"The work is meant to be a landscape of the mind. Seeing these super-bright neon colors can be a surreal experience. It will allow people's minds to wander in their everyday life," Thomas said.
Each site will be spray-painted with bright neon strokes blending into one another. Grosse and Thomas will use environmentally friendly paint in bright colors and a team of eight installation artists: six locals and two from Germany.
Work on the project begins Monday, and the artists aim to finish in mid-May. Passengers on Amtrak between Philadelphia and New York, SEPTA's Chestnut Hill West and Trenton lines, and NJ Transit's Atlantic City Line, which combined carry 34,000 passengers daily, will be able to see the work go up - and slowly fade.
The artists will not affix any sealant to the surfaces they paint because the installation is meant to be temporary.
They don't know how long the paint will stay, but they hope it sticks until at least October. When the trees grow leaves and when their leaves fall, it will change what psychylustro looks like, said Nathaniel Lee, a staff artist at the Mural Arts Program.
And that's exactly the point.
"That corridor has a lot of things operating on it - economic development, natural cycles, as well as human intervention. This piece will be one more layer of activity and change," Thomas said.
The Mural Arts Program partnered with Amtrak, which owns most of the property along the five-mile stretch. Amtrak will put informational pamphlets about the program in seat pockets of trains on that route.
Thomas and others in the Mural Arts Program have for a while been following Grosse's contemporary artwork, which is known for its use of color and spray-paint guns, and concluded her style fit with what they envisioned for the project. The $300,000 project received funding from the Pew Center for Arts and Heritage and from the National Endowment for the Arts.
Asked why they chose Grosse rather than a local artist, Thomas said, "We have seen Katharina's work around the world. When one is making a choice about artists, it's not about fame, per se, but about who is really leading a conversation . . .. This isn't just a project for Philly; it's a project for the world."
Although parts of the installation will be visible from nearby highways and to pedestrians, psychylustro is meant to be viewed from a train window.
"These riders see a pretty dreary landscape as they go through Philly. All of a sudden, they'll see 400 to 500 feet of color in the middle of the dreary landscape," Lee said. "It'll make for some great conversation on the trains."