How to Correctly Calibrate Hi-Rail Wheels: Common Errors Explained

Correctly calibrating hi-rail wheels is crucial for safe and efficient operation. Improper calibration can lead to wheel slippage, excessive wear, and even derailment risks. Let’s break down the calibration process and the common errors to avoid.

Understanding Hi-Rail Wheel Calibration

Hi-rail wheels are the retractable rail wheels on a hi-rail vehicle that enable it to operate on railway tracks. Calibration ensures:

• Proper wheel gauge alignment (distance between rail wheels).
• Correct weight distribution between the road tires and rail wheels.
• Adequate contact pressure to maintain traction and stability on the rails.

Step-by-Step Calibration Process

Positioning the Vehicle on Level Ground

Before calibration, always position the vehicle on a level surface. Uneven ground can cause inaccurate gauge measurements, leading to misalignment on the tracks.

Inspecting the Hi-Rail System

A thorough inspection should be performed, including:

• Checking for hydraulic leaks in the rail gear.
• Ensuring all bolts and fasteners are secure.
• Verifying the wear condition of the hi-rail wheels.

Adjusting Wheel Gauge Alignment

The distance between the hi-rail wheels must match the track gauge. Standard track gauge in North America is 56.5 inches (1,435 mm). If the wheels are set too wide or too narrow:

• Too wide: Risk of derailment.
• Too narrow: Excessive wear on wheel flanges and track damage.

Setting the Proper Load Distribution

Hi-rail vehicles must have a balanced weight distribution between the rubber tires and rail wheels.

• Too much weight on the rubber tires reduces rail traction.
• Too much weight on the hi-rail wheels increases friction and wear.

Verifying Rail Contact Pressure

Rail wheels must exert adequate downward pressure for proper traction. The wheels may slip on the rail if the contact pressure is too low, reducing braking efficiency and control.

Common Calibration Errors and How to Avoid Them

Incorrect Wheel Gauge Adjustment

Error: Wheels set too wide or too narrow.
Solution: Use precision measuring tools and follow manufacturer specifications to ensure proper gauge settings.

Uneven Load Distribution

Error: Excessive load on either the hi-rail wheels or the road tires.
Solution: Adjust hydraulic pressure and suspension settings to achieve even weight distribution.

Worn or Damaged Rail Wheels

Error: Using hi-rail wheels with excessive wear.
Solution: Regularly inspect and replace worn wheels to maintain optimal rail contact and prevent derailment.

Failing to Re-Torque Bolts After Calibration

Error: Loose bolts can cause misalignment over time.
Solution: Always re-torque all bolts after calibration and perform periodic inspections.

Skipping Load Testing

Error: Failing to test the hi-rail system under operational conditions.
Solution: Conduct a dynamic test on a controlled section of the track to verify stability, traction, and braking performance.

Final Safety Checks

After calibration, conduct a comprehensive safety check, including:

• Verifying proper wheel engagement and disengagement
• Checking braking efficiency on rails
• Ensuring no hydraulic leaks or abnormal noises

Recap 

Proper hi-rail wheel calibration is critical for safety, efficiency, and equipment longevity. You ensure smooth, stable, and safe operation by avoiding common errors like misaligned gauge settings, improper load distribution, and insufficient contact pressure. Regular inspections and adherence to manufacturer guidelines will keep your fleet running efficiently.

If you need professional hi-rail calibration services in Chicago Heights, IL, contact Fleet Tech Inc today.