Two engineering studies released this summer put the cost of an Austin–San Antonio passenger rail link at two very different figures: nearly $1.9 billion to add trains on Union Pacific's existing freight corridor, or $13.5 billion for a new, mostly elevated line along State Highway 130 and Interstate 10.

Both studies were prepared by engineering firm HNTB. TxDOT published its corridor study in June, examining the addition of passenger service to Union Pacific tracks. Travis County released the second study this week — a 62-page technical memorandum that cost almost $125,000 — assessing whether a new railroad could be built along SH 130 and I-10.

The corridor today carries one daily Amtrak Texas Eagle round trip, a service that arrives on schedule just 56% of the time, according to Amtrak's host railroad report card.

The Union Pacific option

On paper, the shared-corridor concept is the affordable one. TxDOT studied running up to eight round trips a day between Austin and San Antonio, with intermediate stops in New Braunfels and San Marcos. The most ambitious scenario would require almost $1.9 billion in new tracks, signals, stations and other infrastructure, with annual operation and maintenance costs that could top $61 million.

The study carries a major limitation: Union Pacific declined to participate. TxDOT instead relied on federal data and "engineering judgment" to model how passenger and freight trains could share the railroad.

Union Pacific is now disputing the study's premise. "Past efforts have found the existing freight corridor is not sufficient to accommodate both freight and passenger demand," spokesperson Robynn Tysver told KUT News on Thursday. "We believe that is still the case today and we are focused on serving our customers and taking trucks off the state's congested highways."

That statement came hours after Travis County Judge Andy Brown told KUT that, based on earlier conversations with the railroad, he understood Union Pacific could be willing to negotiate again if officials identified a real source of funding. Brown still called the Union Pacific route "probably more realistic in the short term" because of its lower cost and its ability to serve the communities between the two cities.

The SH 130 alternative

The Travis County study avoids the need for Union Pacific's cooperation but introduces other constraints. HNTB estimates that nearly 54 miles of the roughly 90-mile route would have to be elevated. The $13.5 billion figure — which does not account for inflation — includes a 45% contingency cushion.

The estimate covers $360 million for six trainsets, each with two locomotives and three coach cars, plus a $300 million operations and maintenance facility. It assumes minimal highway reconstruction or land acquisition and excludes interest on any potential debt.

Operations would cost an estimated $140 million to $190 million a year. The study did not forecast ridership, so it cannot say how much fare revenue would offset those costs. The route would begin at Austin-Bergstrom International Airport and bypass the biggest population centers between Austin and San Antonio.

A long history of studies

The corridor has been studied repeatedly without producing a train. By 2016, the Capital Area Metropolitan Planning Organization had counted 24 studies on Austin–San Antonio commuter rail since 1997. The Lone Star Rail effort spent about $23 million in state and federal money before Union Pacific ended its agreement with the rail district a decade ago.

Brown argues the political climate has shifted, citing support from county judges, TxDOT's renewed interest in passenger rail and conversations with state lawmakers and U.S. Sen. Ted Cruz.

For now, neither path is funded. One requires Union Pacific to reverse a position it restated this week; the other requires billions of dollars that no entity has committed, leaving officials to weigh a lower-cost corridor they do not control against a $13.5 billion alignment that skips the cities in between.