The Railway Industry – Our solutions

Significant temperature variations, shocks, vibrations, electromagnetic interference, and more: electrical components for the rail industry must operate safely and reliably even in extreme conditions.

celduc® relais has developed its SSRs with the highest quality standards.

We have been a reliable and experienced partner in the rail industry for many years.

You can rely on our solutions!

In this market segment, our Solid State Relays are used for:

– HVAC (Heating Ventilation Air Conditioning)

High voltage floor heating

Compressors for hydraulic or pneumatic braking

Wheel greasing compressor

– Switch point heating

– Railway signalling


Air Conditioning/HVAC system
Floor Heating
Window/Windscreen Heating


Passenger comfort has become an essential sales asset.

Travelling in an air-conditioned, temperature-controlled and filtered atmosphere is a basic right for today’s rail passengers. This applies to both new and refurbished trains. Passengers will notice even the slightest shortcoming in terms of these creature comforts. In rail transport systems, invitations to tender only requiring heating and ventilation functions are now extremely rare.

Air conditioning systems require skills and expertise in a variety of subjects: thermodynamics, aeraulics, acoustics, electricity, mechanics, automatic controllers, etc.

SSRs are used for heating/cooling regulation in passenger & driver compartments in order to precisely control temperatures in the train.

Our key products:

SU/SUL with an ESUC Current Monitoring Module: The ESUC module is an option available for the celpac® 2G range and can be connected directly to the SU/SUL Solid State Contactor. This module continuously measures the load current. It is possible to monitor 5 heaters simultaneously. Current range: 2-40A/Control: 8-32VDC

High Voltage Single Phase Solid State Relays: SO885960 and SO889060

High Voltage Floor Heating

Our key product: 50A-750Vdc fully protected HV DC SSR for controlling HV floor heaters supplied directly by the catenary

Our IGBT based SDI SSR can switch 50A @ 750Vdc nominal in a fast, reliable and safe way. In every situation, operational safety is ensured:

  • Built-in, over-voltage protection for inductive DC supply lines (max. L/R = 20ms), OV4
  • Built-in load short circuit protection: by detecting IGBT saturation, short circuits on the load will block the unit, thereby maintaining safety
  • Built-in, overload temperature protection: should overheating occur, the unit will automatically switch off
  • Status feedback for safety
  • HL2 (Hazard Level EN 45545-2)

The SDI SSR is specifically designed for the most demanding DC power switching applications. This is the unit that the railway companies, either rolling stock or infrastructure, have been waiting for, for years!

Compressors for Hydraulic or Pneumatic Braking

Hydraulic and pneumatic braking systems contain pumps and compressors.

Our SSRs are used for controlling these compressors.

Our okpac® range is one of the solutions we offer, but this depends on your specific system design requirements. Electrical specifications can vary from manufacturer to manufacturer. You can rely on our expertise!

Key products: okpac® range

  • This range is designed for all types of loads from 12 to 125A
  • Output voltage from 24 to 690VAC (600V – 1200V – 1600V peak)
  • 4th generation TMS² dependable technology

Tramway Wheel Greasing Compressor

This system is designed to lubricate tram wheel flanges. The system works by applying

a lubricant mixture to the contact area of the tram wheel flanges using compressed air.

Key products: DC Solid State Relays for motor control

We offer a complete range of DC solid state relays up to 1700Vdc, 0 to 150A for DC applications.

Our DC SSRs are used to control wheel greasing compressors.

Railway Switch-Point Heating

In areas where temperatures are regularly below freezing, railroad rail switch mechanisms can often malfunction. This, combined with an accumulation of snow and ice, can lead to railroad switch mechanism failures.

The solution? Railroad switch heaters.

Our SSRs are used to control these electric switch heaters. For automatic operations, the system can be equipped with Rail Snow Detectors and temperature sensors.

Our key products:

To ensure that the system operates efficiently, choosing reliable components is important.

celduc’s SO range is used in this system.

Railway Switch-Point Motors

Motor control has always been a complex process. This is because a motor is, first and foremost, an inductive type of load, with high starting currents and over voltages generated at turn-off.

This is why Solid State solutions are becoming more widely used to control motor loads.

celduc’s Solid-State-Relays offer the best possible features to meet all of the above-mentioned needs.

Our solution: 5 x high voltage AC SSRs for motor reversing

Signalling & Train Accessories

Our key products: PCB relays

At celduc® relais we offer a wide range of Interface Solid State Relays

-Our SKA range (AC output) up to 6A 230 or 400VAC, with built-in voltage protection

-Our SKD range (DC output – Bipolar technology) up to 3A 60VDC or 200VDC and SKLD range (DC output – MOSFET technology) up to 12A 36VDC or 60VDC

Both ranges include other products, including a ceramic substrate (DCB technology: Direct Copper Bonding):

-Our SKL range can be mounted on a heatsink, ranging from 16A to 75A.

-Our SKH range with integrated heatsinks has an output current with ventilation up to 25A.

To download our catalogue for railway industry solutions – click here