Suspension System

Air Spring And
Control Equipment

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Air Spring
Duplex Check Valve
Levelling Valve
Installation Lever

Air Spring Systems

An air suspension system is a type of suspension that operates using compressed air, generated by an electric motor–driven or engine/drive-shaft–driven air compressor. Unlike conventional suspension systems that use helical steel springs, an air suspension system employs flexible rubber bellows, commonly referred to as air springs, as the primary load-bearing element.

These bellows are typically manufactured from laminated or reinforced rubber and are filled with compressed air to support the vehicle structure. Sona Comstar supplies advanced air spring systems and control equipment for Indian Railways.

Advantages of Air Spring Systems
1. Enhanced Ride Comfort

Air suspension systems offer significantly superior ride quality compared to conventional suspension systems. By dynamically regulating air pressure within the air springs, they effectively absorb track irregularities such as shocks, vibrations, and impacts. This results in a smoother ride, improved ride index, and enhanced passenger comfort.

2. Adjustable Vehicle Height for Optimized Performance

Air suspension systems enable flexible adjustment of vehicle height based on operating conditions:

  • Lower ride height at higher speeds enhances aerodynamic efficiency and stability.
  • Increased ride height provides improved ground clearance for uneven tracks or challenging environments.

This adaptability ensures optimal performance across varying operational scenarios.

3. Automatic Load Levelling

The system automatically maintains a consistent ride height regardless of load variations. By adjusting internal air pressure, it compensates for additional weight, ensuring uniform suspension behavior. Maintains consistent floor level under varying passenger or cargo loads, enhancing system reliability and performance stability. This feature is particularly beneficial for rail coaches and other applications with frequently changing load conditions.

4. Improved Handling and Stability

Air suspension systems allow precise control of suspension stiffness characteristics, resulting in:

  • Enhanced operational stability
  • Reduced body roll during movement
  • Improved control at higher speeds

Overall, this contributes to a safer, more controlled, and predictable ride.

Air Spring – LHB Coaches

Sona Comstar manufactures advanced air spring assemblies for LHB coaches of Indian Railways, developed in collaboration with its technology transfer (ToT) partner, NITTA Chemicals, Japan.

Key Capabilities and Strengths:
  • Proven Technology Partnership: Designed and developed with global expertise through ToT collaboration with NITTA Chemicals, Japan, ensuring high performance and reliability standards.
  • High Load Capacity Design: Incorporates a belted-design air bellow, engineered to withstand super-dense crush loads, with capacity in the range of 160 kN / 140 kN for LHB, ensuring robust performance under demanding operating conditions.
  • Integrated Manufacturing Capability: Fully equipped to manufacture Emergency Springs in-house, ensuring quality control, faster turnaround, and supply reliability.
  • Comprehensive Testing & Validation Infrastructure: Established in-house facilities to conduct:
    • Routine Tests
    • Type Tests
    for complete air spring assemblies and emergency stoppers, ensuring compliance with Indian Railways standards and performance requirements.
  • Application Coverage: Utilized as a secondary suspension system in railway bogies, contributing to:
    • Increased speed potential
    • Enhanced ride comfort and stability
    • Improved overall dynamic performance

Vande Bharat Trainsets – Air Spring

Train-18, designed and developed by the Integral Coach Factory (ICF), represents India's first semi-high-speed, self-propelled trainset. It is designed to operate at speeds of up to 180 km/h, with an axle load of approximately 17 tonnes.

These modern trainsets feature advanced bolster-less bogies, engineered by ICF, and are equipped with a combination of vertical, lateral, and yaw dampers to effectively manage dynamic forces generated during high-speed operation. Working in synergy with the suspension system, these dampers play a critical role in controlling vibrations, enhancing ride comfort, and ensuring superior stability and safety.

  • • Primary Vertical Damper
  • • Secondary Vertical Damper
  • • Secondary Lateral Damper
  • • Yaw Damper
Key Functions & Benefits:
Effective Vibration Control: Minimizes vertical oscillations at the wheel–bogie interface.
Enhanced Ride Stability: Ensures smoother bogie dynamics under varying track conditions.
Improved Passenger Comfort: Reduces transmission of shocks to upper suspension levels.
Reliable & Durable Performance: Engineered for consistent functioning under demanding service conditions.
Improved Stability: Supports stable vehicle behaviour, especially on curves.
Hunting Suppression: Effectively controls sinusoidal oscillations of the bogie.
High-Speed Stability: Ensures stable performance at elevated operating speeds.
Improved Safety: Maintains wheel-track alignment under dynamic conditions.

Air Spring Control Equipment

Key Features & Components
  • Air Suspension Control: Optimizes stiffness and dampens vibrations during train movement.
  • Constant Floor Height: Automatically maintains the gap between the frame and bogie bolster, regardless of passenger load.
  • FIBA Integration: Sona Comstar equips its air springs with Failure Indication and Brake Application (FIBA) devices. In the event of an air spring rupture, FIBA immediately triggers the brakes to safely bring the train to a standstill.

Air spring and control equipment ensures a constant floor height on coaches by optimizing the values of stiffness and damping the vibration to provide passenger comfort. This equipment is used to control the secondary stage of air suspension.

Salient Features
  • • Provides more passenger comfort
  • • Optimised value of stiffness
  • • Damps the vibration during train movement
  • • Maintains gap between frame and bogie bolster
  • • Maintains constant floor height of the coaches
Applications
  • • EMU / DEMU Trains
  • • High-Speed Passenger Trains
  • • Metros
  • • LHB Coaches