“The Flirt H2 model, made by Swiss trainmaker Stadler, travelled 1,741 miles (2,803km) on a test track in Colorado, over the course of 46 hours on the evening of 20 March and throughout the night and following day.
The train started the test with a full tank and did not refuel, with drivers from Stadler and Ensco taking it in turns to operate the machine throughout the world record attempt.”

[www.hydrogeninsight.com]

From a previous thread on AP, hydrogen sounds like a costly alternative fuel. But that might not stop Amtrak from trying it.