The Woy Woy railway tunnel is a heritage-listed railway tunnel located between Wondabyne and Woy Woy stations on the Main Northern railway line in New South Wales, Australia. The dual-track tunnel was opened on 16 January 1888. It was added to the New South Wales State Heritage Register on 28 June 2013. Description Woy Woy Tunnel is a double track railway tunnel passing beneath a sandstone ridge between Brisbane Water and Mullet Creek. The tunnel is of brick construction throughout. The tunnel was originally built for double track service and thus did not require widening when the line was duplicated in 1906. The brick portals feature a brick string course, but are otherwise plain. The tunnel is horseshoe shaped, straight and has an average 1 in 150 gradient. There is a long cutting in bedrock leading to both portals. At the time of its completion in 1888, the tunnel was the longest railway tunnel in Australia. Construction history Construction commenced on 1 March 1884. There was a breaking through ceremony on 17 July 1886; and the official opening was held on 16 January 1888. During construction the tunnel entrance had a crimson streamer stretched across it with the Latin phrase Labor omnia vincit, meaning, Hard work conquers all. A hill rises above the tunnel. Construction took place without cessation, night and day, excepting only upon Sundays; and approximately 300 men were employed in the excavation works; and over of gunpowder and of dynamite. Perforation work for the tunnel was provided by ten percussion rock-drills using compressed air obtained from a engine. Approximately of rock were excavated and approximately 10,000,000 bricks were laid, supplied by Gore Hill Brickworks. No less than 10,000 cement casks were used. Flooding of the area occurred in 1887, resulting in an inspection of the site by Henry Deane, The Herald reported: Homebush-Waratah line The construction of the Homebush-Waratah line was broken up into sections: Hornsby-Hawkesbury, opened 7 April 1887; Hawkesbury River Railway Bridge-Mullet Creek, , opened 1 May 1889; Mullet Creek-Gosford, , opened 16 January 1888; Gosford-Waratah, , opened 15 August 1887. Between April 1887 and May 1889, the Woy Woy Tunnel's major benefit of significantly reduced travel times were not able to be fully appreciated by passengers until the completion of the Hawkesbury-Mullet Creek section of track which involved the construction of the first Hawkesbury River railway bridge. Prior to the opening of the Hawkesbury-Mullet