Go Transit - Union Station - Train Roof Shed Rehabilitation


Designed by Zeidler Partnership Architects
Photo by Metrolinx

Union Station in Toronto is the busiest transportation hub in all of Canada. As the gateway to the downtown core, it provides access to various forms of transportation. The train area of the station is covered by a heritage designated structure, built in the late 1920s, and covers eight acres. As part of a complete roof replacement, one acre of the roof will be removed and a translucent glass structure will be built that will float above the existing structure. The construction is to be phased over seven years to maintain operations within the existing transit facility.

The project includes construction and rehabilitation of train platforms as well as the replacement of electrical, mechanical, and low voltage systems throughout the entire Train Shed. The project involved the survey and analysis of the existing heritage facility, developing a custom electrical and mechanical design solution, and the installation of the design including power distribution, lighting, specialty lighting, fire alarm, plumbing, drainage, HVAC, fire suppression, telecommunications, PA speakers, CCTV, PINS, and extensive EMI analysis as a result of the possibility of electrification of the trains through Union Station. A new electrical substation and emergency generator was installed to supply the lighting and systems throughout the Train Shed. Custom light fixtures were designed to match the original 1929 heritage light fixtures and an extensive raceway system was designed to work within the heritage limitations.

S + A Services Included:


The new 6816 square metre by 3 metre high roof / glass atrium built over the passenger platforms and railway tracks posed numerous unique design challenges. The box is essentially a greenhouse that is subject to extreme high and low temperature and humidity levels inside the box while the temperature and humidity outside of the box may be at the other extreme. With the extreme temperature the structure steel members would expand and contract and with extreme humidity, condensation can form on the inside face of the glass enclosure. To mitigate the potential damages cause by the extreme temperature and humidity, the conditions inside the box and the outside ambient condition must reach equilibrium in a minimum amount of time. To achieve this a ventilation/exhaust system consisted of thirty-six 400mm x 400mm roof vents and 12 motor operated windows on the east and west side of the glass box were designed to integrate into the architectural elements. Temperature and humidity sensors inside the glass box were installed to control the motor operated windows. Snow melting/radiant platform heating were installed in the new train platforms located outside south shed roof.


The entire electrical systems for the train shed area has been replaced with a new substation and an emergency generator was installed to supply the lighting and systems throughout the train shed. An extensive raceway system has been designed to service the large area while working within the heritage limitations. The roof of the glass structure has solar panels that will generate up to 300kW of power that will be fed back into the electrical grid, enough to supply the lighting for the entire facility. The area in the glass box will be lit with energy efficient lighting.


Enabling the facility to easily adapt to decades of future technological paradigm shifts was a critical design requirement for this project. An Internet protocol (IP) data network consisting of data switches and a high speed redundant fiber optic backbone utilizing diverse distribution methods was designed. The fiber optic backbone lined a data centre and numerous telecom distribution rooms that facilitate the connectivity and distribution of multiple IP based systems; critical to providing information, safety and security at the train platform level. A structured horizontal cabling system was also designed to facilitate the connectivity between all information, safety and security peripheral devices, and respective telecom distribution rooms.


To aid in providing information, as well as safety and security at train platform level to thousands of commuters on a daily basis, Smith + Andersen designed several features; an Internet protocol (IP) based public information system (PINS) to facilitate real-time display of train schedules via multiple flat panel LCD monitors on each platform. An overhead paging/mass notification system to promote the broadcast of general, critical, automatic, and manual audio announcements at platform level. The design included new, state-of-the-art, digital audio processing headed equipment, integrated with some of the existing page initiating equipment. A closed-circuit television (CCTV) system consisting of strategically placed video surveillance cameras to monitor and record activities on all passenger train platforms.

All security systems were designed to utilize the high speed redundant and diverse fiber optic backbone for connectivity. This resulted in systems with high availability; critical to the operations of a mass transit facility.


Toronto, Ontario

Gross Floor Area

  • 350,000 sq ft

Total Construction Cost

$ 250,000,000

Completion Year



2012 Canadian Architect -