I basically support C Williams' call for a national high-speed rail network (Letters, June 1), despite a report from the Grattan Institute which concludes that such a network would not be cost effective. 

A national fast-rail network would not pass a cost-benefit test mainly because of the long distances and low average population density involved if Adelaide - let alone Perth - were part of the network. A south-eastern network, taking in Melbourne, Canberra, Sydney and Brisbane is far more likely to be financially viable.

As C Williams implied, the Grattan Institute's claim that a fast-rail network would take "nearly 50 years" to build is also questionable. China built its 35,000 km of fast-rail network (the Héxié Hào) between mid-2008 and the end of 2019 an extreme example admittedly, but a factor of five does make Australia appear less than industrious.

A Canberra-Sydney fast-rail link could replace much of the present short-haul air travel and, given that take-off occupies a relatively large proportion of travel time, substantially decrease emissions per passenger/kilometre. Emissions could be reduced to near-zero if the fast-rail network were electrified, starting with the Canberra-Sydney link.

A fast-rail network would be very expensive to build, but it would bolster the populations and economies of towns such as Goulburn, Bowral and Albury-Wodonga along the rail corridors and take some of the commuter pressure off Sydney and Melbourne.

Douglas Mackenzie, Deakin