Guard faces are the working surfaces of guard rails that contact wheel flanges to prevent derailment and guide wheelsets through critical track sections.
Basic Specifications
| Parameter | Standard | Heavy Duty | High-Speed |
|---|---|---|---|
| Face Angle | 1:40 | 1:35 | 1:45 |
| Height | 38mm | 42mm | 40mm |
| Surface Finish | Ra 3.2 | Ra 2.8 | Ra 2.4 |
| Hardness | 320-350 HB | 350-380 HB | 340-360 HB |
| Contact Zone | 25-35mm | 30-40mm | 28-38mm |
Critical Dimensions
| Measurement | Value | Tolerance | Notes |
|---|---|---|---|
| Face Height | 38mm | +2/-0mm | Above running rail |
| Working Face | 30mm | ±2mm | Contact area |
| Top Radius | 13mm | ±1mm | Upper corner |
| Bottom Radius | 8mm | ±1mm | Lower corner |
| Surface Angle | 1:40 | ±1:80 | Standard cant |
Material Properties
| Property | Standard | Premium | Ultra |
|---|---|---|---|
| Hardness | 320-350 HB | 350-380 HB | 380-420 HB |
| Tensile Strength | 900 N/mm² | 1200 N/mm² | 1350 N/mm² |
| Yield Strength | 500 N/mm² | 800 N/mm² | 900 N/mm² |
| Impact Value | 20J | 25J | 30J |
| Wear Rate | 1.0mm/yr | 0.7mm/yr | 0.4mm/yr |
Wear Limits
| Parameter | New | Warning | Condemning |
|---|---|---|---|
| Face Wear | 0mm | 8mm | 12mm |
| Profile Deviation | 0mm | 2mm | 4mm |
| Surface Roughness | Ra 3.2 | Ra 6.4 | Ra 12.8 |
| Angle Change | 1:40 | 1:35 | 1:30 |
| Height Loss | 0mm | 5mm | 8mm |
Surface Treatment
| Process | Specification | Purpose |
|---|---|---|
| Grinding | Ra 3.2 | Surface finish |
| Shot Peening | 0.4mmA | Stress relief |
| Edge Treatment | R5mm | Corner protection |
| Lubrication | Dry film | Wear reduction |
| Hardening | Flame/Induction | Surface hardness |
Installation Requirements
| Parameter | Value | Tolerance |
|---|---|---|
| Alignment | 0mm | ±1mm |
| Level | 0mm | ±1mm |
| Face Angle | 1:40 | ±1:80 |
| Gauge | 1393mm | ±2mm |
| Fastener Torque | 250 Nm | ±20 Nm |
Regional Standards
UIC (Europe)
| Parameter | Value | Tolerance |
|---|---|---|
| Face Height | 38mm | +2/-0mm |
| Face Angle | 1:40 | ±1:80 |
| Check Gauge | 1393mm | ±2mm |
| Surface Finish | Ra 3.2 | ±0.8 |
AREMA (North America)
| Parameter | Value | Tolerance |
|---|---|---|
| Face Height | 1-1/2″ | +1/16″/-0″ |
| Face Angle | 1:40 | ±1:80 |
| Check Gauge | 54-5/8″ | ±1/8″ |
| Surface Finish | 125μin | ±25μin |
Maintenance Requirements
| Task | Frequency | Method |
|---|---|---|
| Visual Check | Weekly | Direct observation |
| Wear Measurement | Monthly | Digital gauge |
| Profile Check | Quarterly | Template gauge |
| Surface Finish | Semi-annual | Roughness meter |
| NDT Inspection | Annual | Ultrasonic |
Common Defects
| Defect | Cause | Action |
|---|---|---|
| Spalling | Impact | Replace section |
| Wear Pattern | Normal use | Monitor/Replace |
| Cracking | Fatigue | NDT/Replace |
| Plastic Flow | Overload | Grind/Replace |
| Corrosion | Environment | Clean/Treat |
Quality Control
| Test | Method | Frequency |
|---|---|---|
| Hardness | Portable tester | Each piece |
| Profile | Laser scan | 100% |
| Surface | Roughness meter | Sample |
| Alignment | Optical | Each piece |
| Ultrasonics | Pulse-echo | Critical areas |
Performance Monitoring
| Parameter | Method | Limit |
|---|---|---|
| Wear Rate | Digital gauge | 1.5mm/year |
| Impact Load | Strain gauge | 200kN |
| Temperature | IR sensor | 45°C |
| Noise | Sound meter | 82dB |
| Vibration | Accelerometer | 8g |
Environmental Considerations
| Condition | Requirement | Solution |
|---|---|---|
| Cold Climate | Anti-icing | Heating system |
| Hot Climate | Expansion | Gaps/Joints |
| Wet Areas | Drainage | Channels/Slots |
| Corrosive | Protection | Coating/Treatment |
| High UV | Stability | UV resistant |
