The main purpose of this legislation, known as the Building Rail Infrastructure for a Durable and Growing Economy Act or the BRIDGE Act, is to create a competitive grant program aimed at providing financial assistance for the maintenance, replacement, and rehabilitation of commuter rail bridges. The goal is to improve the infrastructure of commuter rail systems, ensuring they are safe and reliable for public use. Key provisions of the BRIDGE Act include the establishment of a grant program that allows the Secretary of Transportation to award funds to public transportation system operators.