If British joggers, dog-walkers and cyclists were to put up a statue, it should arguably be to Richard Beeching.

Brought in by Harold Macmillan to make the UK's debt-burdened, loss-making railways viable again, the much maligned chairman of British Rail published his report The Reshaping Of British Railways 50 years ago calling for the closure of more than 200 branch lines and 2000 stations. He quickly became a hate figure, with the axing of the Edinburgh-to-Carlisle Waverley line one of his most controversial decisions, leaving Hawick further from a station than any other town in mainland Britain.

With hindsight, some of Beeching's cuts were expensive errors. The 30-mile northern section of the Waverley line from Edinburgh to Tweedbank will reopen next year.

Yet many had an unintended benefit: they bequeathed a labyrinth of solidly engineered trackbeds to the nation that now form the basis of a growing walking and cycling network. The embankments, tunnels and viaducts that once conveyed trains are now run through and cycled over on two legs and two wheels – 150 miles of the National Cycle Network (NCN) in Scotland is on old railway trackbeds – while station buildings and even rolling stock are being reused in innovative ways. History may ultimately judge that Beeching and the other hatchet men of rail did Scotland a favour.

TUNNELS

There are times when even the most committed cyclist wishes the trains had never left, moments when their fingers are so cold they long for the warmth of a train carriage. Hanging around draughty tunnels in the depths of an Edinburgh spring tends to produce this effect. Right now, I'm pedalling through Rodney Street Tunnel in central Edinburgh with Ian Maxwell of Spokes, the Lothian cycling campaign. "The thing about a tunnel like this," says Maxwell, gamely smiling through his pain, "is that it's colder in here than the ambient temperature and it's channelling the wind into our faces."

He's right. Approaching the tunnel mouth we are blasted by such a violent gust of hail it's hard not to take it personally. Once part of a freight line running to Trinity in north Edinburgh, this cut-through beneath a tricky junction at the end of Broughton Road is an impressive piece of Victorian architecture, but it's like a meat fridge. Oh, to have a windscreen, a travel rug and a flask of tea.

Their refrigerative qualities aside, though, tunnels in an urban setting allow cyclists to escape traffic-clogged streets. Unfortunately, they can be dangerous if not maintained, which is why so many are blocked off.

That is the fate of the disused 910m-long Scotland Street railway tunnel which runs like an artery beneath St Andrew Square to Princes Street. Robert Louis Stevenson wrote that "the sight of the trains shooting out of its dark maw" was of "paramount impressiveness to a young mind", but the tunnel closed in the 19th century. Glasgow's imposing 1200m-long London Road Tunnel, linking Parkhead to Bridgeton, was closed in 1964 but could be reopened in future for rail, as could nearby Bridgeton Cross Tunnel. "The railways in Scotland are now carrying more passengers than in the 1930s," says Glasgow councillor Alistair Watson, former chairman of Strathclyde Passenger Transport. "That would suggest it is an industry ripe for growth."

Edinburgh experienced more line closures under Beeching than Glasgow and its rail infrastructure has been widely appropriated for cycleways, including tunnels like the one on NCN Route 75 in Colinton. Here, the rush and babble of the Water of Leith recedes as you climb through Colinton Dell along the top of a high embankment on the former Slateford to Balerno line (closed in 1967). The tunnel's approach is overhung by trees and on a quiet, grey day, its looming mouth looks like the gateway to Ian Rankin's imagination. Cycling into it, that feeling increases at the midway point where, due to its curve, no way out is visible. No wonder suggestible types tend to fly through as if pursued by all the tormented souls of Hades.

Which is all part of the fun, of course. St Leonard's Tunnel is equally atmospheric. At 517m, this cool subterranean passage along the south-west edge of Holyrood Park is so long that approaching walkers look like ants. Built between 1827 and 1830, it was the earliest public railway tunnel in Scotland, part of the horse-drawn coal-carrying Innocent Railway from Edinburgh to Dalkeith and opened as a cycle route in 1981. At rush hour it is as busy as a city centre street.

STATION BUILDINGS

You could be forgiven for trying to buy a ticket at Lochearnhead Scout Station. The last stop on the old Lochearnhead, St Fillans and Comrie line is a painstakingly preserved 1950s station building, and it's easy to imagine a steam train emerging from between the Scots pines. Everything is authentic, from the colour scheme to the information boards, canopy and even the white "safety" line on the 200m platform.

The line was shut in 1959 and the station was acquired in 1962 by Hertfordshire Scouts to give youngsters from the vertically challenged Home Counties an experience of "proper hills", according to Hertfordshire Scouts chairman Alan Rand. Ever since, it has been welcoming parties of Scouts from across Britain. The building contains a dining room for 90 (log cabins in the sidings provide the overnight accommodation), and has a sun lounge with views down Loch Earn.

Numerous passenger routes in the Highlands were opened during the 19th century only to be closed by Beeching. The views across Loch Linnhe from the achingly scenic Oban-Fort William line must have captivated Victorian tourists from the soot-blackened cities of the Midlands, but that romantic journey came to an abrupt end with a sweep of Beeching's pen. Today the route is enjoyed by cyclists. Work is under way on a 32-mile path between Oban and Ballachulish Bridge (12 miles short of Fort William) with the whole route due to be completed next year. Some sections are already open, including the three-mile path between Ballachulish and Kentallen, where the turn-of-the-century station building is now a hotel.

The Holly Tree offers visitors a taste of Victoriana: walk along the interior corridor and you are walking along the platform; relax in the whitewashed wood-pannelled lounge and you are sitting in the original station bar; walk out to the pier and discover where the steam trains met the Oban ferry.

Other station buildings have been made into private homes, cafes, restaurants and rental cottages, but some of the best preserved are museums.

Among them is the Old Royal Station at Ballater. The Royal Deeside Line from Aberdeen, axed by Beeching, was notable for the diversity of its passengers. Heads of state en route to visit the Queen at Balmoral rode alongside day-trippers. Ballater station today has been restored in 19th-century style and visitors can enter a replica of Queen Victoria's luxurious carriage where they can view its quilted walls and voluptuous couches, and peer into the restored Royal Waiting Room before eating in the station restaurant. As for the line itself, it is now the much-loved Deeside Way.

CARRIAGES

The romance of rail can be hard to recreate if you are sharing the Caledonian Sleeper with a snoring accountant from Twickenham. That's why Fiona and Colin Wiseman have so many railway buffs coming to St Andrews to sleep in their garden. A restored luxury railway carriage stands there on original track salvaged from the Fife Coastal Railway (closed in 1965). Inside are two surprisingly spacious suites with bedrooms, shower rooms and lounges, all framed by the carriage's oval roof. Slumming it this is not.

The nearby house is old Stravithie Station, part of the Anstruther and St Andrews railway, and the lounge and library decor so faithfully echoes the station's heyday that one really ought to be wearing tweed. Six further guest rooms are situated inside the building and breakfast is served on the old platform, now enclosed by a conservatory. "I believe it is the only original station building left in Fife, or so railway buffs tell me," says Fiona, though she adds that the carriage was brought up from England.

Up at Loch Awe, another traditional railway carriage has been made into a self-catering holiday coach. Built in 1956, it ran on the London-Edinburgh line for many years before being made into a "tea train" in the 1980s. Sitting on the edge of the still-operational West Highland Line (Loch Awe station was closed by Beeching in 1965 but reopened in 1986), it retains many original features, including bench seats with 1930s upholstery and an internal corridor running alongside the two bedrooms. It is owned by Daniel Brittain-Catlin, a BBC editor and railway enthusiast. Brittain-Catlin, who lived for 16 years in a former carriage in the north of Scotland and also runs picturesque Dunrobin Castle Station in Sutherland as a museum, says, "I cannot see a bit of stranded railway architecture or asset without wanting to save it."

Railway carriages are popular with young fans of Thomas The Tank Engine. If Loch Awe is booked, you can always head up to Rogart in Sutherland and stay overnight in one of six converted railway carriages at Sleeperzzz (Fat Controller not included).

VIADUCTS

Some of Beeching's leftovers stand unused as monuments to the lost age of rail, including the Morgan Glen viaduct over the River Avon south-west of Larkhall, which at 45m is said to be the highest railway viaduct in Scotland. Opened in 1904 by the Caledonian Railway Company, it fell out of use in 1964 and is now B-listed and closed to the public for safety reasons. The mighty steel bridge is a major landmark, but there are currently no plans to restore it.

A variety of other viaducts remain very much in use, however, including the picturesque granite-clad, 12-arch Glen Ogle viaduct, on the former Callander and Oban Railway. Much of the railway bed has now been incorporated into the Rob Roy Way cycling and walking route. The 160m-long, elegantly curved Glaisnock Viaduct near Cumnock, East Ayrshire, was closed in 1964 but is today well used by pedestrians, as is the imposing 11-arch North Water viaduct near Montrose, and Cullen viaduct in Moray. In the south-west, cyclists have since 2008 had use of the handsome red sandstone Queen Of The South railway viaduct over the Nith. Originally on the Maxwellton Railway Line, which Beeching closed in 1965, it now forms part of a 2.5-mile cycle corridor connecting north-west Dumfries to the NCN7 cyclepath, and features the Dumfries Portrait Bench with its sculptures of local heroes Kirkpatrick Macmillan, inventor of the bicycle, JM Barrie, author of Peter Pan, and Jean Mundell MBE, founder of the charity Food Train.

HERITAGE RAILWAYS

In 1969, anger about the closure of the Waverley Line spilled over into a midnight protest by the otherwise mild-mannered people of Hawick. "I was there on the crossing that night," recalls Fred Landery of the Scottish Railway Preservation Society. Landery, from Hamilton, had gone with a group of friends to photograph the last train on the line when rumblings of something big reached his ears. "We heard there was going to be a protest at Newcastleton and right enough the whole village was there, hundreds of people standing on the level crossing, which overwhelmed the local police so they had to call in reinforcements."

Leading the protest was an indignant minister who was arrested for refusing to get off the line. When the sleeper arrived en route to St Pancras it was forced to stop, but on board was a young David Steel (the local MP who would later lead the Liberal Party), who got out and negotiated with the police, persuading them to release the minister. Though the crowd eventually dispersed, the injustice of the line closure was never forgotten.

Forty-four years on, the Waverley Line is being partially rebuilt, but the Waverley Route Heritage Association, a group of energetic enthusiasts, wants to go further. It has established a short portion of heritage railway starting at Whitrope, with the long-term aim of reaching Carlisle. "The timescale depends on the availability of two things: labour and money," says chairman Roy Perkins. "We have 20 or 30 people in the association and do all of it ourselves."

Similar efforts are going on all over the country. Royal Deeside Railway near Aberdeen is a one-mile stretch of heritage line running trains west of Milton of Crathie, heading for Banchory. The 10-mile Strathspey Railway – a route closed by Beeching – has been running diesel and steam trains since 1978 from Aviemore to Boat of Garten and since 2002 to Broomhill, while the Whisky Line, another Beeching closure, is an 11-mile stretch linking Dufftown and Keith in Moray.

Why should all this industrial heritage have such resonance, 50 years on? "The railway was deeply enmeshed in the community," says Brittain-Catlin. And – though its use has changed – so it remains. n

Visit hollytreehotel.co.uk; lochearnheadscout station.org.uk; royal-deeside.org.uk; theoldstation.co.uk; scotlandrailholiday.com; sleeperzzz.com; wrha.org.uk; strathspey railway.co.uk; keith-dufftown-railway.co.uk; deeside-railway.co.uk; and www.srps.org.uk.