LOTUS is a successor to OMSI series. Nothing much is known about it. It has been in development for ages.
LOTUS includes all means of transport in one game: O like Omnibus, T like Tram, S like Suburban Train, U like Underground - and even related transport carriers. The L stands for headquarters, which translates to Leitstelle in German.
(From what I know they plan to release them in modules, release will include bus and tram modules)
Lotus development progressmap: https://www.lotus-simulator.de/index.php?progress-en/