Greater Melbourne is full of relics like these, a reminder of an age when the city was smaller, yet the rail system larger. When The Age ran a series on the city's public transport woes recently, a few readers called for these long-abandoned lines to be re-opened. Some could be, according to transport experts, but, in most cases, the commuter's loss will remain the trail walker's gain. "In terms of the number of kilometres of rail reservation in metropolitan Melbourne, it's certainly true that we've got less now than we had in the past," says Paul Mees, a lecturer in transport at Melbourne University. "Melbourne would build a railway to just about anywhere back in the 19th century."

Probably the most famous abandoned line is the 20-kilometre outer circle, a cross-town route joining the Oakleigh and Fairfield lines. It was originally designed to be a bypass route but, when the need for it fell away, the government went ahead with it anyway, figuring it would cater to suburban growth. Unfortunately, the 1890s depression meant the growth never happened. So few passengers used the railway that it was shut in 1897, less than seven years after it opened. Over the decades parts of it were re-opened, then shut for good, although the section from Camberwell to Alamein survives today for passenger traffic. Passenger trains ran from East Camberwell north to Deepdene until 1927, goods trains as far north as East Kew until 1943. Goods trains continued to use a short section of the Fairfield end, a siding for the Australian Paper factory, until 1993.

"The one all the historians like to talk about is the outer circle, because it was such an extravagant idea," says Mees. "It by-and-large linked places that people had no great demand to travel between, not even now, 120-or-so years later." Once overgrown scrub, the route is now paved. Walkers can stroll its entire length, including the lush Ashburton and Deepdene cuttings, the embankment at Kew, and the Yarra bridge, which now carries cars. North of Heidelberg Road, the Australian Paper siding tracks have only just been pulled up.

"It's just interesting the way it contrasts the different suburbs all the way from Fairfield right across to downtown Oakleigh," says Railtrails Australia secretary Damian McCrohan. "A huge contrast in suburbs there. And there's always somebody in sight on the outer circle. It's just a steady stream of people." Built in 1888, the fourkilometre inner circle line, which ran through Carlton and Fitzroy, was another cross-town route, linking the Upfield and Epping lines. But, unlike the outer circle, it was not an extravagance. Until 1901, it was the only way Eppingline trains could enter the city: the direct route, from Victoria Park station to Flinders Street, had not been built. Nevertheless, after 1901, passenger trains - steam and electric - continued to run to North Carlton and North Fitzroy stations, via Royal Park on the Upfield line, until 1948. Goods trains ran to Fitzroy, on a branch off the main Inner Circle, until 1981. Fitzroy station itself, where the Edinburgh gardens are now, closed to passengers in 1892, nearly a century earlier.

The inner circle's passenger business died, says Paul Mees, because the competing tram service offered a direct route into town. Who wants to travel from North Fitzroy to the city via Royal Park? "It was kept going for a long time but it didn't change the landuse sufficiently to justify itself," he says. Because it was once electrified, and carried goods trains until recently, there's more of it left. "There's more infrastructure there, with the old station in Carlton and the transformer buildings and a bit of rail at one spot," says McCrohan.

Unfortunately, of the sevenkilometre Rosstown railway, nothing remains. Another crosstown route, it ran from Oakleigh station to Elsternwick, on the Sandringham line. It was built in the 1880s by businessman William Ross to take sugar from his sugar beet mill in Carnegie (then Rosstown) to the Melbourne ports. Sadly, his mill failed just after the line was built. Only one train is believed to have run, in 1888. By 1924, the land had been sold. "That's one of the ones the least trace remains of," says Mees. "If you look in the street directory you'll see a number of thin parks around Elsternwick and Ormond that enable you to see where it went." "It's got a great history but it's more a walking tour; it's definitely for history people, I think, that one," says McCrohan. "There's no great cycling pleasure in doing it ... you're just riding down streets; apart from one part where there's a bit of original alignment."

A number of short branch lines have also been chopped off. St Kilda to Windsor, says Mees, was closed in 1859; nothing remains of this alignment today. For decades, trains ran to Springvale Cemetery and Mont Park asylum; these lines closed in 1952 and 1964. The Kew line, which branched off from the Box Hill line at Hawthorn, closed in 1957 and its two stations were demolished. There is a short walking trail to the site of Barker station, now the site of a motor inn. On the site of Kew station itself - with "delicious irony" says Mees - is Vicroads' main office, with the rest of the alignment the office driveway. In the outer suburbs, the Mornington and Healesville lines - both closed in the early 1980s - are now tourist railways for steam trains, although only parts of each line are of operating standard. The seven-kilometre Red Hill line, which branched off the Stony Point line at Bittern, shut in 1953; the 38-kilometre Warburton line, which branched off from Lilydale, shut in 1965. Both are now walking trails.

"That's incredibly popular, the Lilydale to Warburton trail," says McCrohan, who rides with his family along the route. "It's close to Melbourne, with fantastic scenery, and lots of towns along the way - Mt Evelyn, Woori Yallock, Yarra Junction. It's just that right distance from Melbourne and the right trail length as well. It's just nice rural scenery, all the way." Despite documents like Melbourne 2030, the suburbs continue to sprawl. Will these lines come back into use? One might, says Mees. What's now called the Epping line used to run all the way to Whittlesea, and the land reservation is still there. The Bracks Government pledged to reopen it as far as South Morang but seems to have reneged on that promise. The Mornington line is another candidate, says Mees, although when it closed the government sold the Mornington station site at the line's end. This was "right at the period when suburban development was proceeding at a very rapid rate", he says. "It's a sad commentary on the shortsightedness of transport policymakers in Victoria, at least on the public transport side of things. You'd never catch VicRoads selling off a road reservation."

Warburton won't see trains again, says Mees, and Healesville's will remain tourist only. "The Upper Yarra Valley is designated as an area that's not supposed to become urbanised," says Mees. A rail service would be a "tremendous spurt to suburban growth". For the same reason, he says, Red Hill won't be reconnected to the network, "with the added element that it is a rather indirect route".

Warburton is Mees' favourite rail trail but, of the ones closer to town, the outer circle wins his vote. "You've got an extraordinary array of terrain, you've got to go underneath some road bridges that bridge over what appears to be nothing, and you cross the (Yarra) river at a particularly scenic point. Although, you don't get much peace and quiet given the motor traffic that uses the bridge these days."