50 Hz working group - 50-Hz-Arbeitsgemeinschaft
The 50 Hz working group or 50 Hz group , English 50 c / s Group , French Groupement d'Étude d'Électrification Monophasé 50 Hz , later Groupement 50 Hz , was a consortium of European rail vehicle manufacturers , which electrical systems and traction vehicles for manufactured and sold the 25 kV 50 Hz traction power system. The company's registered office was in Zurich . 
The Association was founded in 1954  on the initiative of the French railway engineer Fernand Nouvion founded with the aim of the export market for the in France developed technology of railway electrification with a voltage of 25 kV and a frequency to market of 50 Hz. The consortium achieved its first success with the electrification of the Istanbul S-Bahn . This was followed by the Portuguese Railways and export successes to the Soviet Union and China . A particularly large order was the electrification of the Indian railwayswith 25 kV and 50 Hz. The consortium sold equipment parts for over 1000 locomotives to India  and was very successful until the mid-1980s.
The following manufacturers belonged to the working group when it was founded:
- Electrical Construction Workshops of Charleroi (ACEC) aus Belgien
- AEG from Germany
- Alsthom from France
- Brown, Boveri & Cie. (BBC) from Switzerland
- Jeumont from France
- Maschinenfabrik Oerlikon from Switzerland
- Electric traction equipment (MTE) from France
- Schneider-Westinghouse from France
- Siemens from Germany
Some of the companies listed above later merged with each other. In the 1990s ACEC, AEG, Alsthom, BBC and Siemens were still in the group. BBC left the 50 Hz community after merging with Asea. 
scope of delivery
Most of the projects included both fixed systems and traction vehicles and were carried out by the consortium as general contractor . By 1975, over 2150 locomotives , multiple units and electrical equipment for multiple units had been delivered. In addition, 600 km of railway lines were electrified and substations with a total output of 330 MVA were delivered. The scope of delivery also included signal and radio systems as well as remote control devices.  The projects were carried out in the following countries:
- Yugoslavia 
- South Korea
- People's Republic of China
- If 
- Hungary 
- Turkey 
- Soviet Union 
- Costa Rica 
- Belgian Congo (now the Democratic Republic of the Congo ) 
The 50 Hz consortium built the following vehicles:
|Land||Railway company||designation||number||Construction year||image|
|People's Republic of China||CNR||6Y2||25||1958–1961|
|People's Republic of China||CR||8K||150||1987|
|South Africa||Railway network||14E||3||1991–1994|
- 50 Hz working group. Collection of over 70 advertising leaflets and brochures. Partly with color images. In: lot-tissimo.com. Retrieved April 10, 2016 .
- Amandus Jäger: 50 c / s Group (Groupement 50 Hz - 50 Hz working group). Retrieved April 11, 2016 .
- Amandus Jäger: Business. In: ajaeger.ch. Retrieved April 10, 2016 .
- Inserat 50 c/s group locomotives. In: eBay. 1975, abgerufen am 10. April 2016.
- Costa Rica - Friends of Latin American Railways. In: www.ferrolatino.ch. Retrieved April 12, 2016 .
- NRZ Electric locomotive EL1 class on test in Zimbabwe. - a photo on Flickriver. In: flickriver.com. Abgerufen am 12. April 2016.