Karolis Sankovskis, deputy chairman of the supervisory board at RB Rail, confirmed this to BNS.
Sankovskis said Rubesa's resignation, which came about a month before the expiry of her term of office, was unexpected but posed no risk to the continuity of the company's activities.
"That resignation came ahead of time. Nobody knew about that. It is a certain surprise for us, too," Sankovskis said.
"Anyway, there is no impact on the continuity of the company's activities. Ignas Degutis, the company's CFO and a member of the management board, has been appointed as acting CEO by the supervisory board," he added.