Tunnel standards could be changed to accommodate new intercity trains on Blue Mountains Line

Transport officials want to relax standards for the minimum distance allowed between trains and rail tunnel walls so that the new intercity fleet can travel all the way on the Blue Mountains Line between Springwood and Lithgow.

The intercity trains being built in South Korea will be about 3.1 metres across, which will be too wide for them to travel beyond Springwood to Katoomba and Lithgow without an upgrade of the rail line.  

While planning is under way to alter stations and shift slightly or replace sections of rail track, eight of the 10 tunnels built early last century between Newnes Junction and Zig Zag station in the Blue Mountains need to be upgraded so that the new trains can pass through them side by side.

Transport for NSW's preferred option is to scrape away at the tunnel walls to widen them and alter the minimum clearance standard to allow the new intercity trains to run on both lines and pass each other through the tunnels.

Concept designs for the new intercity train fleet. Photo: supplied.

Concept designs for the new intercity train fleet. Photo: supplied.

Under the current standards, the minimum distance allowed between the outline of a train in motion – known as the kinematic envelope – and tunnel walls is 200 millimetres.

Asked what the minimum distance would now be, Transport for NSW said in a statement that the “new draft standard to ensure the safe operation of trains is being finalised and reviewed by the train designer and the Assets Standard Authority”.

At present, the state's clearance standards mean V-Set trains dating to the 1970s and narrow diesel-powered locomotives such as the XPTs are the only types in the government-owned fleet that can pass through the “Ten Tunnels Deviation” in the Blue Mountains.

Labor leader Luke Foley said people had a right to be suspicious that the safety standard was to be changed to fix the government's “bungle” of buying trains that did not fit through the tunnels.

“[Transport Minister] Andrew Constance should tell us what it is going to cost to widen the tunnels and complete the track modifications from Springwood to Lithgow,” he said.

“He also needs to detail what special operational restrictions will be imposed including speed limits and how these will be enforced.”

But Mr Constance said Labor had spent 16 years in government without bothering to undertake a long overdue upgrade of the Blue Mountains Line.

“I can’t understand why Luke Foley and the Labor Party don’t want a modern track and train upgrade for the people of the Blue Mountains,” he said. “Parts of the network are over 150 years old and they need to be upgraded – it just makes sense.”

Transport for NSW always knew that the upgrade to the tunnels would be necessary to deliver new trains for intercity passengers on “physically constrained parts of the rail network”, he said.

A report on the tunnel upgrade said transport officials did consider shifting the track and cutting further away at the tunnel walls so that the new trains could travel on both lines and pass each other.

However, this option was “discounted due to the high cost” and the need to close tunnels for several months, which would cause significant disruption to services on the rail line.

The government has not revealed what the upgrade to the Blue Mountains Line will cost, arguing it is still subject to a tender process and needs to remain commercial in confidence.

The $2.3 billion contract to build the 512 double-deck train carriages and locomotives does not include the upgrade to the Blue Mountains Line or a new maintenance facility at Kangy Angy on the Central Coast.

The NSW Auditor-General warned several years ago that the total cost of the project would rise to as much as $3.9 billion.

Most of the work on the tunnels in the Blue Mountains will occur during scheduled track possession periods over two years.

However, some of it will require extended shutdowns of up to 15 days at a time, during which trains will not run and replacement buses will be put on to ferry passengers.

Subject to approval, construction is expected to begin late this year and take about two years.

- This article first appeared on the Sydney Morning Herald.