Case study

Norwegian State Railways (NSB), Oslo

Seventy-five new trains run by The Norwegian State Railways (NSB) for traffic in the Oslo area and southern part of Norway have been equipped with Univox TLS-2


NSB has purchased 75 five-part electrical trains of the FLIRT family from Swiss train manufacturer Stadler Rail. Passenger Information System (PIS) supplier has been the Finnish company Mitron. Some of the trains are used as Long Local version for the S-Bahn traffic in the Oslo area, with travelling times of up to 90 minutes. Others are used as Short Regional, and will traffic the area of Southern Norway for connections with travelling times of up to 3 hours. These different traffic conditions and the high ambition of user friendliness for disabled travellers along with the harsh Norwegian climate, posed a real challenge.


The ambition was also to reduce the time and costs for installation of the systems. As always when installing loop systems on-board rolling stock, there are a number of technical challenges: Attenuation of the magnetic field due to the metal in the cars (in this case the train cars were made of aluminium), magnetic background noise from braking systems and electrical cables, available electrical power, interface to the on-board Passenger Information System, vibrations, temperature variations, dust, cramped installation space... All these challenges had to be overcome by choosing the right mix of power, loop design, loop wire placement and of course – the right loop driver for the job!


The train cars are characterised by an advanced thermal and acoustic insulation and fulfil the high requirements needed for winter operation in Norway. This fact made it easier to succeed, but nevertheless the demands on a hearing loop amplifier installed on board rolling stock is higher than for most other professional settings.

After thorough testing in a real environment and with careful design of the loop itself (placement in the ceiling), a pre-set pattern of all input and output levels was established. This, together with the compact physical measures of the driver itself, made the installation of the loop drivers in the train cars relatively easy. No additional measurement or adjustment was needed on-sight!

Products used:

  • 30 Univox® TLS-1 Transportation Loop System
  • 345 Univox® TLS-2 Transportation Loop System

Responsible companies:

  • Loop design and technical planning: Univox, Sweden
  • Passenger Information System design: Mitron Oy, Finland
  • Loop system installation and integration with PIS: Mitron Oy, Finland
  • Train supplier: Stadler Rail, Switzerland

Following a close collaboration with both train manufacturer and PIS supplier, 375 train cars have been equipped with hearing loops completely covering each train car. The supply of pre-set loop drivers made the installation both faster and easier, completely eliminating the risk of non-conformant loop systems. The rugged design of the driver, including dust coated PCB, glued capacitors and dip switch settings of all levels, will ensure many years of problem-free service for the hearing impaired.

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