LEDs are the only stop for a transit station in Chicago that could be an archetype for the future
By Paul Tarricone
A new train station has ushered in a new light source in Chicago. The $75-million elevated Washington/Wabash station opened in 2017, as two century-old stations were consolidated into one. The new station—which saw an estimated 3.2 million passengers in 2018—is also the Chicago Transit Authority’s first all-LED station and should serve as a model for the city going forward. “This is a new gold standard for what a new ‘L’ station should look like,” said then-Mayor Rahm Emanuel.
Local firm EXP designed the station lighting. Their scope of service included lighting of the platform, stairs and handrails, mezzanine and accent lighting. While the LEDs broke new ground for the CTA, it’s the architecture that’s front and center. “The overall approach was simply to express the station architecture as purely as possible without drawing undue attention to the lighting design itself,” says Aram Ebben, EXP principal and director of lighting design. Indeed, the gleaming, modern architecture—from the illuminated handrails to a wave-like glass canopy over the 450-ft-long platform—is juxtaposed against the historic Jewelers Row neighborhood.
To further enhance the architectural expression, the luminaires throughout the station were fully integrated into the physical structure wherever possible, as “to not detract from the clean lines of the structure. This approach required substantial coordination between the CTA, Chicago DOT, lighting designer, architects, structural engineers, electrical engineers, contractors and luminaire manufacturers to ensure that all services and devices would fit within the allotted spaces.”
The central spine of the platform structure is home to drains, data and power conduits, as well as the luminaires themselves, which were recessed to provide even illumination of the custom lenses. The rib-tip luminaires also presented a unique challenge in coordination as they are suspended over active train tracks located on an elevated steel platform. “Like any truly collaborative process, the lighting design evolved through several iterations before developing into the final realization,” says Ebben.
Going all in on LEDs essentially came down to the right technology at the right time. “Timing played a key role in being able to exclusively use LED as the light source,” Ebben adds. “The technology had matured to a point that it would be able to meet CTA and CDOT’s requirements. Certainly, LED fixtures have been slowly incorporated into other CTA station lighting renovations, but this was the first new all-LED station on the LOOP.”
CTA has detailed illuminance requirements for each space that range from 2 footcandles (average) for parking lots, to 20 fc for platforms and stairs to 35 fc in kiosk and customer service areas. The previous CTA master specification and design criteria were based on fluorescent sources. However, since completion of the Washington/Wabash station, CTA has revised their criteria to require 100% LED lighting.
Finally, the control system is fairly simple, Ebben says, as most of the station lighting is required to be on 24/7. Non-regularly occupied spaces are controlled via vacancy sensors. Even though CTA stations are exempt from having to adhere to energy codes, this station maintained close to 1 watt per sq ft.