The New England Corridor - connectivity?

If the a standard gauge New England Corridor was ever to be revived, it may only be necessary to dual or standard gauge as far north as Warwick. The simple fact is the existing Toowoomba Range crossing could not be standard gauged in its current form, so if rail-to-truck transit was the only alternative between the New England corridor and Brisbane, then Warwick offers lower reinstatement costs and faster transit times than a train continuing to a road interchange at Toowoomba. But can the 1867 Toowoomba Range corridor be made standard gauge friendly? Presently the only solutions on the table are multi-billion dollar government-funded commuter-rail base-tunnels under the Toowoomba and Litte Liverpool Ranges - originally proposed for completion in 2026 but now well and truly fallen off the table simply because of their extreme cost. In fact cost is always the issue with the Toowoomba Range Corridor - finding the best way to upgrade this line will always be beyond the value of the upgrade, meaning high-cost corridor replacement has not been undertaken. However, the net result of waiting for the big money option to be funded has meant lower cost alternatives have never been properly investigated.

So if the best option is un-fundable for a freight solution, what else can be done? The current 1867 alignment has a ruling gradient of 2-percent, with curve radii as small as 100m and crossing loops of around 700m. Added to this, several heritage listed tunnels prevent day-lighting the most restrictive structures on the corridor, which additionally restrict container and rollingstock heights. Even so, increasing minimum curve radii to 200m within the existing corridor while removing some curves at the penalty of a slightly steeper grade could be undertaken, including bypasses of the heritage tunnels with parallel cuttings. The shallow ridge the highly restrictive 'Victoria Tunnel' passes under at Yarongmulu could be open to such treatment as well. Cost? Similar work undertaken in 1998 on the similarly curved Drummond Range in Central Queensland was less than $30-million. In March 2011, following unprecedented flooding which caused 260 washouts and landslides, the Toowoomba Range Corridor was reopened after three-months work for another $30-million (about $1-million/kilometre). Meanwhile a much more substantial highway realignment of the Cardwell Range in North Queensland is costing $28.75-million/kilometre. Based on this, a staged curve realignment project of this corridor should be somewhere between $10-million to $15-million/kilometre for the two range crossings indicating a total cost of around $500-million. Still a lot of money, but it will provide a potentially dual-gauged double-stack corridor with minimum speeds twice that of present...which might even be sufficient for commuter rail options as well (Helidon-Toowoomba passenger times would be less than 50-minutes). Not the best solution, but almost certainly the only one which has a chance of being funded.

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