Hello Xkazx
Welcome to the SBB Community. This is a frequent question on our platform.
The line has been severely damaged this summer after heavy rain, that has provoked floodings and mudslides. The entire Brienz train station was buried under mud, part of the line cannot be used currently and must first be rebuilt.
The reopening is scheduled for the end of September 2024. Until then, buses are replacing the train between Meiringen and Interlaken Ost. This explains why you have to transfer.
Please let us know if you have got more questions.
Kind regards,
Roland