1. Sperry Rail International
A Rockwood Company
Sperry Rail International
A Rockwood Company
Ultrasonic Testing of Rail
Bob Crocker
2. Sperry Rail International
Overview A Rockwood Company
• Rail is an engineering structure
like many others
• Strength and stiffness based on
material properties and shape
• However, introduce a sharp
tipped crack as a stress
intensifier and all bets are off
• Huge holes have no effect as
long as the radius is large
5. Sperry Rail International
A Rockwood Company
Network Rail Infrastructure
• Network Rail owns approximately 21,000
miles of track, therefore 42,000 miles of rail
• This comprises of approximately 16,000 miles
of continuously welded rail (CWR) and 5,000
miles of jointed track, so millions of welds
and bolted joints
• This includes approximately 35,000 switch
and crossing (S&C) units.
6. Sperry Rail International
A Rockwood Company
The Facts of Life for a Railway
• Cracks can occur anywhere at any time
• 42000 miles and 35000 S&C to cover
• The only way to avoid cracks in railway
rails is to stop running trains !
7. Sperry Rail International
A Rockwood Company
The Facts of Life for an NDT Man
• It is a peculiar irony which is often
overlooked, even by the NDT community:
– We can’t find a crack until it is there
• Therefore the task is:
– We have to find cracks between point of
creation and before they cause the rail to break
8. Sperry Rail International
A Rockwood Company
Background
• Hither Green disaster November 1967
• Section of rail at a bolted joint came away
• Caused by cracks growing from bolt holes
• Realisation that cracks too small to be
detected by visual inspection could cause
catastrophic failure
• Real NDT arrived
16. NDT Philosophy Sperry Rail International
A Rockwood Company
• Objective:
– find everything
– test it often
– pre-emptive crack detection
– defect management to replace crisis recovery
• How:
– comprehensive ultrasonic inspection
17. Sperry Rail International Sperry Rail International
A Rockwood Company
Who are we ?
• The Worlds First Company to Provide the
Railways with a Rail Flaw Detection Service
• Worlds Largest Rail Inspection Company
• Over 65 Years Experience in Rail Flaw Detection
• An Expanding Fleet of over 120 vehicles
The Only Company Totally Focused
to Rail Flaw Detection
19. Customer Base Sperry Rail International
A Rockwood Company
• Europe North America
– Network Rail (UK) Amtrak
– LUL (UK) BNSF
– Sweden CSX
– Norway Norfolk Southern
– Germany Canadian Pacific
– Estonia Canadian National
– Finland New York Subway
– Switzerland
– Spain
• India
• China
• Australia
37. Sperry in India Sperry Rail International
A Rockwood Company
Organisation - Equipment
38. Sperry Rail International
A Rockwood Company
Rail Inspection Process
• Vehicle runs along a route selected by the railway
organisation and gathers data about features (“suspects”)
in the rail
• The data is analysed according to defined standards
• Reports are sent out to staff “on ground” via internet.
• They verify “suspects” to confirm them as “defects” using
walking sticks to defined standards.
• Verification Reports are transmitted back via internet
• Verified data used to compile run-on-run analysis
39. Sperry Rail International
A Rockwood Company
Route Verification
• All our data is tagged with a satellite location
(GPS)
• We take the list of satellite locations recorded at 5
second intervals and superimpose them on a
detailed map of the network
• This has the intended route marked on it and we
can see where we were diverted off route
40. Which Track ? Sperry Rail International
A Rockwood Company
42. Sperry Rail International
A Rockwood Company
Data Analysis
• We use 9 probes on each rail
• We store the ultrasonic response from every probe every
5mm interval along the rail
• We construct a side view of the rail using the ultrasonic
data. This is called the B-scan
• We can scroll through every test using the stored records.
• The analyser is trained to look for characteristic patterns
in the data and the process is aided by machine-based
algorithms
• Most suspects produce a response on more than one of the
probes which increases confidence in the data because
every probe is independent of every other probe
43. B-scan Analysis Sperry Rail International
A Rockwood Company
44. B-scan Presentation
Tache Ovale Sperry Rail International
A Rockwood Company
49. Verification Sperry Rail International
A Rockwood Company
•Verification carried out by NR personnel
•Staff directed to the site of a suspect using the
railway mileage and GPS in the reports
•They use a Sperry walking stick and hand-held
probes to confirm the suspect as a defect (or not)
•Procedures have been established to ensure
uniformity of reporting
•Often track features give an ultrasonic response
but are not a defect. These are entered into the
“features” database to create an inventory of
track features.
•All this information is fed back to the analyser
on the next inspection run
50. Defect Database Sperry Rail International
A Rockwood Company
52. Repeated
Sperry Rail International
A Rockwood Company
Objects
53. Analysis – Run-on-Run View Sperry Rail International
A Rockwood Company
• Gives the user
an overview of
tests of a section
of track over a
period of time
• Provides a visual
indication of the
location and
severity of
suspects and
defects
• Indicates gaps in
testing
54. The Integrated Process
Compliant Track Analysis Sperry Rail International
A Rockwood Company
Start 1. B-Scan Analysis
2. Route Validation
Create Base 3. Suspect Reporting
Track Map 4. Verification Feedback
5. Verification Validation
Pre-Compliance
6. Twin View Analysis
Process
x3 7. RMO Identification
NR / Sperry Min 8. BMO Identification
Defect Audit 9. Compliance Rev Meeting
10. NARMO Identification
NO 11. BMO / RMO Growth Analysis
3 Audits
OK
YES
Compliant Verification only of new indications or
Track Indications that are growing / changing
End
55. Data becomes Information
The Integrated Approach Sperry Rail International
A Rockwood Company
to Defect Management
Track Insp
Freq
Rail Test Proc
Management Standards
Binders
Detection Standards
Calibration
Location
Rail Inspection
Database Process
Reporting /
Verification
56. Sperry Rail International
Summary A Rockwood Company
• Frequent, comprehensive ultrasonic inspection
of the whole rail cross-section of plain line,
welds and joints.
• Population of a Defect Database that turns data
into Management Information
• Pro-active defect management, rather than
reactive crisis recovery
57. Sperry Rail International
This is what it is all really about A Rockwood Company
Number Of Broken Rails
1000
800
600
Number Of
400 Broken Rails
200
0
1999 2000 2001 2002 2003 2004
Year
“The lowest number of broken rails in the UK railway’s
history”
