I plan to travel from Bern to Luzern via Trubschachen so I can visit the Kambly factory. Normally, this route can be done via train, which is covered by the Berner Oberland pass, but there is construction that disrupts the train service from Langnau I.E. to Schüpfheim. The SBB app is showing this part of the trip can be done by bus. Since this bus is a rail replacement service am I able to use the Berner Oberland pass or do I need to purchase separate bus tickets?