On February 8, the first of four tunnel boring machines (TBMs) which are around 100 meters long arrived in Melbourne from Germany.

These will operate like moving factories as they travel deep beneath the city’s surface. Giant cutting heads will burrow through soil and rock as the machines plough through the path of two twin nine-kilometre tunnels to be constructed as part of the $11 billion Melbourne Metro project.

Each TBM will head away from the city before being retrieved in Kensington and South Yarra. They will then be dismantled and trucked back to the start to be relaunched towards the city.

All up, the project will generate 7,000 jobs and will enable half a million extra passengers to use the city’s rail network each week by freeing up space in the current underground loop.

As well as the Metro project, extra work in Melbourne is being created through an eight-year program to remove 50 dangerous level crossings.

Victoria is not alone in undergoing massive rail construction developments. In New South Wales, the North West Rail Link is now mostly complete but the state still has much work going on through the Sydney Metro project – not to mention Parramatta Light Rail. Queensland has the 10.2 kilometre Cross River Rail Project from Dutton Park to Bowen Hills whilst Perth has the long-term Metronet project involving up to 72 kilometres of new passenger rail and up to 18 new stations.

Courtesy of these, Australia has a rail building boom. In the most recent edition of its Construction Market Forecasts released in November, Australian Construction Industry Forum (ACIF) says it expects the dollar value of work done on building of railways, bridges and harbours to almost double from $8.873 billion in 2017/18 to $14.437 billion in 2020/21. Already, activity has risen from a low of $5.9 billion as recently as 2015/16.

Benefits will be widespread. Having nearly doubled from $1.746 billion in 2013/14 to a forecast $3.202 billion in 2018/19, the value of work in New South Wales is expected to hit $4.7 billion by 2020/21. In Queensland, activity will surge from $1.0 billion in 2017/18 to $2.665 billion by 2022/23. Leading the way, however, will be Victoria. In that state, the value of work will more than triple from $1.449 billion in 2016/17 to $4.664 billion by 2020/21.That represents an almost fivefold increase compared with recent lows of $949 million in 2014/15.

ACIF lead forecaster Kerry Barwise says the boom is being driven by government policy.

When commencing a push to address infrastructure deficits several years ago, governments first opted for road projects – many of which were close to being ‘shovel ready’. Even then, however, Barwise says several states flagged interest in rail. In places such as Melbourne, these projects have come online later compared with roads due to the amount of planning involved. Some are now coming through. As well, the push for rail is being driven by urban consolidation and the need for transport to cater for this. In NSW, second and third stage developments are coming through now that projects such as the North West Rail Link are almost done.

“Many of these projects were foreshadowed as a high priority by Infrastructure Australia,” Barwise said.

“It has taken time for them to come through to the point where they have been funded and are now coming through as actual construction projects.”

Whilst the growth in activity is welcome, Barwise cautions that having so many developments going simultaneously will place pressure on resources and costs. This was especially in skilled areas such as tunnelling.

“Victoria and NSW are rolling out these projects at the same time,” Barwise said.

“There is a limited pool of labour resources. The danger is that they will be ramping up together and acting in competition, and that there will be unexpected delays and cost overruns.”