The Muntapa Tunnel is a concrete railway tunnel located on the route of the former branch line from Oakey to Cooyar in the eastern Darling Downs. The tunnel is one of a small number built on a branch line and it is the only tunnel in Queensland that crosses between the inland and coastal sides of the Great Dividing Range. It was opened in 1913.
Branch lines were secondary railway lines designed to connect rural districts with the main rail routes. They were constructed with the aim of supporting small-scale agriculturalists, dairy farmers and the timber industry. Branch lines were generally of cheaper construction than main lines, more frequent stops were provided and they were often built on road easements to reduce the costs stemming from land resumptions. The first branch line, opened on 12 July 1882, ran from Ipswich to Harrisville. The advent of better roads and faster road transport from the interwar period, eventually led to their demise.
The area between Oakey and Cooyar was populated by small-scale farmers, many of whom were of German origin. The lack of a viable transport route to market hindered the profitability of these small farms. Bullock transport was uneconomic and slow. When arguing the case for a branch line to Cooyar, the Commissioner for Railways, J. Thallon, noted that farms needed to be within 10 to 12 miles (16 to 19km) of a railway line to be viable.
Construction of a branch line to Cooyar had been advocated for some years. As well as improving the viability of farms and stimulating closer settlement along the route, the line would provide Toowoomba and the Darling Downs with access to much needed timber reserves at Blackbutt and Nanango. Of secondary consideration was a proposal to eventually extend the line to connect with Nanango and ultimately Central Queensland.
The line was approved by parliament in 1909 and construction began in September 1910. The principal work on the railway was the over 250m long tunnel at Muntapa. This remains the only tunnel in Queensland that passes beneath the summit of the Great Dividing Range. There are nine tunnels where the main western line from Ipswich climbs the Range en route to Toowoomba, but none of these pass underneath the summit. Tunnelling was a more economic alternative than routing the line around the summit.
The tunnel interior is formed from concrete and it has concrete portals. Concrete was first used in 1880 for the Cherry Gully Tunnel on the Warwick to Stanthorpe line. It was found to be more economical than brick or masonry.
The railway to Cooyar was one of seven branches of the Western Line that was built by day labour. Day labour construction of railways had been introduced by the conservative government in 1901. The practise continued until the mid-1920s. To carry out this work, Queensland Rail maintained a construction branch with engineers and plant and employed construction workers on a temporary basis.
Initially, the revenue raised on the branch exceeded working expenses. Transport of timber peaked in 1915 and from that year coal also began to be railed from the area of Acland. However, from 1916, the branch struggled to remain profitable due to under-utilisation and from 1926, road transport began to seriously affect the profitability of branch lines. This decline was offset, for a time, by cost-cutting measures and the introduction of rail motors. Petrol rationing forced greater use of the rail network by the public during World War II and this improved profitability while rationing remained in place. However, the cost of recovering from neglected maintenance during the War added to the ever-increasing use of motor vehicles accelerated the closure of branch lines after the War.
On 1 May 1964, the line beyond Acland was closed. The Acland to Oakey section was kept open to support the operation of the coalmines at Acland. The mines’ principal customer was Queensland Rail. In the late 1960s, when Queensland Rail completed the conversion of their locomotive fleet to diesel all but one of these mines closed. On 8 December 1969, the Oakey to Acland section was also closed.
The tunnel is now contains the winter roosting site of up to 8 000 Bent-wing Bats: Miniopterus Schreibersii. A picnic table and walking track circuit starting from the picnic area passes through the tunnel.
Article sourced from Qld Heritage Register