BOB, or Berner Oberland-Bahnen is operating narrow gauge (1 m gauge width; network length 24 km, 1500V, opened 1890) trains which use a third cog wheel for the steepest slopes from Interlaken up along the two valleys of the Weisse Lütschine and the Schwarze Lütschine to the villages of Lauterbrunnen and Grindelwald, respectively. Typically the trains start from Interlaken as a combined train, which is then split into two halves at Zweilütschinen, where the two valleys split. Both Lauterbrunnen and Grindelwald are famous ski resort villages and trains of other companies (WAB and BLM) as well as cable cars take skiers further up from them to even more elevated ski slopes.

The BOB service uses a third cog wheel track for the steepest rises. In the middle of the train a second locomotive or EMU is often used as the trains are usually split in two halves at Zweilütschinen. Here the BOB EMU type ABeh 4/4 no 311 as a "middle locomotive" on its way to Grindelwald and Lauterbrunnen. In those days when this picture was taken, BOB's trains still used to be dark brown and creme. Later a new livery in dark blue and creme has been taken in use. Photo from the Wilderswil station in May 1999 by Ilkka Siissalo. Uploaded May 24, 1999.

A closeup of the Berner Oberlandbahn BOB Abeh 4/4 2. series EMU no. 311 in the middle of a train to Grindelwald and Lauterbrunnen at the Wilderswil station. BOB ordered three of these new series ABeh EMU´s in 1986. It´s built by SLM and BBC, it weighs 45 tonnes and its maximum speed is 70 km/h on normal and 35 km/h on cog wheel tracks. Notice the small first class passenger department marked by a yellow line over the window.
Photo by Ilkka Siissalo. Uploaded May 24, 1999.

ABeh 4/4 2.series number 313 of the Berner Oberlandbahn BOB leading a long train from Interlaken, arriving here at the Wilderswil station. A similar EMU no. 311 is in the middle of the train as a second locomotive. In the background to the right old museum trains of the Schynige Platte Bahn from the beginning of the 1900s.
Photo by Ilkka Siissalo. Uploaded May 24, 1999.

In 2016 BOB's trains looked still very much the same as in the old pictures from 1999 shown above. The brown coach colours had been changed to dark blue and BOB had also bought from Stadler new fixed three coach partly low-floor coaches which make the trains even longer. But the concept remains the same. Two trains leave from Interlaken combined and they will then be split up on the way at Zweilütschinen. One half goes to Lauterbrunnen and the other half to Grindelwald.
Picture from Interlaken Ost station 1.5.2016 by Ilkka Siissalo.

A closeup picture of the same train as above, showing one half of the combination of two trains soon to be leaving Interlaken. Note that theelectric motor wagon ABeh 4/4 no.313 which is closest to the photographer on the right is exactly the same motor wagon which is also shown in the picture from 1999 shown above. The only new thing is the three coach fixed, partly low-floor unit which can here be seen furthest away from the camera.
Picture from Interlaken Ost station 1.5.2016 by Ilkka Siissalo.

BOB's motor wagon ABeh 4/4 II no.312. When compared with a picture of the similar motor wagon 313 taken in 1999 which is published above, it is clear that these have been modernised in the meantime and they have received at least new doors and new furniture inside.
Picture from Interlaken Ost station 1.5.2016 by Ilkka Siissalo.

The long combined train is leaving Interlaken. Both half-trains have at one end one of these new fixed three coach combinations which are partly low-floor. A new law in Switzerland requires that trains need to be accessible even with wheelchairs and people with disbilities. This picture shows clearly these new three coach low-floor coaches.
Picture from Interlaken Ost station 1.5.2016 by Ilkka Siissalo.

Another long combination of two trains is coming down from the mountains and is soon about to stop at the Interlaken Ost station which is the end station of BOB, Berner Oberland-Bahnen. At the front another Stadler made fixed three coach partly low-floor combination with the steering cab coach ABt 422 first.
Picture from Interlaken Ost station 1.5.2016 by Ilkka Siissalo.

The front of BOB's steering cab coach ABt 422. These new three coach fixed sets have no motors, but they very much look like Stadler's new narrow gauge electric multiple units which several Swiss narrow gauge operators have lately bought.
Picture from Interlaken Ost station 1.5.2016 by Ilkka Siissalo.

The older steering cab coaches such as this BDt 403 with a small cargo area are now just used as regular coaches in the middle of the train, behind the new three-coach Stadler units.
Picture from Interlaken Ost station 1.5.2016 by Ilkka Siissalo.

Older ABeh 4/4 motor wagons such as this no.310 are still used as locomotives just as well as the little newer ABeh 4/4 II wagons. The newer ABeh 4/4 II wagons are from the year 1986 and this one is from the year 1979. It has been thoroughly renovated in 2007.
Picture from Interlaken Ost station 1.5.2016 by Ilkka Siissalo.

Another view of the same ABeh 4/4 I motor wagon no.310 from the year 1979. It looks almost as new.
Picture from Interlaken Ost station 1.5.2016 by Ilkka Siissalo.

Motor wagon ABeh 4/4 I no.305 leading a long train uphill and stopping here at the Wilderswil station. 305 was from the 1960s, but it must be sold or scrapped by now as it is no longer mentioned in the rolling stock listings of Berner Oberland-Bahn.
Picture from Wilderswil 1.5.2016 by Ilkka Siissalo.