RVO or Regionalverkehr Oberaargau is the marketing name used by buses and trains in the regions of Solothurn and Oberaargau in a small part of the Kantons Aargau and Solothurn, central Swiss flatland. In practise the trains are owned by a group of two small companies, belonging to the OSST Gruppe or Oberaargau-Solothurn-Seeland-Transport.

The "real" RVO line (ex. OJB) is a stretch of 16 km of 1 metre gauge width narrow gauge railroad, electrified with 1200V DC. It was opened for traffic in 1907. The other piece of the service is SNB or Solothurn-Niederbipp-Bahn, also only 14 km long and also 1 metre gauge width, 1200V DC traffic, leading "from nowhere to nowhere, in the middle of nowhere": connecting the extremely small countryside village of Niederbipp to the station of Langenthal by the main SBB train line. The SNB line was opened for traffic in 1918 and it can be considered almost a miracle that it is still in operation.

The Solothurn-Niederbipp-Bahn SNB is one of the smallest of the over 30 private railroads in Switzerland. The company operates a short track in the Kantons of Solothurn and Aargau, feeding traffic from small villages to the main railroad lines in Langenthal and Niederbipp. Track is narrow gauge, 100 cm, and has been opened in 1918. The company has four electric motor units of type Be 4/4, built 1966-78, each weighing 35 tons, being 18,10 m long and having a maximum speed of 65 km/h. Number 302 shown here went through a modernisation in 1998-99. The company SNB now belongs to a bigger group, RVO or Regionalverkehr Oberaargau (OSST group). During the modernisation the trainīs red and white colouring scheme was changed to the present orange-white of RVO. Picture taken at Langenthal station in July 1999 by Ilkka Siissalo, ilkka.siissalo(at-sign)iki.fi
Uploaded 18 June 2002

The Solothurn-Niederbipp-Bahn SNBīs four electric motor units operate usually each with one steering wagon, here no. 151 attached to EMU Be 4/4 no. 302. Note the Swiss habit for end of train signal: just one white light is on. Picture taken at Niederbipp village in July 1999 by Ilkka Siissalo, ilkka.siissalo(at-sign)iki.fi
Uploaded 18 June 2002

The Solothurn-Niederbipp-Bahn SNBīs Be 4/4 no. 302 stopping to take a passenger at Niederbipp village in July 1999. Note the missing of any kind of a station, just a ticket automate is placed in a small shelter by the railroad crossing. Photo by Ilkka Siissalo, ilkka.siissalo(at-sign)iki.fi
Uploaded 18 June 2002

Another view of the Solothurn-Niederbipp-Bahn SNBīs Be 4/4 no. 302 at Niederbipp village in July 1999 by Ilkka Siissalo, ilkka.siissalo(at-sign)iki.fi
Uploaded 18 June 2002

The Solothurn-Niederbipp-Bahn SNBīs Be 4/4 with one coach at Langenthal station. Photo in July 1999 in Langenthal by Ilkka Siissalo, ilkka.siissalo(at-sign)iki.fi
Uploaded 18 June 2002

This oldtimer, Ge 4/4 no. 56 from 1917 was one of the famous "Bernina-Krokodil" engines designed for the narrow gauge Rhätische Bahn network in the beginning of the nineteen hundreds. It used to belong to the LMB company and used to drag passenger wagons in Aargau in the twenties and it is the only one of its kind in central Switzerland. In 1972 it was unfortunately spoiled by adding oversized modern buffers and a modern painting which doesnīt fit the oldtimersīelegance and it got the present day number of 126 of RVB. Since then it has been in occasional use for spreading gravel. It weighs 20 tons and achieves a modest maximum velocity of 35 km/h. Photo at Langenthal station in July 1999 by Ilkka Siissalo, ilkka.siissalo(at-sign)iki.fi
Uploaded 18 June 2002

This diesel / electric De 4/4 no. 121 of the RVO is another unique example - only one of its kind. It and the oldtimer Ge 4/4 from 1917 are the only engines designated as locomotives at the narrow gauge RVO/SNB "network" of about 30 km track. It is built in 1987, deliberately fitted with huge oversize buffers and equipped for all kinds of railroad track and aerial cable maintenance work. It is 14,4 meters long, weighs 49 tons and has a maximum speed of 65 km/h. It can operate both with electricity or on diesel power. Photo at Langenthal in July 1999 by Ilkka Siissalo, ilkka.siissalo(at-sign)iki.fi
Uploaded 18 June 2002