During winter weekends in 1976, when he was a University of Toronto architecture student, Tarek El-Khatib would sometimes catch a train from Union Station to spend time with friends in Montreal. He loved train travel but loathed trudging up the dingy and heavily salted stairwells of the Toronto station to reach the damp, dimly lit platforms.
Getting on and off trains at the shed behind Union Station isn't quite the grand occasion one experiences in many European cities where platforms are protected by cathedral-like structures made of iron, steel and glass.
When its platforms were built 80 years ago, Toronto's train shed was shortchanged in the grandeur department - unlike the Beaux Arts-style Union Station building, the largest and most opulent station erected in Canada.
Behind the station, the low-ceiling, wood-and-steel train shed was designed by American engineer Abraham Lincoln Bush to serve freight operations and long-distance intercity passengers, not to impress the tens of millions of commuters who use it today.
By the end of 2014, though, Toronto will finally have a train shed with wow factor. A 5,000-square-metre glass atrium - designed under Mr. El-Khatib's guidance - will be cut into the middle of the historic train shed roof, part of a $196-million renewal plan.
"The idea is that we will ... create a sense of arrival and sense of identity for the station," says Mr. El-Khatib, a senior partner at Zeidler Partnership Architects in Toronto.
GO Transit, a division of Metrolinx, recently awarded the train shed's multimillion-dollar general contract to Aecon Group Inc., a Toronto construction and infrastructure development firm. The train shed refurbishment represents almost one-third the cost of Union Station's massive $640-million, five-year revitalization project. That overall plan includes a new 11,150-square-metre retail concourse; two new GO Transit concourses; and a tunnel connecting Union Station to Toronto's underground PATH system.
The train shed aspect is both a restoration and reinvention of the historic space. The plan calls for retrofitting the east and west sections of the 33,500-square-metre Bush roof with new galvanized steel and replacing the central section with a three-metre-deep, box-like glass ceiling that will appear to float 15.25 metres above the tracks and platforms.
The Aecon contract also includes adding nine passenger elevators and 50 new glass-enclosed stairwells to the platforms, restoring the heritage features on platform 12/13, removing and repairing 4,200 metres of existing track beds, waterproofing at track level to prevent leakage to the concourse below, installing new signalling systems and track switches, upgrading public communications equipment, and installing new roof drainage and snow melting systems.
The 65.4 million passengers who use the station every year will notice the construction, but they won't see any reduction in rail service, says Michael Wolczyk, GO Transit's director of Union Station infrastructure. The trains are already running at capacity, so the station has no choice but to get the work done without cutting service, he says.
"Even if we were able to shut down Union Station and do this work, it would still be a difficult project, but it would go much quicker," Mr. Wolczyk says. "There's a lot going on behind the scenes that people won't see. Every time we do a [train and platform]change, we have to communicate that to customers ... and there is a change to how the trains move in and out of the facility ... it's very highly orchestrated."
The biggest issue for the shed's general contractor is logistics, says Keith Williams, senior vice-president, Aecon Buildings division, Greater Toronto Area. "It's a huge challenge - material delivery, material storage, material handling. Separation of workspace from the public. And safety is absolutely paramount."
The train shed work is particularly tricky. The roof runs east-west and covers 13 tracks and 23 platforms. The plan is to close off two tracks and two platforms at a time, which means the work has to be done in narrow strips measuring about 13 metres wide by 366 metres long. Each strip will take four to seven months to complete. Work will begin at the south end and once a strip is completed, the platforms and tracks will be put back into commission. Travellers will see the space take shape.
"They will be able to look up and see sections of the roof as they are replaced and certainly, the atrium will be a key feature. Not too long in the future, there will be light coming in," Mr. Williams says.
The new north-south oriented glass atrium will be constructed in strips coinciding with the platform work below. "It's actually an engineering feat because, in most cases, the [supporting]columns land on existing footings. When they build the first strip [of the atrium] that line is actually going to anchor the whole [glass]roof," Mr. El-Khatib explains. The glass box will overhang the refurbished east and west roofs where the original industrial steel trusses will be visible. Inside the glass box will be steelwork that echoes, on a larger scale, the Bush shed steelwork.
There will be both transparent and translucent glass panels "so that there is a kind of a play between seeing the steel and sometimes just seeing the shadow of it," he says.
This idea was inspired by the large, arched windows at the east and west ends of Union Station's Great Hall. These windows also act as glass corridors connecting the station's southern and northern wings. "We thought, okay, why don't we take that [design]and lie it horizontally as an idea for the roof," Mr. El-Khatib says. At night, the lit atrium will be reminiscent of London's Tate Modern art gallery, a converted power station with a two-storey glass roof addition.
It's important to the architects, Mr. El-Khatib says, that people who use the station find the new train shed to be a fascinating space.
"We hope that [travellers]will appreciate it that way. ... We are very confident that it's going to be a really elegant piece that will do the station a lot of justice."
The green features of Union Station's train shed project:
The north end of the glass atrium will connect to a restored section of the Bush train shed roof. The underside will show original wood planking, while the exterior will house 914 photovoltaic panels that will feed 148,000 kilowatt-hours of energy per year into the public power grid.
The east and west shed roofs will be outfitted with hardy green plants.
The structure will feature high-efficiency lighting; a building automation system to control HVAC and lighting; Enwave Deep Lake Water Cooling; solar water heating for in-building use; low-water-use plumbing fixtures; a storm-water retention and grey water reuse system; and high-efficiency electrical transformers.
Ventilation of train exhaust will be non-mechanical. The original smoke ducts in the east and west Bush roofs will be restored.