ABOARD AMTRAK TRAIN 182 (Reuters) - Amtrak is gearing up to introduce new high-speed Acela trains as it plans to spend billions of dollars in upgrades on the busiest U.S. rail corridor.

FILE PHOTO: Amtrak's high speed Acela at Washington's Union Station Feb. 8, 2011. REUTERS/Larry Downing/File Photo

The national U.S. passenger railroad on Friday gave reporters a tour by train of the busy northeast corridor from Washington to New York, showing off places where the rail system needs upgrades, including an 1873 Baltimore rail tunnel with water infiltration issues that will cost $4.5 billion to replace and the 1906 Susquehanna River Bridge whose replacement is estimated to cost $1.7 billion.

Amtrak carries more than 12 million passengers a year in the corridor that accounts for nearly 40 percent of the railroad’s traffic nationwide. It is spending about $700 million annually to maintain and upgrade the corridor but has long-term needs of more than $30 billion as it seeks to introduce next-generation higher speed service by 2040.

The final cost “depends on what version of the future you want to buy,” said Stephen Gardner, Amtrak’s executive president for planning, technology and public affairs.

Amtrak trains are often delayed because of freight traffic, and aging infrastructure requires slower speeds in many places.

The biggest immediate need is the “Gateway project” that would build a $13 billion rail tunnel under the Hudson River, replace the Portal North Bridge in New Jersey - a source of many trains delays - and rebuild the North River Tunnel that connects New Jersey and Penn Station, among other projects.

Failure of the lines in the current tunnel, which was damaged during 2012’s Superstorm Sandy, could come within a decade and would hobble commuting in the metropolitan area that produces 10 percent of U.S. economic output.

President Donald Trump met with New York Governor Andrew Cuomo in November to discuss the “Gateway” project, but no funding agreement was reached. Amtrak has not identified funding for other large projects.

Many upgrades are aimed at letting trains travel at higher speeds and reducing delays, as well as replacing and resurfacing track and replacing switch panels. The railroad is also upgrading many northeast train stations.

By 2021, passengers in New York City will board trains from Moynihan Station in a new sunlit atrium concourse across the street from Penn Station as Amtrak moves into a larger space with a new customer lounge.

Amtrak is planning to start using new Acela trains starting in 2021. The railroad is buying 28 Acela train sets, eight more than it currently operates, using a $2.45 billion federal loan. It is also planning to buy a new fleet of trains for its slower Northeast Regional service in the middle of the next decade.

Caroline Decker, vice president for the Northeast Corridor Service Line, said Amtrak is considering offering some non-stop trains between New York and Washington that could cut at least 15 minutes off the current travel time.

Amtrak has fended off efforts by Trump to cut its federal subsidies. Last year Amtrak faced questions in the wake of several fatal accidents. Amtrak vowed improvements after the National Transportation Safety Board in 2017 criticized what it termed Amtrak’s “weak safety culture.”