69 corridors, 1 pipeline
In December 2023, the Federal Railroad Administration (FRA) selected 69 passenger rail corridors across 44 states into its Corridor Identification and Development Program. It is the first programmatic pipeline of intercity rail planning the United States has had since the 1960s.
Each corridor gets a Service Development Plan (SDP), which consists of the route's service goals and the capital investments needed to achieve them. Corridors also receive federal funding for early engineering and a path through the federal review process. What none of them gets is construction finance.
Not new rights-of-way
Around 90 percent of Corridor ID routes share right-of-way with active freight lines, many of them strategically important Class I mainlines. The exceptions are a handful of greenfield high-speed proposals (Cascadia, Atlanta–Charlotte, Texas Central) and publicly owned segments like the Northeast Corridor. The U.S. passenger rail revival, to the extent it happens, will happen on freight track.
Six companies own most of it
BNSF, Union Pacific, CSX, Norfolk Southern, CPKC, and CN own 77 percent of the pipeline's route mileage. Amtrak and state-owned segments fill in the rest, concentrated in the Northeast.
Every passenger upgrade on lines owned by the big six has to be negotiated with one of six private actors. Yet 45G is reserved for Class II and Class III railroads. The current rule excludes the actors that own most of the track.
Most routes are still in early planning
The Corridor ID program has three steps: 1) scoping; 2) the Service Development Plan; 3) project development, including National Environmental Policy Act review and preliminary engineering. Federal support runs through all three steps. Then it stops.
The pipeline is still front-loaded. Only a handful of routes (the DC–Richmond–Raleigh S-Line most prominently) have reached Step 3. The cliff between the last federally funded planning step and a competitive grant for construction is where projects stall.
Case study: the Downeaster
Boston to Brunswick today, with a planned extension to Rockland and frequency increases throughout. The MBTA owns the track south of Plaistow. CSX owns the 106 route miles from Plaistow to Brunswick, having acquired Pan Am Railways in 2022. MaineDOT owns the dormant Rockland Branch.
Under the proposed 45G extension, CSX could spend up to $540 million a year before the annual cap binds. That spending would fund electrification of all CSX-owned mileage on the corridor, plus enough double-tracking to bring the line to two main tracks throughout. The full package comes to roughly $2.3 billion over five years. CSX would claim about $185 million a year in credits, comfortably inside its annual cap. The total federal share is around $930 million.
Case study: the Gold Runner
Bakersfield to Oakland and Sacramento via the Central Valley, on roughly 280 miles of BNSF mainline that doubles as one of the country's most important freight corridors.
Assume BNSF's internal cost of about $6 million per track mile, conservative relative to the recent Needles–Goffs triple-track benchmark. A $900 million double-tracking program along this corridor would then draw $360 million in federal tax credits. The claim comes to $180 million a year over two years, well under BNSF's $305 million annual cap. The federal cost is $2.4 million per track mile. Compare Ceres-to-Turlock, ten miles of publicly procured second main track on the same corridor, which came in at $13.3 million per mile. The same public dollar buys roughly five times the track through 45G.
Where the extension matters
The corridors lit up here are the ones where a Class I host owns most of the right-of-way. They are the universe where extending 45G to Class I carriers would unlock new construction funding. The credit would pay only for investments named in an FRA-approved SDP.
Summed across all six Class Is and capped by total network mileage, the investment unlocked comes to roughly $2.8 billion per year. The federal cost is around $1.1 billion a year, the sum of every carrier's annual credit cap. That funding runs indefinitely, requires no competitive grant cycle, and pays only for investment that gets built.
Corridor ID is the planning pipeline. 45G becomes the construction engine.