You have successfully submitted your enquiry. Someone from our company will respond ASAP

Secure DC/DC converters in Train and Track Side

Email Address
Bäckgatan 10,
597 25,

Polyamp has continuously supplied switch mode DC/DC converters to the international railway industry since 1973. The company now has the capability to meet performance requirements of worldwide applications and to accommodate the extreme environmental demands of hot and humid Bangkok, hot and dry Australia, and the arctic north of Sweden.

System applications

All Polyamp DC/DC Converters for railway applications are designed to be safe, technically compliant, reliable and cost effective. Applications include systems for surface and underground trains powered by both electric and diesel locomotives, trams and special vehicles used by the operators and maintainers. Systems can be categorised as:

Train systems

Systems used by the driver are specifically safety conscious and a fault will either stop the train or automatically revert it to an alternative fail safe mode.

  • Driver computer
  • Train control
  • Remote control
  • Emergency starting
  • Radio
  • Head and backlight (Xenon / Halogen / LED)
  • Alarm (bells / horns)
  • Wipe washers
  • Cameras

Passenger comfort systems

  • Displays and information
  • Lamps (halogen / LED)
  • IT-equipments
  • Sound / communication
  • Toilets
  • Coffee and restaurant railway operating systems
  • Counting devices, ticketing
  • Remote control
  • Cameras
  • Doors
  • Lifts including disabled facilities
  • Track control system GSM-R

Technical standards

Modern trains achieve savings of weight and space by using battery voltage up to 110Vdc but most system equipments require input power at 12V and 24Vdc. The DC/DC Converter transforms the basic 110Vdc to 12Vdc and 24Vdc, but can also perform the inverse if necessary, such as convert 12Vdc and 24Vdc to 110Vdc. Polyamp handles DC voltages from 12 to 500Vdc. Special models for tram voltages +1000 V are available.

Train standards

Polyamp DC/DC converters are designed to meet the railway specific standards for electronic equipment onboard trains including those specified in EN50155 and IEC60571. They are mechanically rugged for reliable operation in a very harsh environment throughout their whole life.

Where these standards specify different levels for particular conditions, applicable ratings will be confirmed and agreed for individual customer applications.

An additional benefit of the Polyamp DC/DC Converters is that when they are used as a power source for equipments, that in themselves are not compliant with the EN 50155 and IEC 60571 standards, they effectively function as a filter and galvanic separation to shield those equipments. This allows the railway operator to use commercial on the shelf (COTS) equipments for such applications.

Environmental specification

Ambient temperature
The standard level is -25°C to +55°C but most applications specify -25°C to +70°C (T3).
Polyamp DC/DC Converters can be supplied to operate in temperatures from -40°C to +85°C.


Our DC/DC converters are compliant with the EN 50121-3-2 (IEC 62236-3-2) and also EN 50121-4 (IEC 62236-4) EMC performance specified for electronic equipments.

Our emission levels are much lower (-30dB) than the train limits. Our outputs also meet the immunity demands, which few competitors do. It means our output can be distributed and feed electronic equipment that does not meet the EN 50155 input variations.

Fire and smoke

Most models meet the fire and smoke standard EN45545-2 with some simple installation criterias.

Shock and vibration

Compliant with the IEC/EN 61373 requirements for body mounted class B. Polyamp DC/DC converters are regularly used in military vehicles and fork lifts, which have more severe vibration requirements.

Input voltage range of DC/DC converters

EN 50155 and IEC 60571 specify a nominal input variation of ±30%, including ripple but some other specifications define ±40%. For modern trains with better d.c. supply systems they can be relaxed and for markets still using RIA12 specifications, Polyamp can also supply models that meet its surge requirement of 3.5x nominal input voltage. Input voltages ranges for vehicles and railway applications.

White Papers


  • MRTA Pink Line, Bangkok

    The MRT Pink line was opened to the public in December 2023 to meet the travel demands of northern Bangkok.

Polyamp Åtvidaberg
Bäckgatan 10
597 25

Email address
Polyamp Sollentuna
Tingsvägen 19
191 61