A key block of California lawmakers is feuding with the Biden administration over the state’s high-speed rail endeavor, arguing that conditions of a restored federal grant lock the project into what it sees as an outdated technology for powering the bullet train.

In a recent letter to U.S. Transportation Secretary Pete Buttigieg, California Speaker Anthony Rendon and 17 other Assembly Democrats say the federal grant unnecessarily directs California to use overhead electrical lines to propel the trains down their tracks.

Instead, Rendon wants California to keep open the option of powering locomotives with batteries or fuel cells, arguing that the switch could help the state avoid the high cost of installing overhead lines, a system used worldwide since the 1960s.

The Rendon letter — sent to Buttigieg late last month — comes amid an increasingly intense standoff between Gov. Gavin Newsom‘s administration and the Assembly leader on design and funding for the nation’s largest single transportation project. Newsom wants California to stick to his plan of building the first segment of the high-speed rail line in the Central Valley, but Rendon and his Assembly allies want to divert the funds to bullet train segments in Southern California and the Bay Area, and fears installation of electric lines will close off that prospect.