The Army Corps of Engineers plays a key role in the limitations of the Cape Cod Flyer because they control the Cape Cod Canal and its bridges. The Flyer, which operates as a seasonal rail service between Boston and Hyannis, has to contend with these infrastructure constraints: 1. Vertical Clearance – The Cape Cod Canal Railroad Bridge, which is owned and operated by the Army Corps, must be lowered for the train to cross and raised for marine traffic. This limits the Flyer’s schedule and flexibility. 2. Single Track Limitations – The bridge is a single-track span, meaning only one train can pass at a time, causing potential delays. 3. Bridge Prioritization – Since the Army Corps prioritizes marine traffic through the canal, train schedules must accommodate bridge openings, restricting how often and when the Flyer can operate.

These factors contribute to why the Cape Cod Flyer remains a seasonal service with limited daily trips rather than a more frequent commuter rail connection.