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voestalpine Railway Systems Nortrak

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Frogs - Moveable Point Frogs (MPF)

Engineered for Reliability, Performance, and Long Service Life

vaRS Nortrak's Moveable Point Frog (MPF) systems are engineered for demanding freight and passenger rail applications where long service life, reduced maintenance requirements, and operational reliability are critical.

By providing a continuous running surface through the frog, MPFs reduce wheel impact, vibration, and wear while supporting smoother vehicle transitions through the turnout. The result is improved ride quality, lower maintenance requirements, reduced noise, and extended component service life.

Why Choose vaRS Nortrak MPFs?

Continuous Running Surface: The movable point eliminates the wheel gap found in conventional fixed frogs, reducing impact loading, vibration, wear, and noise while supporting smoother wheel transitions through the turnout.

Lower Maintenance Requirements: Reduced impact forces help minimize wear on critical turnout components, reducing maintenance demands and extending service life.

Improved Ride Quality: The continuous wheel path through the frog provides a smoother transition through the turnout, reducing vibration and supporting passenger comfort.

Proven for High-Traffic Applications: MPFs are ideal for heavy-haul freight, passenger rail, commuter rail, and other high-density rail corridors where reliability and long-term performance are essential.

Buy America Compliant: Designed, tested, manufactured, and assembled in the United States to meet Buy America requirements while supporting the needs of freight and passenger rail operators across North America.

MPF

Key Benefits

  • Reduced maintenance requirements
  • Lower lifecycle costs
  • Reduced wheel impact and vibration
  • Smoother train transitions
  • Extended component service life
  • Improved ride quality
  • Proven in high-traffic applications
  • Designed for North American operating conditions
  • Buy America compliant

Every aspect of the MPF design is engineered to manage the forces generated as wheels transition through the frog. By reducing impact loads and stress concentrations, we're able to improve reliability, extend component life, and lower maintenance requirements.

Eric Gray - Engineering Manager, R&D and Projects

Design Features That Make the Difference

ThickWeb (136TW) Point Design: The ThickWeb movable point design increases stiffness and torsional rigidity, improving point seating, reducing unwanted movement, and supporting long-term operational reliability.

Optimized False Flange Cut Design: The smooth-radius false flange cut reduces abrupt transitions and localized stress concentrations, helping reduce fatigue-related failures and improve component longevity.  

Huck-Bolted and Hot-Riveted Connections: Huck-bolted and hot-riveted connections are designed to resist vibration while maintaining clamping force and structural integrity under demanding operating conditions.

Enhanced Load Distribution: The MPF design helps distribute forces more effectively through the frog transition zone, reducing stress concentrations and improving performance in high-tonnage and higher-speed service.

MPF Accessories

Solutions Designed Specifically for MPF Installations

vaRS Nortrak offers accessories engineered to address common maintenance and operational challenges associated with Moveable Point Frog turnouts. Suitable for retrofit installation on both existing and new MPF systems, these solutions help railroads improve maintainability, reliability, and long-term performance.

  • Rod Support

    Reduce Switch Machine Loading

    The Rod Support is designed specifically for Moveable Point Frog applications to reduce the static and dynamic forces transmitted from switch rods to the switch machine. Suitable for retrofit installation on existing MPF systems, it supports both the point detector rod and lock rod, helping reduce switch machine loading and wear on critical components.

    Key Benefits

    • Reduces static and dynamic loading on the switch machine
    • Supports both point detector rods and lock rods
    • Independently adjustable supports
    • Adjustable in 1/16-inch increments
    • Electrically insulated for signal reliability
    • Straightforward retrofit installation
    • Easy to inspect and maintain
    • Buy America compliant
    • Designed, tested, and manufactured in the USA

  • Reduce Friction and Lubrication Requirements

    The MPF Slide is designed to reduce friction acting on moveable point frogs, helping minimize maintenance requirements and reduce the need for lubrication.

    Its bottom-up design gently lifts the point during movement, promoting smoother operation and reducing friction between contact surfaces. The system can be retrofitted to existing Moveable Point Frog installations and requires no custom tie plates.

    Key Benefits

    • Reduces friction on moveable point frogs
    • Helps minimize maintenance and lubrication requirements
    • Straightforward retrofit installation
    • Standard 1/16-inch vertical point lift
    • Adjustable in 1/32-inch increments
    • Laterally adjustable for optimized point lift
    • No custom tie plates required
    • Buy America compliant
    • Designed, tested, and manufactured in the USA

Frequently Asked Questions

  • MPFs provide a continuous running surface through the frog that helps reduce impact loading, vibration, wear, and maintenance requirements while supporting smoother train operation.

  • By providing a continuous running surface through the frog, MPFs reduce wheel impact, vibration, and wear. This helps minimize damage to critical turnout components, reducing maintenance requirements and extending service life.

  • MPFs are commonly used in heavy-haul freight, passenger rail, commuter rail, and high-density mainline operations where reliability and long service life are priorities.

  • Key design features include ThickWeb movable point rails, optimized false flange cut geometry, and Huck-bolted and hot-riveted connections engineered to improve durability and long-term performance.

  • Yes. The Rod Support and MPF Slide are designed as retrofit solutions and can be installed on existing Moveable Point Frog systems, helping railroads address loading, friction, and maintenance challenges without replacing the turnout.