@vraiment555 The push for that begins in the 2010s as Colorado becomes a blue state and transplants from the east coast and California start asking why they can't take the train from Denver to Kansas City and St Louis and Chicago and SLC.

@vraiment555 It's a big YIMBY thing now and a lot of federal money has been thrown at it. For political reasons the line splits at Denver, with a northern spur heading to San Francisco via Salt Lake City and Reno and Sacramento while the southern spur hits LA via Colorado Springs and Vegas.

@vraiment555 Eventually the plan is to build a 2nd transcontinental line from Las Vegas to El Paso via Phoenix and Tuscon which then heads east to San Antonio where it joins the Texas Triangle HSR network that opened in 2014 and now connects to New Orleans and OKC.

@vraiment555 Later on, the Denver->Colorado Springs spur of the Denver<->LA transcontinental line is extended south to El Paso via Pueblo, Taos,Santa Fe, and Albuquerque. It's largely considered a pork project and ridership never materializes, but the views are absolutely spectacular.

@vraiment555 Eventually it extends north through Fort Collins to Cheyenne and Rapid City. The full trip from the Black Hills to the Chihuahuan Desert takes 11 hours but is extremely popular with tourists.