The objective of this NSF Civic Innovation Challenge (CIVIC) Stage 2 project is to explore and demonstrate an alternative model of rail transit development that revitalizes underutilized—or “legacy”—rail through partnerships. Rail transit in the United States faces several challenges that drive up costs and delay implementation: technical complexity requiring expensive signaling and inspection systems, complex regulatory hurdles, rigid funding structures that limit financial innovation, and reliance on costly feasibility studies to justify demand. These barriers reinforce high-cost, consultant-driven development models that discourage scalable, community-responsive transit. Rather than relying on billion-dollar rail projects, the project team asks: What if transit could start small, grow with demand, and be shaped by the people it serves? The project centers on how legacy rail can overcome barriers that inflate revitalization costs by combining modular rail technology, onboard sensing for safety and maintenance, new regulatory pathways, and grassroots planning. To achieve this, it brings together a partnership of eight organizations, led by Carnegie Mellon University, Pop-Up Metro, and the Delaware River Waterfront Corporation. Through this partnership, the project deploys and operates a full-scale metro along 1.61 miles of legacy rail along Philadelphia’s Delaware River. The demonstration showcases a scalable, cost-effective transit model, with replication in other communit