Material Insights · Understanding the Material World

Rail traction: Equipment and suppliers

Pantographs, transformers and 600 kW motors under the floor

What this tab covers For each method, the main pieces of equipment, who makes them (by region) and what they are made of (bill of materials).

Electric and diesel-electric trains share the same electrical drive: converter and traction motors. Electric trains add a pantograph and transformer; diesel-electrics add an engine and alternator.

Electric train and metro

Traction transformer1

Steps high line voltage (50 Hz or 16.7 Hz AC systems) down for the converter; ratings 1.5-5.2 MW.

Europe ABB (Switzerland)
Bill of materials
  • Core: grain-oriented electrical steel
  • Windings: copper or aluminium conductors, oil or ester cooling
Traction converter1

Turns line or transformer output into variable-frequency three-phase AC and back again when braking; 1.6-3 MW per unit.

Europe ABB (other makers not ranked in checked sources)
Bill of materials
  • Power semiconductors: 1.7-6.5 kV IGBT modules
  • Cooling: liquid-cooled power modules
  • Cabinets: aluminium
Traction motors and gearbox1

Turn electrical power into wheel torque; up to 600 kW per motor in high-power trains, 1.2 MW in freight locomotives.

Europe ABB (other makers not ranked in sources used)
Bill of materials
  • Stator: electrical steel laminations and copper windings
  • Rotor: copper bars (induction) or rare-earth permanent magnets
Complete electric multiple units and locomotives678

Integrate the traction chain into a train.

China CRRC Europe Alstom, Siemens Mobility, Stadler Rail Japan and Korea Hitachi Rail
Bill of materials
  • Car bodies: aluminium or stainless steel
  • Bogies and wheelsets: forged steel

Diesel-electric and battery locomotive

Diesel engine and traction alternator161012

Engine drives an alternator (traction generators up to 2.65 MW) that supplies the converter.

United States Wabtec, Progress Rail China CRRC
Bill of materials
  • Engine: large four-stroke diesel with turbochargers; Wabtec's EVO Tier 4 meets the limits through engine design without urea aftertreatment
  • Alternator: copper windings, electrical steel, rectifier
Locomotive traction battery1112

Stores braking and yard-charged energy to cut fuel use; 2.4-7 MWh per locomotive.

United States Wabtec, Progress Rail
Bill of materials
  • Cells: lithium-ion cells (chemistry and supplier not stated in sources)

Sources

  1. Traction systems for high-power applications (brochure, Rev B) (company data) ABB, 2018
  2. Worldwide Rolling Stock Manufacturers 2025 (reading sample) SCI Verkehr, 2025
  3. CRRC 2025 annual results briefing in Hong Kong CRRC Corporation, 2026
  4. Alstom's fiscal year 2025/26 results Alstom, 2026
  5. Advantage Wabtec: relentless innovation drives Evolution Series engines into the future Wabtec, 2025
  6. Wabtec: battery-electric locomotive reduces fuel use by 11% FreightWaves, 2021
  7. E-quipment highlight: 4,400 hp Wabtec FLXdrive electric locomotive Electrek, 2026