Travel Australia

Yimbun Railway Tunnel, Qld

Yimbun Railway Tunnel is a heritage-listed tunnel at Sinnamons Lane, Harlin, Somerset Region, Queensland. The Tunnel was designed and built from 1909 to 1910 by Queensland Railways. It is located between 95.4 km and 95.5 km from Wulkuraka station along the former Brisbane Valley Branch Line formation and is sited beneath a saddle between two knolls. Yimbun Railway Tunnel is a semi-elliptical, concrete-lined, straight tunnel that is 100 metres long and has a gradient of 1:165 against north-bound traffic. It has an earthen floor and is approximately 6 metres high at its apex. Both portals feature the date "1910". The cuttings that form the approaches on the north and south sides of the tunnel extend for approximately 100 metres and approximately 50 metres respectively.

The Yimbun Tunnel, located between Harlin and Yimbun, was designed by Resident Engineer, Hugh Fraser and built by day labourers between February 1909 and May 1910. Relative to their length, tunnels are the most costly of all forms of railway engineering and their problems include hazards such as rock falls. Material must be removed from the bore itself and disposed of. Few types of rock are sufficiently hard to be allowed to remain after excavation without a lining of masonry or concrete. Yimbun Tunnel was constructed as a 110-yard (100 m) concrete-lined straight tunnel with a 1-in-165 gradient rising towards Yarraman. Material from its bore was deposited into Banks Number 14 and 15 on either side of the tunnel's approaches.



The section of line that included the Yimbun Tunnel opened on 22 November 1910 and the extension to Blackbutt was completed during 1911. The next section of the Brisbane Valley Rail Line, to Yarraman, was approved by parliament in December 1910 and opened on 1 May 1913. The last section required to complete the loop to Gympie was approved by parliament on 30 October 1918 but was never built.

The Tunnel is important surviving evidence of the Brisbane Valley Branch Rail Line. Development of Queensland's branch rail network, which began in the 1880s, was vital for the development of the colony through opening land for closer settlement and freighting produce and resources to Queensland's major towns and ports.


Opening of the station to Yarraman, 1913
The Brisbane Valley Rail Line, when commenced in 1882, was the second of Queensland's branch lines. Over the next 30 years it was extended several times to facilitate the transport of timber, livestock and agricultural produce and was intended to become an alternative, shorter route from the South Burnett to Brisbane.

In contrast to other branch lines, revenue from the Brisbane Valley Branch Line was greater than its expenses for the majority of the period from 1902 until the outbreak of World War II when reporting by the Commissioner of Railways on the profitability of individual lines ceased.

The Yimbun Railway Tunnel, constructed in 1910 on the section between Yimbun and Blackbutt, is the only tunnel constructed along the entire Brisbane Valley Branch Line and one of only three remaining intact major rail structures on the Brisbane Valley Rail Line, the others being the Lockyer Creek Railway Bridge at Clarendon and the Harlin Rail Bridge. Of the 55 railway tunnels constructed in Queensland between 1865 and 1931, only nine are recorded as located on branch lines.