The last stop of the Meringen-Innerkirchen-Bahn is some distance from the SBB station Meiringen (Brünig line). Despite the track connection between MIB and SBB there is normally no traffic because of the different current systems.
After a third of its length, the line disappears in the 1502 m long Kirchettunnel, the largest construction of the line. It bypasses the word-famous Aare gorge. The last part of the line is in the local area of Innertkirchen, and the final destination is already at the factory area of the Oberhasli power stations.
After the turn of the century plans were made by the Bernese power stations (BKW) to use water power for generation of current in the Oberhasli and at the Grimsel pass. Also a narrow-gauge railway was planned from Meiringen over Innertkirchen to Guttannen. The company Kraftwerke Oberhasli (KWO), founded in 1923, finally built a narrow gauge railway Meringen-Innertkirchen in 1926 for the transport of building materials and workers.
Because of the small population of the valley and for cost reasons the construction of the part Innertkirchen-Guttannen was skipped. Instead a system of funiculars was installed for carrying building material to the different construction places of the concrete dams and power stations.
During the construction of the first power plant the Mallet steam engines G 2/2+2/3 23 "Maloja" and 24 "Chiavenna", taken over from the Rhaetian Railway, have handled most of the goods traffic.
Soon after the opening there was a limited passenger traffic, particularly for the coworkers of the KWO and their families. In 1931 the akkumulator-tractor Ta 2/2 3 with 12 seats was procured. This vehicle is still available on the first German museum line Bruchhausen-Vilsen. For reinforcement in 1939 a somewhat larger akkumulator motor coach CFa 2/2 4 with 22 seats and a goods compartment was procured at SIG/saas.
In 1946 the company received a concession for public traffic from the government. Thus the MIB was founded, which still is owned by the KWO. Because of the rising traffic a second identically constructed CFa 2/2 5 has been put on duty.
With the end of the concession at the beginning of the 1970's they considered changing the type of traction. The rigid fourwheel chassis and the high weight of the accumulators had damaged track and ballast underground severely. Also the electrical mechanisms were close to their end of life. When the concession was renewed in 1976 for a further 50 years, the complete track could be renewed. From the Oberrheinischen Eisenbahn-Gesellschaft (OEG) the KWO bought three streetcar-similar motor coaches from the Oberrheinischen Eisenbahn-Gesellschaft (OEG), Germany, which were built by Fuchs, Heidelberg, and have been used in Mannheim. Two of them were adapted for the MIB in the SBB Brunigbahn workshops at Meiringen, the third was used for providing spare parts. In order to enable the fetching of freight wagons from the SBB station in Meiringen, the so-called railcars Bem 4/4 6 and 7 have an emergency power generator with a Volkswagen petrol engine.
When these two motor coaches started wearing out, the company has hired the BOB ABDeh 4/4 301 (built in 1949) from 1988 to 1996.
In March 1996 the MIB received the first vehicle fresh from the factory after 50 years: The Be 4/4 8, built by Stadler/ABB. The old Bem No. 7 remained as a reserve and No. 6 was used for providing spare parts. Finally No. 6 was scrapped in the year 2000.
As a new reserve the MIB has bought the Be 4/4 74 from VBW (Vereinigte Bern-Worb-Bahnen) now immatriculated as Be 4/4 9. This vehicle can be watched on duty normally on Wednesdays.
The current timetable contains up to 17 train pairs per day. The goods traffic is handled on demand and consists usually of SBB Brunigbahn wagons with spare parts for the power stations.