Amtrak knows where it needs to spend money to modernise its busiest passenger rail route — now it just needs Congress to appropriate the funds.

The US national passenger railroad identified five “complex, multi-year projects” that “are critical to keeping people, the economy and the nation moving forward,” said Amtrak co-CEO Wick Moorman.

These include major investments in Chicago’s Union Station in addition to stations in the Northeast Corridor, Amtrak’s busiest region.

Amtrak also called for funding the construction of a new rail tunnel under the Hudson River that would serve New York’s Penn Station, replacement of the ageing Portal North Bridge in New Jersey and the Susquehanna River Bridge in Maryland to improve trip times (partly by eliminating the need to open the bridges for maritime traffic), and replacing the narrow, Civil War era Baltimore and Potomac with a new, high-speed, four-tube tunnel.

Planning and regulatory reviews have already commenced on these five projects. The Hudson River tunnel, with an estimated cost of $13 billion, is seen as especially critical.

The tunnels, along with the Portal Bridge and adding new tracks at Penn Station, are part of the Gateway project, considered one of the most important infrastructure initiatives in the US.