created jars that can easily be removed? It is said that the time has arrived for the political federation of these colonies." (Quoted by the Honourable Member for Hornsby, NSW Legislative Assembly, 29 November 2000).
The Hawkesbury River Railway Bridge showed signs of problems within 12 months and the contractors were called back to repair some faults with the piers. Through the 1920s and 1930s, many design faults and problems became evident. By 1925 the original loading of the bridge was considered inadequate and in 1925 it was decided to strengthen the deck. The work took nearly six years between 1926-31 and numerous problems were experienced with the pin-jointed construction of the trusses, which while easy to assemble were difficult to maintain and strengthen (Fraser 1995). In 1937 and 1938, serious cracks developed in a number of piers and divers confirmed major construction faults with the piers below the water line, with the stability of the bridge causing major concerns.
Design and construction of a replacement bridge commenced in 1939, due to concerns that the original bridge would not hold up to extra loading and traffic caused by transport demands of WWII. The old bridge remained in operation until the new one was completed. The design, foundation work and fabrication of the new bridge were undertaken by the New South Wales Government Railways and over 500 men worked on the project, with six dying during construction. A plaque commemorating the lives lost is at the southern end of the bridge, at the northern portal of the 1946 tunnel through Long Island.
The new bridge is located a short distance upstream from the 1889-bridge (piers). It comprises seven steel spans. A new tunnel through Long Island (adjacent to the original 1889 tunnel) and a second tunnel through the sandstone cliffs on the northern side of the river (Mullet Creek tunnel) complete the arrangement.
The trusses for the new bridge were fabricated at Chullora from steel supplied by BHP Newcastle and AI&S Port Kembla (Fraser 1995: 120). It was designed for a heavier loading then it would need to take, possibly learning from the problems encountered with the first bridge. The current bridge is now as old as the one it replaced and has suffered none of the same difficulties. An interesting feature associated with the construction of the new bridge was the assembly site for the trusses, constructed on the north shore of Long Island, just to the west of the alignment of the new bridge. Three wet docks were cut out of the steeply sloping sandstone sides of the island. The docks are still visible as is the small construction platform next to the southern abutment of the 1946 bridge. The docks held floating pontoons, which were construction platforms for the caissons and spans. The pontoons allowed construction at the land based assembly site from where the components were then floated into place. It was a similar concept to the original construction but the assembly site was closer and the number of pontoons provided additional stability to the spans. The three pontoons, in their corresponding wet docks, supported the ends and centre of the spans. Three pontoons were used for the K-trusses of the bridge and two for the Pratt trusses.
Assembling of the trusses began in January 1944 and were completed two years later. On 1 July 1946, the new Hawkesbury River Railway Bridge was officially opened and the original bridge was taken out of service. Apart from the Sydney Harbour Bridge project 1922-32, both Hawkesbury River railway bridges have been the largest, most challenging bridge projects in NSW. The 1946 Hawkesbury River Bridge remains the largest purpose built rail bridge in the NSW system.
In the twentieth century a maintenance depot was constructed on Long Island, specifically associated with the current Hawkesbury River Rail Bridge.
The Long Island tunnel portals are visible from Brooklyn township and the Island and southern bridge abutments are accessible to the public. There is clearly a good degree of interest in the railway heritage of the area within the local community and specialist interest groups. In his Federation Address to the NSW Legislative Assembly the Honourable Member for Hornsby said: "As we continue to celebrate Federation in the Brooklyn area, I want us to think carefully about some of the things Tom Richmond and his colleagues have been putting forward about the possibility of turning Brooklyn into a much more obvious place to study our history. For example, the Long Island embankment across which the rail line goes now is one of the few places that reflects the riches of the recent history of Australia. A recent excursion to the area by the Australian Historical Society brought the comment that members of the society had never seen as much historical interest packed into one location. It is the scene of the Peats ferry railway disaster of 1887. You can still see the remains of River Wharf railway station on Long Island. The Founding Fathers, including Parkes, visited there on a number of occasions, as did the Royal Family in 1901 and 1920. You can still see the construction site for the second Hawkesbury River railway bridge, and the disused Long Island tunnel, the history of which includes one death and a period as a mushroom farm." (NSW Legislative Assembly Hansard 29 November 2000).