The Amtrak Grant Flexibility Act would allow Amtrak to use Federal grant funds it receives to cover the non-Federal share requirements for three major Federal grant programs: National Infrastructure Project Assistance Grants, Consolidated Rail Infrastructure and Safety Improvements Grants, and Federal-State Partnership for Intercity Passenger Rail Grants. Currently, Amtrak typically must find separate funding sources, such as its own revenues or state contributions, to meet these matching requirements. Under this bill, Amtrak could use grants designated for one purpose to fulfill matching obligations for another grant program, as long as Amtrak is actively involved in the project beyond just providing money. The legislation applies flexibly depending on the grant type—for example, allowing Amtrak to use National Network grants to match Northeast Corridor projects and vice versa. This change would make it easier for Amtrak to secure Federal funding for rail infrastructure improvements without depleting other funding sources.