Here is a list of all US transport mega projects (according to Wikipedia and projects I can think of) and their costs, rail projects are marked in blue:
- Alaskan Way Viaduct replacement tunnel - 3.1 billion dollars
- The Big Dig in Boston - 24.3 billion
- Brightline West - 10 billion
- California High-speed Rail - 100 billion
- Chicago Region Environmental and Transportation Efficiency Program - 4.6 billion
- CTA Red Line Extension - 3.7 billion
- Cresent Corridor Expansion - 2.5 billion
- East Side Access - 11.1 billion
- Evergreen Point Floating Bridge - 4.56 billion
- Gateway Program - 16 billion
- Hampton Roads Bridge–Tunnel expansion- 3.9 billion
- The Interstate Highway system - 500 billion
- John F. Kennedy International Airport Redevelopment - 19 billion
- LaGuardia Airport Project - 8 billion
- LAX renovations - 14 billion
- Newark Airport Terminal A - 14 billion
- O'Hare Modernization Plan - 8.8 billion
- Ohio River Bridges Project - 2.3 billion
- Project Connect in Austin - 7.1 billion
- Puget Sound Gateway Program - 2.38 billion
- Reagan Airport’s Project Journey - 1 billion
- San Francisco International Airport Redevelopment - 2.4 billion
- Eastern span replacement of the San Francisco–Oakland Bay Bridge - 6.4 billion
- Second Avenue Subway - 17 billion
- DC metro Silver Line - 6.8 billion
- MTA purple Line - 10 billion
- Sound transit 3 - 50 billion