Co-founder of Los Angeles-based transportation firm Hyperloop One, Brogan BamBrogan, has stepped down as chief technology officer of the company. Former senior vice president of engineering Josh Giegel will step in to fill the role. The reasoning behind BamBrogan’s departure remains unclear. 

While BamBrogan will retain his co-founder title, he will reportedly not participate in day-to-day operation of the company going forward. According to a report by Recode, Giegel has joined the board at Hyperloop and has been named co-founder and president of engineering.

Hyperloop One has made significant changes to its legal team, with Afshin Pishevar leaving his post as chief legal officer. His replacement Marvin Ammori has been promoted to general counsel following the departure.

BamBrogan joined Hyperloop One from its inception leaving behind a head engineering position at SpaceX to serve as interim CEO until the company hired former Cisco executive Rob Lloyd.