A deceptively simple-looking solution may be the engineering answer to one of the most complex parts of sinking the Fremantle Line for the Perth City Link and, at the same time, provide significant energy and carbon savings.
Perth City Link Rail Alliance Design Manager Rail, Bruce McDonald, said the “solid conductor rail” technology - a fixed rail rather than overhead wires - was used extensively overseas, but was new to Western Australia.
“Perth’s rail network is typically powered by overhead wires that must be in a certain arrangement and width
apart,” he said.
“This meant the new Fremantle Line tunnel had to be a certain height to accommodate the overhead wires. And with the above ground redevelopment constraints, the new tunnel would cross above the existing Joondalup Line tunnel with just 70cm between the two.
“Through a number of engineering improvements, including the solid conductor rail, we have reduced the Fremantle tunnel’s height and doubled the gap between the two tunnels to 1.5m.”
Not only does this engineering solution help address a major challenge, it also reduces the distance and gradient the trains will have to travel uphill. Over 40 years, the reduced uphill travel will result in a saving of more than 700,000 kilowatt hours, 630 tonnes of carbon dioxide emissions and potentially more than $150,000 in cost savings. There will also be energy savings in the reduced amount of steel and concrete needed to build.