In-service testing of rails

1 Scope

This specification applies to testing of in-service rails using a measuring vehicle on Bane NOR tracks. The rails shall be tested for internal and surface defects using Ultrasonic and Eddy current inspection systems

2 Track condition

Ultrasonic and Eddy current rail testing shall be performed on track segments with the following properties / conditions

2.1 Rail profiles

Tabell 2: Rail profiles

• • EN 13674-1
  • Teknisk regelverk: Overbygning/Prosjektering/Sporkonstruksjoner/Vedlegg/Skinneprofiler Ekstern lenke)

2.2 Rail inclination

Rail inclination on Bane NOR network is 1:20.

2.3 Rail grades

The following rail grades exists on Bane NOR network (EN 13674-1):

• R200
• R260 Mn
• R350 HT
• R400 HT

2.4 Rail wear

• The test systems shall be capable of inspecting rail profiles with side wear up to 16 mm.
  • Side wear is measured 15 mm below the intersection of the wear profile and the rail vertical axis.

Forstørr bildet

2.5 Track gauge

The equipment shall be capable of inspecting rails in tracks with gauges up to 1470 mm.

2.6 Schwitches and crossings

When testing through turnouts, satisfactory measurement results are expected throughout the turnout except for:

• Areas of switch blades where the full rail-head width is not present.
• Areas of frogs/crossings within 3 meters before and after the physical crossing point.

2.7 Corrugation on running surface of the rail

Test performance shall not be affected by irregularities in the rail longitudinal profile within the limits specified in Tabell 3.

Tabell 3: Corrugation

2.8 Jointed Track

• The test systems shall be capable of inspecting jointed track at an test speed of at least 30 km/h.
• Jointed track is defined here as track with an average spacing of bolted joints down to 15 meters (calculated over 1000 meters).

3 Requirements for Ultrasonic testing

3.1 Ultrasonic probes

The ultrasonic rail testing shall be performed using the following minimum probe configuration for each rail:

• straight-beam probes (0°) 
• angle-beam probes (65-70°)
• lateral angle-beam probes (45-55°) for detection of longitudinal vertical cracks
• angle-beam probes (35-40°) for detection of bolt-hole cracks

3.1.1 Probe Alignment

The inspection vehicle shall be equipped with a mechanism ensuring that the probes are correctly positioned relative to the rail running surface and the longitudinal centerline of the rail.

3.2 Qualification

• Before and after completion of a test campaign, the ultrasonic test system shall be qualified using a reference track with reflectors as specified in 3.2.1 - Reference Track
• The test speed during qualification shall correspond to the planned operating inspection speed on Bane NOR tracks.
•  The detection capability of the ultrasonic rail inspection system shall be assessed according to EN 16729-1 chapter 5.  The results of at least four consecutive test runs through the reference track shall correspond with the size, type, and location of the reference reflectors.
• The positioning accuracy of the ultrasonic rail inspection system shall be assessed according to EN 16729-1, chapter 6.

3.2.1 Reference Track

The reference track shall as a minimum contain the following artificial reflectors according to EN 16729-1, table 1 and annex A

3.3 Functional Testing

• Procedures shall be established for daily calibration of probes and instruments.
• The supplier shall carry out calibration in accordance with these procedures immediately before each inspection shift, after system modifications, and after replacement of components.

3.4 Detection Reliability

• During inspection of Bane NOR tracks, the ultrasonic rail inspection system shall detect and report at least 80% of rail defects present in the track that fall within Defect Groups 0, 1, or 2. Feilgrupper.
• Detection reliability shall be verified through random checks using manual inspection equipment.

3.5 Hitrate

At least 70% of reported potential defect locations shall be verifiable. Hit rate shall be verified through follow-up inspections using manual equipment.

3.6 Classification of Defect Indications

3.6.1 Defect type

Defect indications shall be classified using codes in accordance with EN 17397-1.

3.6.2 Defect Groups

Detected defects shall be classified into three groups according to Defect Groups 0, 1, and 2. In addition, the object in which the defect is located shall be identified in accordance with Object Classification.

3.6.2.1 Defect group 0

The following defects shall be classified as Defect Group 0:

• Broken rails, i.e., rails split into two or more pieces, or rails where a fracture piece has detached leaving at least 50 mm of the running surface missing to a depth of at least 10 mm.
• Vertical cracks extending through the full height of the rail head.
• Horizontal cracks extending through the full width of the rail head.

3.6.2.2 Defect group 1

Defects specified in Tabell 4 shall be classified as Defect Group 1.

Table 4: Defect group1

3.6.2.3 Defect group 2

Defect specified in Tabell 5 shall be classified as Defect Group 2

Table 5: Defect group 2

3.6.3 Classification of Object

The object in which the defect is located shall be identified using the following object codes:

• On rail
• Alumino-thermic weld
• Flash-butt weld
• Electric arc weld
• Bolted joint
• Insulated joint
• Expansion joint
• Crossing nose
• Switch blade
• Frog (crossing)

3.7 Reporting

Defect indications falling within Fault Group 0, 1, or 2 shall be reported. The following reports shall be submitted for each shift:

• Shift report
• Measurement results: all defect indications shall be uploaded to Bane NOR’s server in accordance with the Data Import Specification.
• For each shift the contractor shall deliver odometer data (kilometer reference) and GPS data continuously for the full movement of the measurement vehicle. This shall be directly linked to the reporting of defects.

3.7.1 Test Results – Electronic Reporting

For each individual defect location, the contractor shall collect and transmit the following data to Bane NOR’s server:

• Line number
• Kilometre reference (km)
• GPS coordinates
•  GPS quality indicator  
• Rail string (right or left in the direction of increasing kilometre values)
• Distance from a reference object (bridge, turnout, kilometre marker, etc.)
• Defect group
• Defect code according to   EN 17397-1 
• Identification of probe(s) detecting the defect
• Defect length in the longitudinal direction of the rail (mm)
• Defect depth at the beginning and end of the defect (mm from rail top)
• Amplitude indication for transverse cracks
• Graphical presentation of the defect (B-scan image)
• Any comments

Complete specification of the data to be transmitted to Bane NOR’s server (Data Import Format).

3.7.2 Accuracy Requirements – Defect Location Positioning

• The location of defects shall be reported with an accuracy of no more than ±1 m from the actual defect location.
• Defect locations shall be reported using GPS coordinates in addition to kilometre reference.
  
  • GPS coordinates are not required in tunnels or other locations where GPS signals cannot be received.

3.7.3 Reporting Deadline

All defect locations shall be uploaded to Bane NOR’s server no later than 48 hours after a track section has been tested.

3.7.4 Marking of Defect indication in the Track

Defects classified as defect Group 1 in accordance with Section 4.2 shall be marked with white paint on the rail. The distance between the marking and the defect shall not exceed 1 m.

3.8 Qualification of personell for ultrasonic testing

• The test vehicle operator shall be certified to Level 2 in ultrasonic testing in accordance with EN 16729-4 or equivalent.
• Personnel responsible for analysing and reporting results shall be certified to Level 2 in ultrasonic testing in accordance with EN 16729-4 or equivalent.
• Operators and analysis personnel shall be able to document training in rail inspection.
• The contractor shall prepare a procedure (work instruction) for rail testing using the measuring vehicle and for the analysis of inspection results. This procedure shall be reviewed and approved by Bane NOR before testing commences.

4 Requirements for Eddy current testing

4.1 General

Eddy current testing shall be performed in accordance with EN 16729-2.

4.2 Inspection area

Eddy current testing shall inspect for surface cracks in the rail running edge and rail running surface within the area from -45° to +10° according to EN 16729-2, figure 1 and figure 2.

4.3 Defect types

Eddy current testing shall inspect the rail surface for the following rail defect types according to EN 17397-1:

• Head checks (1223, 2223)
• Squat (127, 227, 417, 427, 437)
• Spalling (1211, 2211)
• Flaking (1221, 2221)
• Shelling (1222, 2222)

4.4 Defect size

The Eddy current testing system shall be capable of determine the crack depth down to minimum 3 mm below the running edge/surface of the rail.

4.5 System verification

Before and after completion of a test campaign, the Eddy current testing system shall be verified according to EN 16729-2, Annex A

4.6 Testing speed

Eddy current testing shall be performed together, and with the same testing speed, as for the ultrasonic rail testing.

4.7 Reporting

The following reports shall be submitted for each shift:

• Shift report
• Measurement results: all defect indications shall be uploaded to Bane NOR’s server in accordance with the Data Import Specification.
• For each shift the contractor shall deliver odometer data (kilometer reference) and GPS data continuously for the full movement of the measurement vehicle. This shall be directly linked to the reporting of defects.

4.7.1 Test results

The contractor shall collect and transmit the following data to Bane NOR’s server:

• Line number
• Kilometre reference
• GPS coordinates 
• GPS quality indicator 
• Rail string (right or left in the direction of increasing kilometre values)
• Scanning direction
• Identification of probe(s) detecting the defect
• Position of the probe(s) in relation to the rail profile
• Indication of crack density (#cracks/meter)
• Indication of maximum crack depth
• position of defects on the rail head
• lift off events and/or non testable areas
• Any comments

4.8 Qualification of personell for Eddy current testing

• The test vehicle operator shall be certified to Level 2 in Eddy current testing in accordance with EN 16729-4 or equivalent. 
• Personnel responsible for analysing and reporting results shall be certified to Level 2 in Eddy current testing in accordance with EN 16729-4 or equivalent.
  Operators and analysis personnel shall be able to document training in rail inspection.

5 Reference Documents