Walking through Centre Square in Philadelphia at dusk used to bring an edge of uneasiness to pedestrians. The site of Philadelphia’s beloved City Hall, a civic icon above ground and a major transportation hub below, this once teaming public plaza became underutilised as a result of a lack of design provocation and public programming. 

In 2014, the city decided it was time for a change.

Developing Dilworth Plaza

The former Dilworth Plaza was transformed into what is now Dilworth Park — a lustrous green space featuring a splash fountain, ice rink, lighting and outdoor dining. Two structural-glass canopies rise from street level to highlight the subway entrances to a revamped City Hall station with new finishes and lighting that brightens the bustling hub.

Beyond physical regeneration, this project fills a civic gap by giving an active space to the public and reinstating a connection between person and place. The Center City district itself has undergone a resurgence of economic activity and livelihood.

Adding interactive public art with Pulse

In addition redesigning the square, Studio Echelman was commissioned to design and implement a first of its kind public art piece — Pulse. In September 2018, phase one of Pulse was revealed, featuring a dynamic line of fog and light that traces the path of the subway below. As the first transit-activated public art piece, Pulse attracts visitors of all ages, and offers a personal interaction with Philadelphia’s transportation infrastructure.

Arup joined the project as lighting designers to specifically address the transition of Centre Square at dusk. Dilworth Park, sitting beneath the grandeur of City Hall, is softly illuminated with adjustable spots mounted high on a display of poles, and the distinctive glass entrances ease people through a transition from night sky to underground station. Integrated handrail lighting provides a warm glow to the entrances and keeps the canopy uncluttered and clear. In the station itself, Arup identified key opportunities for lighting to enhance safety and security in a comfortable and architecturally integrated manner. Lighting is arrayed horizontally across the ceiling to break-up the long connecting hallways, with additional downlighting to spotlight kiosk and transaction stations.

I’ve been collaborating with Arup on many projects but this is the first collaboration where water is the main material we are lighting. This idea that art adds to civic life, that are can bring us together, that we communally create and enjoy is something that has been here in Philly for a long time and now with new materials and new technology it is unfolding in a new way in this century.

Janet Echelman

Revitalising Centre Square

Centre Square has always played an important role in Philadelphia’s history. From its early days as a water pump station, one of the city’s first major public works projects that enabled the citizens to thrive, to the beginnings of the Pennsylvania railroad when it became an integral station on the interstate line. In the 1950s city-dwellers moved to the suburbs and Broad Street Station and the Pennsylvania Railroad struggled to remain relevant as the new electric lines connected the suburbs. When the station closed its doors, Centre Square fell silent. 

When Arup was brought on to design the lighting for Dilworth Park, it was more than a city amenities project. Centre Square needed serious reform and regeneration that would honour its history and reinstate the active public space. Opening in 2014, the park was an instant success. The green space continues to hold programmes day-in and day-out, the splash fountain is alive with laughing children, and the adjacent café is an oasis for mid-day lunches and evening snacks. Workout classes spread across the landscape, and the nights are filled with the sound of live jazz flowing from assembled stages. 

Dilworth Park featuring Pulse
Layers of light above the fog, from fixtures mounted to the existing light poles, add dimensionality and character to further animate the particles.
Dilworth Park featuring Pulse
A line of fog, creating a stunning wall that blasts into the surrounding landscape, is seen racing across Dilworth Park.
Dilworth Park featuring Pulse
As the first transit-activated public art piece, Pulse attracts visitors of all ages, and offers a personal interaction with Philadelphia’s transportation infrastructure.

Lighting the way for public art

The final piece in the park’s puzzle came to fruition in 2018 when Janet Echelman’s art piece, Pulse, opened. Designed not just as an installation but as an integral part of the park itself, Pulse is a tribute to the historic presence of water and transportation at Centre Square that embraces the impact of modern technology. Pulling transit data from the station below, Pulse uses this as a trigger for what happens above ground. A line of fog, creating a stunning wall that blasts into the surrounding landscape, races across Dilworth Park. The line traces the path of the Green Line, chosen for phase one of Pulse. Subsequent phases will emulate other lines that run to and from City Hall.

Our lighting team worked closely with each collaborator to understand the physics and materiality of the fog. Following the fog as it moves along the line, linear LEDs corresponding to the colour of the train line illuminate the Pulse artwork. Layers of light projected onto the fog from above add dimensionality and character to further animate the suspended particles. Finally, we utilised gobos, theatrical fixtures that provide pattern and texture, to create a spectacle of colour and mist that calls passers-by of all ages to pause for a minute and experience the dynamics of a city reborn.

Dilworth Park featuring Pulse
Watch Janet Echelman, artist, speak about her vision for Pulse.