One of the few - some say the only - positive legacy of the 1992 Universal Exhibition in Seville is the 471 km high speed train, known by its Spanish acronym AVE, which also means bird.

AVE, linking Madrid with Seville in under 2-1/2 hours, was astronomically expensive and tarnished by corruption and bribery allegations. It was highly controversial because many believed such a high-tech transportation system should have first linked Madrid to France's highspeed TGV system through Barcelona or Irun. Some believed it should have relieved congestion along the crowded Madrid-Zaragoza-Barcelona corridor.

But the critics were wrong. It is fantastically successful, with sleek silver and blue bulletnosed trains racing in each direction at speeds close to 300 kph virtually every hour. It is one of the world's most punctual trains: 99.84 per cent of vehicles arrive on time. The national railway company, RENFE, offers a full refund on tickets if the train is more than five minutes late. It rarely pays out. It is the envy of railway firms across the world. Some 5.5 million passengers used the Madrid-Seville AVE last year - many using it as a commuter service. Only 384,000 travelled to and from Seville by rail before 1992. Fewer than 20 per cent use the plane, and RENFE says most of these are travelling on by air to other destinations. Businessmen travelling regularly to Madrid or to Seville no longer stay overnight in hotels or in apartments: they can use the railway, work on the train, keep their appointments and return home each evening.

A decade after the first highspeed train made its inaugural trip, work has finally begun on lines to Barcelona and Valencia, with a branch to Alicante, to the east. Studies and preliminary work have already started on a line north to Valladolid and Salamanca and eventually to Irun.

The journey from Madrid to Barcelona will be halved to 2-1/2 hours, and passengers will be able to travel to Valencia in under 1-1/2 hours. There has been keen competition from cities and towns along the proposed routes for the new AVE to call there.

They look with envy at the small industrial city of Ciudad Real, 200 km from Madrid, where AVE trains halt briefly. Pre-AVE the rail journey took just more than three hours, with only six trains in each direction a day. Now there are 46 daily and the journey takes just 50 minutes.

The AVE has been a lifesaver for this once sleepy city. It has suddenly become an attractive prospect for industrial investors taking advantage of lower property prices. New factories, offices and homes for the workers have sprung up in and around the city. Many commute to and from Madrid and students can live at home in Ciudad Real while studying in the capital.

The AVE runs on the standard European 1.43 m gauge, while all other Iberian peninsula trains run on a wider 1.67 m gauge. The new line will mean the purchase of hundreds of hectares of land, much of it in private ownership, before work can begin. Already property prices along the new routes have risen spectacularly, for the track itself and also for speculators and developers who see business possibilities. When the historic city of Segovia, north of Madrid, is less than 25 minutes away, instead of the present 1-1/2 hours, it will become an attractive dormitory town prospect. Although there has been no decision on whether to route the line through Segovia, land prices have already increased from 100 pesetas (60 cents) a square metre to as much as 1,000 pesetas.

Likewise, when the Barcelona-Girona route is completed, the Costa Brava resort towns, where many Catalans have holiday homes, could well become their permanent residences.

Engineers have to blast tunnels through mountains and build bridges and viaducts over valleys. They will also have to construct tracks and stations to meet the new gauge. There has been considerable opposition from environmentalists, who warn of the effects of such massive construction work on ecologically sensitive areas. Owners of homes overlooking the new lines complain their peace will be disturbed. Their struggles, and possible legal action, will continue as work progresses.

The Madrid-Seville AVE was, after the Channel Tunnel, the biggest civil engineering project in Europe. The new projects will surpass both. The first part of the Madrid-Zaragoza leg should be completed by next year, with the final leap to Barcelona in 2004, and the Madrid-Valencia route a year later. Many dubbed the first AVE "more a white elephant than a bird", but few criticise it now.