High-Speed Rail Infrastructure

Advanced 2x25kV AC Traction Power Supply Systems

Powering heavy-haul and high-speed railway networks efficiently using auto-transformer (AT) technology over long distances with reduced electromagnetic interference.

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System Quick Status

  • Feeding Voltage: 50 kV System (2 x 25 kV)
  • Phase Angle: Out of phase (+25kV / -25kV)
  • Transmission: Reduced line losses & drop
  • Application: Heavy Haul & Bullet Trains

Why 2x25kV AT System?

Designed for modern heavy traffic railways demanding higher power transfer capabilities.

Higher Power Capacity

Delivers double the voltage to the pantograph section (50kV transmission) while supplying standard 25kV to rolling stock via Auto-Transformers.

Reduced Voltage Drop

Allows greater distance between Sub-Stations (TSS) due to lower current circulation and efficient power compensation.

Minimal Interference

Significantly reduces electromagnetic interference (EMI) on nearby telecommunication lines and signaling equipment.

Core Architecture & Working Principle

The 2x25kV system utilizes a feeder wire, overhead contact line (catenary), and a rail return system connected through Auto-Transformer (AT) sites spaced strategically along the track alignment.

  • Contact Wire (+25kV): Feeds power directly to the electric locomotive pantograph.
  • Feeder Wire (-25kV): Carries out-of-phase current to balance loads over distance.
  • Auto-Transformers (AT): Step down the 50kV transmission back to 25kV supplies for locomotives.
Railway Track Infrastructure Typical Electrified Heavy-Haul Track Corridor

Technical Specifications

Standard parameters applied in modern high-speed rail electrification projects.

Parameter Nominal Value Design Function
System Voltage 50 kV (Between Feeder & OCL) Long distance power transmission
Pantograph Voltage 25 kV (Between OCL & Rail) Locomotive traction supply
Auto-Transformer Spacing 10 km to 15 km intervals Voltage stabilization & balancing
Traction Substation (TSS) Spacing 40 km to 60 km Bulk power intake from grid utilities

Project Consultation & Inquiries

Get in touch with our railway power infrastructure engineering team.