Trafag AG
Trafag AG is a Swiss manufacturer of pressure, temperature, and gas density sensors headquartered in Bubikon, Switzerland, with an active product line for railway vehicles.
Trafag was founded in 1942 in Zürich by Oscar Pfrunder, initially producing transformers, before relocating to Männedorf in 1944.
The company shifted focus to measurement and control technology from the 1970s onward, ending transformer production entirely.
Ownership
It remains family-owned. Robert Pfrunder, grandson of co-founder Karl Heinrich Pfrunder, served as CEO from 1990 until 2018, having succeeded non-family leadership under Gaston Bloch after founder Oscar Pfrunder’s death in 1978. Dieter Zeisel, formerly the company’s head of research and development, has been CEO since 2018.
Trafag employs more than 350 people, with production and engineering concentrated in Switzerland and additional manufacturing sites in the Czech Republic and Germany.
The company describes itself as independent, citing this ownership structure as the basis for long-term, self-directed product planning.
Products for rail applications
Trafag supplies pressure transmitters, electronic and electromechanical pressure switches, thermostats, and temperature transmitters for rail vehicle systems.
Applications span braking systems, pantograph actuation, traction and gearbox cooling circuits, lubrication systems, air-conditioning, and door and fire-safety control circuits.
Its railway-specific transmitters and switches, such as the NAR 8258 and EPR 8283 series, are built on a thin-film-on-steel measuring principle and carry EN 50155 (railway electronics), EN 45545-2 (fire protection), and EN 61373 (shock and vibration) conformity.
The mechanical 9R5 Picostat pressure switch, introduced for rail applications, was designed specifically to meet EN 50155 requirements for rolling stock.
Market position
Trafag maintains a distribution and service network across more than 40 countries, with subsidiaries including Austria, Germany, the Czech Republic, France, the UK, Poland, India, and the US.
Its railway customer base consists of manufacturers of rolling stock units and systems rather than train operators directly.
Beyond rail, Trafag’s sensors also serve shipbuilding, hydraulic systems, large engines, hazardous-area (Ex) environments, and high- and medium-voltage switchgear through its gas density monitoring line.
The company operates an ISO 17025-accredited calibration laboratory in Switzerland, supporting both production quality and third-party calibration services.
