Amtrak has signed a mammoth contract with manufacturing company Siemens Mobility for 83 new train sets, part of a $7.3 billion plan to upgrade its rolling stock over the next decade.

Under the plan announced Wednesday, Amtrak will replace nearly 40 percent of its rail car fleet by 2031 and invest $2 billion in facilities upgrades systemwide. The oldest cars in Amtrak’s fleet would be taken off the rails after five decades of service. The deal marks one of the railroad’s biggest investments in its 50 years of operation and comes as the company is pursuing an ambitious $75 billion expansion to bring trains to dozens of cities and towns across the nation.

Amtrak officials say they hope to have the first of Siemens’s Venture trains operating in 2024 and the entire new fleet in service in 2031, although funding has yet to be secured. Congress, so far, has authorized $200 million for the rail cars. Amtrak says it expects funding from transportation reauthorization and infrastructure bills being debated in Congress.

“This is really the next big piece of our transformational effort for intercity passenger rail across America,” Amtrak President Stephen Gardner said in an interview. “It’s a huge moment for Amtrak, and really, the start of a whole new chapter in terms of Amtrak vehicles.”As part of the contract, California-based Siemens will provide Amtrak with technical support and maintenance for 20 years after delivery of the first train set.

Amtrak also is on track to replace its Acela fleet with 28 high-speed train sets from French manufacturer Alstom. Those trains, part of a $2.5 billion project, are expected to enter service next spring after delays caused by testing, as well as production and training interruptions during the coronavirus pandemic.

Amtrak’s base contract with Siemens, worth $3.4 billion, calls for 73 multi-powered train sets and the service agreement for Siemens to provide support, parts and materials. Railroad officials said another $1.5 billion would include an additional 10 train sets. Amtrak said the deal also facilitates the procurement of 130 trains to support Amtrak’s growth plans.