High flyer.

The final phase of Lyons airport's new station is a potent fusion of tectonic prowess and spatial drama, inspired by the great railway sheds of the nineteenth century.

Santiago Calatrava's extraordinary new TGV station at Lyons Satolas Airport is now complete. First considered in these pages as an ambitious project (AR December 1989) and more recently when the vaulted platform structure was unveiled (AR September 1993), the delicate lattice of concrete ribs has now been crowned by the extended wings of the birdlike main hall. That Calatrava's sculpturally expressive (but constructionally complex) conception has now been fully realised is a measure not only of its tectonic potency but also, more prosaically, of the importance attached to new developments by the French state rail system. Unlike other parts of Europe, the Gallic preoccupation with high-speed trains (TGV) and rail networks continues to flourish.

The TGV station at Lyons' Satolas airport in the southern Rhine Alpes region is located on a newly constructed section of track that filters high-speed trains off the arterial Paris/Lyons main line. Politically, the station and its attendant airport are regarded as an important new regional gateway and the bravura quality of Calatrava's new interchange seems commensurate with this increased status.

The main hall is indisputably the most gestural element of the entire composition, acting as a spectacular collection and distribution space for passengers emerging from the sinuous platform vaults below. The bulk of the station is in fact underground, buried in a cutting to the east of the main runway and terminal buildings. (This is to allow for future expansion of the runway network.) Tracks and platforms are enclosed by a 500 m long shallow rib lattice, supported by a delicate skeletal structure constructed from seductively biomorphic concrete. The 50 m wide vault is punctuated by the angular thrusts of the concrete ribs leaping balletically across the tracks. To minimise the number of joints and achieve an appropriately seamless finish, most of the superstructure was cast in-situ, using 25 different sets of steel shuttering to match the intricacies of the engineering design. The steel shuttering was developed from timber prototypes based on Calatrava's preliminary drawings. Each 50 m span consists of two outer units and a central section, the outer units being cast first. Each vault segment rests on the apexes of two triangular supports thrusting up from the substructure. The triangular supports across the middle section of the vault are also tied together at lower level, forming an enclosed box tunnel at the core of the station that contains and islolates the non-stopping high-speed trains that pass through the station at speeds of 300 km/h. The outside tracks are used by trains for the airport, with platforms extending along the length of the vault.

At its mid point, the platform vault is dramatically surmounted by the dihedral wings of the main station hall. After the (albeit agreeable) underground confinement of the bleached ribcage platform vault, the sensation of entering the hall is one of breathtaking, dynamic, light-filled release. The great wings radiate from a central spinal structure, creating a pair of skewed, cantilevering roofs, articulated by a filigree of steel support members. The side walls are fully glazed, suffusing the interior with natural light. It is as if a segment of the vault below had suddenly exploded out of position and frozen in mid air. Yet unlike the swooping, biomorphic fluidity of Saarinen's TWA terminal (with its questing, beaked head), Lyons is an altogether more rigid, hard-edged, almost robotic creation. The decision to use steel, with its attendant constructional complexities, rather than enveloping concrete, perhaps accounts for the apparent stiltedness - although the vaults below are exquisitely organic. The hall links various levels, presenting passengers with a logical and legible circulation system. Escalators lead from the entrance level to a mid-level concourse that extends laterally along the roof of the boxed-in platforms below. Further banks of moving stairs draw passengers down on to the platforms. The best vantage point from which to savour the drama is astride one of the prow-like balcony structures that shoot into mid-air on truncated concrete vaults. Yet despite its magnificent presence and structural pyrotechnics, the 'big bird' is essentially a transit space, briefly uplifting spirits before passengers enact the next stage of their journey, in either the platforms below, or in the airport beyond. And, unlike the great iron and glass railway sheds of the nineteenth century, which embody the historical origins of Lyons' spatial and structural dramas, the new building is a hybrid both in terms of programme (a railway station at an airport) and materiality (steel and concrete).

Crowned with an epic monument to the strangely enduring romance of air travel (despite the fact that most airports and aeroplanes are generally thoroughly disagreeable places), Calatrava's fantastic hybrid is a bold, if occasionally overwrought, attempt to restore some dignity and excitement to the modern travel experience.