[1] On 7 April 1887, the single track section of the Main North line was opened between Hornsby and the Hawkesbury River.
Passengers and goods heading north now unloaded at the River Wharf platform on the eastern end of Long Island, transferring to the double decker, rear paddled-wheeled steamer General Gordon for a three-hour trip out to Broken Bay and up Brisbane Water to Gosford where the train service recommenced.
Firstly, optical measurements were taken of the deformation under load at the centre of each span, taken by two sets of observers positioned atop the stone piers.
Load testing was carried out on 24 April 1889 in the presence of various dignitaries including Henry Deane, the Assistant Engineer in Chief of the New South Wales Government Railways.
This led to the undesirable practice of the bridge being used as a crossing point for trains, thus regularly subjecting the structure to maximum stress loads.
The work took nearly six years between 1926 and 1931 and numerous problems were experienced with the pin-jointed construction of the trusses, which while easy to assemble were difficult to maintain and strengthen.
The depth of sediment had made it impossible to reach bedrock with the foundations on the southernmost pier and it seems that this was the cause of the structural faults.
The amount of traffic being carried (up to 100 trains a day) during World War II made the replacement extremely urgent and prior to the new bridge being brought into operation the speed limit on the old bridge was restricted to 23 km/h (14 mph) and finally down to 6 km/h (4 mph) with tracks altered to gauntlet configuration to ensure trains could not pass.
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.
[1] The southern abutment is constructed in concrete and face Hawkesbury sandstone and rises approximately 20 metres (66 ft) above the shoreline.
Within this 1960s structure and affixed to the top of the abutment is a large cast iron plaque which was formerly located on the crest of the first span of the original rail bridge.
[1] Immediately to the north of the southernmost abutment, but slightly off alignment, is a concrete footing on the shoreline at the mean high water mark, which may have been linked to construction of the former or current bridges.
The abutments and piers of the bridge as well as the 1886 Long Island tunnel are tangible reminders of these significant events and the symbolic power they had for people at the time not only in NSW but throughout Australia.
Both the 1889 and 1946 bridges and associated infrastructure on Long Island also demonstrate the significant investment in the railway system of NSW in the late nineteenth and early twentieth centuries.
The contrast of the man-made bridges and tunnels with the rugged and beautiful natural landscape of Hawkesbury River allows passengers and visitors to appreciate the engineering achievements of the railway line's construction.
There is enough extant fabric in the remaining abutments, piers and the Long Island tunnel to demonstrate the engineering achievements of the original Hawkesbury River crossing.
[1] The 1946 railway bridge was also a major technical achievement at the time of its construction, its large riveted steel trusses and its footings were still among the deepest in the world.
[1] Hawkesbury River Railway Bridge was listed on the New South Wales State Heritage Register on 2 April 1999.
[10] This Wikipedia article contains material from Hawkesbury River Rail Bridge and Long Island Group, entry number 01040 in the New South Wales State Heritage Register published by the State of New South Wales (Department of Planning and Environment) 2018 under CC-BY 4.0 licence, accessed on 2 June 2018.