Answer the following question: Question: "Trains operate on what located on tracks built on the ground?"  Context: "The Farmington Canal Trail is a rail trail that will eventually run continuously from downtown New Haven to Northampton, Massachusetts. The scenic trail follows the path of the historic New Haven and Northampton Company and the Farmington Canal. Currently, there is a continuous 14-mile (23 km) stretch of the trail from downtown, through Hamden and into Cheshire, making bicycle commuting between New Haven and those suburbs possible. The trail is part of the East Coast Greenway, a proposed 3,000-mile (4,800 km) bike path that would link every major city on the East Coast from Florida to Maine."  Answer:
Answer:
rail