We last met architect Sir Nicholas Grimshaw at London’s Waterloo International Station, the five platforms of which (despite a chronic lack of station capacity at Waterloo) are currently standing empty and unused in a rather shocking failure to get the best out of some significant public sector investment. The roof, you’ll remember, is a particular thing of beauty. Yet it’s a fairly conventional steel and glass roof as things go, while Grimshaw (the architectural practice of which Sir Nicholas is chairman) has latterly become very much associated with a new high-tech glazing technology. That technology is ETFE (Ethylene tetrafluoroethylene) and it can be found being deployed by Grimshaw once again at this week’s transport beauty, Southern Cross railway station in Melbourne, Victoria, Australia.

One of the earliest major buildings to use ETFE was the Eden Project (in Cornwall, UK) where several large domes formed from panels of the material were constructed in an old china clay pit, to house a series of biomes showing off flora and fauna from around the world. It’s since been used on other high profile buildings with the Water Cube National Aquatics Centre in Beijing (not by Grimshaw) perhaps the most famous. But it is Grimshaw that has become something of a specialist with the material, using it at the Leicester Space Centre (UK), Newport Station (UK, where to be even-handed, the roof has had some teething troubles not seen at other ETFE structures by Grimshaw) and the ExCel Conference Centre in London (UK). This translucent plastic film is very light (much lighter than glass), very strong, and lets in lots of light. It is generally used in buildings in the form of inflatable cushions (rather than flat plates of glass). That allows it to take some unusual forms which would be near-impossible to replicate with glass (run an image search of the web for the Leicester Space Centre and you’ll see this in practice). ETFE is also practically stain resistant because it is non-stick. The obvious concern that springs to mind if you’ve got a roof made of inflated plastic, is whether the cushions ever get punctures. Well, yes they do, but all you need to fix them is a bit of ETFE tape and then you’re ready to reinflate them and you’re right as rain again. Which is actually rather more convenient than replacing glass panels, especially the unusually-shaped bespoke ones which are typical of flagship architecture, for which you might be waiting many weeks for a replacement.

But back to Melbourne, where in 2002, the Victoria Government was busy with a state-wide programme of rail investments. The existing station at Spencer Street was forecast to be too small to cope with predicted rises in patronage, so the Victoria Government commissioned its complete rebuilding in a $350m (about £210m) project completed in 2006. Grimshaw designed a beautiful structure for the new station. The key design element is a billowing, silvery roof; the station is open along substantial lengths of its sides, giving it great permeability, with the rest of the walls sporting plain glass curtain walls which allow vision deep into the station (and outwards from deep within it) making it a part of the city, rather than something cut off from it. This photo, taken during construction, gives a good sense of the shape of the roof, and the hard work that went into its design and construction:

The roof is described by Grimshaw as “dune-like” which gives a good sense of the shape of the undulating metal which makes up the majority of its surface (see this image from Grimshaw Architects’ website). At the top of each peak (23m above the ground at their highest)  is a passive ventilator, which draws air from the station to keep passengers cool, and allows exhaust from diesel powered trains to be dispersed. Between each row of ‘dunes’ is an undulating  ribbon of ETFE skylights (see this image from Grimshaw Architects’ website) which runs the length of the roof and allows natural light down into the station. Running under the skylights are curving trusses (the arrangement recalls the roof of Waterloo International, although the orientation has shifted ninety degrees), which are themselves supported by Y-shaped columns:

Covering 14 platforms and with an area of some 60,000m², it would be quite some roof which utilised only the walls for support. The Y-shaped columns are a design element which is repeated in the shape of the lamp columns on the station platforms, and the information display units. The underside of the roof is also interesting, with an intricate origami-like effect of angled surfaces:

Offices within the station are housed within freestanding bright-yellow cuboids, supported on four tapering legs, like a 1970s television set. With chamfered edges and glass fronts, the resemblance to a TV set is even more striking (as you can see in this image from Grimshaw Architects’ website).

At night, a well-considered lighting design adds to the drama of the station. The ETFE  panels are illuminated in purple and the rest of the underside of the roof is illuminated in gold, like the Roman toga picta worn by the Emperor on special occasions, which is rather apt.

The station is still expanding. Two additional platforms have been added in preparation for a new regional train service due to commence operation over the next few years.

There have been the usual moans and groans from some people who don’t like the redeveloped station. In particular, the height of the footbridge used to provide access from the concourse onto the platforms has been criticised for being taller than the old subway (which used to perform the same role) was deep. But escalators and lifts are available to ensure accessibility, and others have been much more positive about the new station design. In particular, in 2007 the station was awarded the Royal Institute of British Architects’ Lubetkin Prize, which each year celebrates the most outstanding work of architecture outside the UK and the European Union by a RIBA member. As well as admiring the “rivers of light” cast by the ETFE glazing in the roof, the judges were particularly pleased that this roof, rather than being a thing of private pleasure for architect or client, was easily admired by people inside the tall buildings which surround the station. They said “it makes a good space beneath and an extraordinary undulating landscape above.”

Here’s a final view.

References and further reading

Grimshaw Southern Cross Station project page, with background and lots of beautiful pictures, here

RIBA’s page on Southern Cross Station’s 2007 Lubetkin Award, with full citation, here

A railway-technology.com briefing on the station, here