This bill, known as the Public Transit Crime Prevention Act, introduces new federal criminal offenses within title 18 of the United States Code to address crimes on mass transportation systems. It specifically prohibits acts of vandalism and graffiti against transit vehicles, facilities, or property, including the possession of tools intended for such defacement. The legislation also makes it a federal crime to assault transit workers while they are performing their duties or to assault passengers on mass transportation. These offenses apply when the transportation system affects interstate commerce or receives federal funding. The bill establishes a tiered penalty structure for these crimes. For vandalism and graffiti, offenders face up to 5 years imprisonment, with aggravated offenses (damage over $1,000 or repeat offenses) carrying up to 10 years and mandatory restitution. Assaults on mass transportation carry a minimum of 5 years and up to 20 years imprisonment for simple assault, while aggravated assaults involving dangerous weapons, serious bodily injury, or prior convictions mandate a minimum of 15 years and up to 20 years imprisonment.