THE head of the state government-commissioned study into a railway line to Doncaster doubts it could be built for $840 million because of the large amount of tunnelling that would be required.

''My comment to the government was, if somebody's offering to do it for that [price], then sign them up today,'' said study leader Tim Gosbell, senior principal at engineering consultants URS. ''To suggest that any Doncaster rail line option could be built for only $840 million is overlooking the complexities.''

The report says a rail line could be built along the Eastern Freeway median. Credit:Craig Abraham

The Age reported yesterday that a report prepared for six eastern suburbs councils says a rail line from Doncaster to Collingwood could be built along the Eastern Freeway median for $840 million. If linked to the proposed Melbourne Metro tunnel, it could take up to 100,000 passengers a day.