RBS Gem 4/4 121 - RBS Gem 4/4 121

Fe 4/4
The SZB Gem 4/4 121 on June 5, 1984 in Biberist.
The SZB Gem 4/4 121 on June 5, 1984 in Biberist.
Numbering: 11–12
Number: 2
Manufacturer: SIG / MFO
Year of construction (s): 1912
Ausmusterung: 1961 and 2016
Axis formula : Bo'Bo '
Gauge : 1000 mm (Meterspur)
Length over buffers: 11,53 m
Trunnion Distance: 6,21 m
Bogie axle base: 1,5 m
Service mass: 24,1 t
Top speed: 45 km / h 1912: 30 km / h
Hourly output : 180PS Diesel:154PS
Power system : 1250V DC 1912:750V DC
Number of traction motors: 4

The Gem 4/4 121 is a freight railcar of the Regionalverkehr Bern Solothurn (RBS). With a service life of 104 years, it is one of the longest-used rail vehicles in Switzerland. Essential construction and components of the vehicle are original.


The vehicle was purchased in 1912 by the Bern-Zollikofen train (BZB) as freight railcars Fe 4/4 12 together with an identical sister vehicle Fe 4/4 11. After the merger of Bern-Zollikofen train with the electric Schmalspurbahn Solothurn-Bern to Solothurn-Zollikofen-Bern Bahn In 1922 the vehicles were given the numbers 31 and 32. After installing a Deutz diesel generator in 1960, the vehicle was first designated as Ge 4/4 32 and in 1973 renumbered as Gem 4/4 121. The Fe 4/4 31, however, was broken off in 1961. In 2002 the vehicle was prepared for spraying the contact line with antifreeze, which (temporarily) prevented electrical operation. However, it was not redrawn to Gm 4/4 121.


The vehicles were procured in light gray paintwork together with other passenger railcars and trailer cars for the opening of the BZB. They were ordered from the Schweizerische Industriegesellschaft Neuhausen am Rheinfall (SIG). The electrical equipment, like the stationary electrical systems (converters, catenary), came from the Oerlikon machine factory . [1] Only a few modifications were made until 1960. As with numerous other vehicles, the lyre bar was replaced by a pantograph in 1929. In 1940 the wooden car body was clad with sheet metal and in 1959 the electrical system was adapted to the new mains voltage of 1250 volts.

First narrow-gauge two-motor vehicle

With the installation of the diesel generator in 1960, SZB received its first dual-power locomotive . Previously, the SZB only had the small diesel-powered construction tractor Tm 2/2 401 for operations without electricity from the overhead line. [2] This enabled the vehicle's range of tasks to be significantly expanded. In addition to freight transport, the vehicle has also been used intensively in construction services since then.

Mission biography

Freight traffic was a central motive for the construction of the BZB. The task of the two railcars was to run freight trains between Zollikofen station and the numerous industrial companies along the route. These freight trains consisted of standard-gauge freight cars that were jacked up on narrow-gauge roller bolsters. Goods were also transported from Zollikofen to the Worblentalbahn via a connecting curve in Worblaufen . After the diesel generator was installed, the vehicle was also rented out to other railways several times. The Gem 4/4 121 was used by GFM in 1975 and 1976, and in 1979 the vehicle was loaned to MOB . [3] From 2002 the vehicle was only used sporadically and withdrawn in 2016.



  • Jürg Aeschlimann: Bern-Zollikofen-Bahn. 100 years of history. Systems and rolling stock of the RBS route Bern-Zollikofen (lines S8, S9), Krattigen 2012, ISBN 978-3-907579-55-8 .
  • Jürg Aeschlimann: Regional traffic Bern-Solothurn. Volume 2: Solothurn-Zollikofen-Bern. Krattigen 2016, ISBN 978-3-907579-29-9 .
  • Theo Stolz, Paul Bucher: Solothurn-Zollikofen-Bern Railway. History and rolling stock. Worblaufen 1979.


Individual evidence

  1. Jürg Aeschlimann: Bern-Zollikofen-Bahn, 100 years of history, facilities and rolling stock of the RBS line Bern-Zollikofen (lines S8, S9), Krattigen 2012, p. 13.
  2. ^ Theo Stolz, Paul Bucher, Solothurn-Zollikofen-Bern Bahn, history and rolling stock, Worblaufen 1979, p. 111.
  3. Jürg Aeschlimann, Regionalverkehr Bern-Solothurn, Volume 2: Solothurn-Zollikofen-Bern, Krattigen 2016, p. 195.