The Scenic Rail Upgrade

Client: Grindley Constructions
Design: Scaling,Rock Bolts, Shotcrete and Simulated Rock Finish
Area: 2000m2
Completion: 25/04/14

The Scenic Railway located at Scenic World in the Blue Mountains descends 310m through a cliff-side tunnel, emerging into ancient rainforest at the Jamison Valley floor. It has been operating since 1945, and has thrilled 25 million passengers on nearly 700,000 journeys.

The Scenic Railway was originally constructed for a coal and oil shale mining operation in the Jamison Valley in the 1880s, in order to haul the coal and shale from the valley floor up to the escarpment above. From 1928 to 1945 it carried coal during the week and Passengers at weekends. The coal mine was closed in 1945 after which it remained as a tourist attraction

It is the steepest cable-driven funicular railway in the world, with the steepest incline of 52 degrees over a total incline distance of 310m. The current train carriages were installed in 1994 and have made over 400,000 journeys. The new Swiss-designed railway carriages will comprise the fifth vehicle to operate on the former coal mine track since 1945.

The Scenic Railway is currently investing $30 million in a redevelopment Including new larger train carriages with new train tracks, bigger buildings, a new winch and all new control systems.  This has required additional excavation of the existing tunnel to accommodate the larger carriages. Other works included in the upgrade are new top and bottom platforms and an historical interpretation.

The upgrade works will retain the character and history of the railway, but will allow the necessary safety upgrades. Scenic World engaged Grindley Constructions to carry out the building and construction works, and Sinclair Knight Merz, as the geotechnical consultants.  The RIX group were engaged in October 2012 to carry out the tunnelling works.

Rix specialist personnel were used to install rockfall mesh and protection measures, and scale approximately 2000m2 of the rockface. Access was provided utilizing rope access from above the chasm which exists at the southern end of the tunnel.

Enlargement at the portal was carried out by hand excavation in 2.5m increments, including drilling and installing 3m long rock anchors, mesh and shotcrete. Rix were also required to remove the existing concrete support slab in the tunnel while keeping the rock mass stable with rock anchors punched through from the area above.

To accommodate the new trains the tunnel needed to be enlarged. This involved hand excavation and installation of 100mm of mesh reinforced dry shotcrete, with 1.8m, 2.1m, and 3.0m long rockbolts depending on the location and access, as the floor to roof dimension sometimes did not allow for the installation of the longer bolts.  About 140 ton of dry shotcrete was used.

An 8m long, by 2m deep, by 2m wide service tunnel was also excavated by hand under the top platform to allow access for the maintenance fitters to the underside of the train.

Rock pins were drilled and installed along the entire length of the incline to secure the new rail footings and drainage material was also installed at 300mm centres to handle the excessive inpours of water that occur during heavy rains.

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