One of the start-ups trying to make Elon Musk’s Hyperloop a reality just lost its co-founder and Chief Technology Officer.

Hyperloop One, a start-up competing with Hyperloop Transportation Technologies to release the first Hyperloop, confirmed to Tech Insider that co-founder and CTO Brogan BamBrogan is no longer with the company.

“Co-founder and CTO Brogan BamBrogan has decided to take a step back from Hyperloop One,” Hyperloop One said in the statement to Tech Insider “We appreciate everything that he has done to put us on the path to creating the world’s first Hyperloop.”

BamBrogan is now only listed as co-founder on the Hyperloop One website.

BamBrogan served as interim CEO before Rob Lloyd, the former president of Cisco, took the role. BamBrogan then shifted to the role of CTO.

Recode also notes that Afshin Pishevar, chief legal officer and brother of chairman Shervin Pishevar, has been removed from his post. That change is reflected on the Hyperloop One website.

Hyperloop One completed its first test run outside of Las Vegas, Nevada in early May. The start-up aims to build the high-speed propulsion system by 2020, You can watch the test here: