• 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
Sperry Rail InternationalA Rockwood Company
Sperry Rail InternationalA Rockwood Company
Sperry Rail InternationalA 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 • 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.
Sperry Rail InternationalA 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 !
Sperry Rail InternationalA 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– 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
Sperry Rail InternationalA Rockwood Company
Background• Hither Green disaster November 1967 • Section of rail at a bolted joint came away• Caused by cracks growing from bolt holes• 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
Sperry Rail InternationalA Rockwood Company
Ultrasonic inspection is used to locate and identify all the major defect types in rail.
• Objective:– find everything– test it often– pre-emptive crack detection– pre-emptive crack detection– defect management to replace crisis recovery
• How:– comprehensive ultrasonic inspection
Sperry Rail InternationalA Rockwood Company
• The Worlds First Company to Provide the Railways with a Rail Flaw Detection Service
• Worlds Largest Rail Inspection Company
Sperry Rail InternationalWho are we ?
• Over 65 Years Experience in Rail Flaw Detection• An Expanding Fleet of over 120 vehicles
The Only Company Totally Focused to Rail Flaw Detection
Sperry Rail InternationalA Rockwood Company
Sperry Rail International -We’ve been around awhile
Sperry has been inspecting rail since 1928 using a combination of magnetic induction and ultrasonics.
Sperry Rail InternationalA Rockwood CompanyCustomer Base
• Europe North America– Network Rail (UK) Amtrak– LUL (UK) BNSF – Sweden CSX – Norway Norfolk Southern – Norway Norfolk Southern – Germany Canadian Pacific – Estonia Canadian National– Finland New York Subway– Switzerland – Spain
• India • China• Australia
Sperry Rail InternationalA Rockwood Company
Ultrasonic inspection is used to locate and identify all the major defect types in rail.
Sperry Rail InternationalA Rockwood Company
Horizontal Defects(0 Degree)
A B EDC
A B C D E
Ultrasonic beams are transmitted into the rail at a number of angles. Each angle is chosen to enable detection of specific defect types. This illustration shows a 0 or “Zero” degree probe angle which sends a beam verticlaly downwards through the rail. Sound reflects from the bottom of the rail(good) or from cracks (bad). The lower rectangles show the flaw detector display which an operator interprets to identify and classify from the various defects.
Sperry Rail InternationalA Rockwood Company
Transverse DefectsTache Ovales
(0 and 70 Degree)A B A B
A B A B
This illustration shows the probe angle of 70 degrees which is designed specifically to detect transverse, or tache ovale, defects in the rail head. Sound is directed into the rail so it is normal to orientation of the defect to give maximum reflection. The zero degree probe may also give an indication by exception if the defect blocks the path of the sound to and from the foot of the rail.
Sperry Rail InternationalA Rockwood Company
Hole-in-the-Web Defects(37 Degree)
EC DA B
A B C D E
This illustration shows the 37 degree probes which are designed to examine holes in the web. The main holes are bolt holes but there are many others in practice all of which can give rise to cracking. Cracks are almost always generated at 45 degrees to the vertical, or they can be horizontal. Once again this is determined by the stress regime. The combination of two 37 degree probes and the zero degree probe will locate a crack in any orientation.
Sperry Rail InternationalA Rockwood Company
Sperry Roller Search Unit (RSU)
Sperry has develop a wheel containing nine separate ultrasonic probes: one zero degree probe three forward looking 70 degree probes three reverse looking 70 degree probes one forward looking 37 degree probe one reverse looking 37 degree probe The assembly is known as a Roller Search Unit or RSU
Sperry Rail InternationalA Rockwood CompanyRSU on Rail
The RSU is held in a frame on the vehicle and is pressed in to contact with the rail surface.
This vehicle is used to test rail in Sweden, Norway, Germany, Estonia, Latvia and Lithuania. It can test both rails simultaneously at speeds up to 40 mph. All data is recorded by on-board systems.
Sperry Rail InternationalA Rockwood Company
Sperry UTU 5
Sperry Rail InternationalA Rockwood CompanySperry Land Rover
Sperry Rail InternationalA Rockwood Company
Cometi
Sperry Rail InternationalA Rockwood Company
Service Loco
Sperry Rail InternationalA Rockwood Company
Sperry Walking Stick
Sperry Rail InternationalA Rockwood Company
The Usual Pose
Sperry Rail InternationalA Rockwood Company
Testing in Norway
Sperry Rail InternationalA Rockwood Company
Testing in Norway
Sperry Rail InternationalA Rockwood Company
Sperry in India
Organisation - Equipment
Sperry Rail InternationalA 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
Sperry Rail InternationalA Rockwood Company
Route Verification• All our data is tagged with a satellite location (GPS)
• We take the list of satellite locations recorded at 5 • 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
Sperry Rail InternationalA Rockwood Company
Which Track ?
Sperry Rail InternationalA Rockwood Company
Route Verification
This illustration shows the presentation of the data from all the probes on the vehicle. The left rail in in the upper part of the display and the right in the lower. This example shows a bolt hole crack. The superimposed sketch shows the origin of the various signals seen on the B-scan. Pattern recognition algorithms on the train will identify this as a bolt hole crack but at present the computer-based recognition systems are always backed up by a further expert system called a “human being” ! The location of the origin of this ultrasonic response is stored with the B-scan so that the railway owner or maintenance contractor can be directed to action it.
Sperry Rail InternationalA 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-scandata. 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
Sperry Rail InternationalA Rockwood Company
B-scan Analysis
This illustration shows the presentation of the data from all the probes on the vehicle. The left rail in in the upper part of the display and the right in the lower. This example shows a bolt hole crack. The superimposed sketch shows the origin of the various signals seen on the B-scan. Pattern recognition algorithms on the train will identify this as a bolt hole crack but at present the computer-based recognition systems are always backed up by a further expert system called a “human being” ! The location of the origin of this ultrasonic response is stored with the B-scan so that the railway owner or maintenance contractor can be directed to action it.
Sperry Rail InternationalA Rockwood Company
B-scan Presentation Tache Ovale
This illustration shows the presentation of the data from all the probes on the vehicle. The left rail in in the upper part of the display and the right in the lower. This example shows a bolt hole crack. The superimposed sketch shows the origin of the various signals seen on the B-scan. Pattern recognition algorithms on the train will identify this as a bolt hole crack but at present the computer-based recognition systems are always backed up by a further expert system called a “human being” ! The location of the origin of this ultrasonic response is stored with the B-scan so that the railway owner or maintenance contractor can be directed to action it.
Sperry Rail InternationalA Rockwood Company
B-scan Presentation Star Crack
This illustration shows the presentation of the data from all the probes on the vehicle. The left rail in in the upper part of the display and the right in the lower. This example shows a bolt hole crack. The superimposed sketch shows the origin of the various signals seen on the B-scan. Pattern recognition algorithms on the train will identify this as a bolt hole crack but at present the computer-based recognition systems are always backed up by a further expert system called a “human being” ! The location of the origin of this ultrasonic response is stored with the B-scan so that the railway owner or maintenance contractor can be directed to action it.
Sperry Rail InternationalA Rockwood Company
B-scan Presentation Squat
This illustration shows the presentation of the data from all the probes on the vehicle. The left rail in in the upper part of the display and the right in the lower. This example shows a bolt hole crack. The superimposed sketch shows the origin of the various signals seen on the B-scan. Pattern recognition algorithms on the train will identify this as a bolt hole crack but at present the computer-based recognition systems are always backed up by a further expert system called a “human being” ! The location of the origin of this ultrasonic response is stored with the B-scan so that the railway owner or maintenance contractor can be directed to action it.
Sperry Rail InternationalA Rockwood Company
B-scan Presentation Vertical Longitudinal Split
This illustration shows the presentation of the data from all the probes on the vehicle. The left rail in in the upper part of the display and the right in the lower. This example shows a bolt hole crack. The superimposed sketch shows the origin of the various signals seen on the B-scan. Pattern recognition algorithms on the train will identify this as a bolt hole crack but at present the computer-based recognition systems are always backed up by a further expert system called a “human being” ! The location of the origin of this ultrasonic response is stored with the B-scan so that the railway owner or maintenance contractor can be directed to action it.
Sperry Rail InternationalA Rockwood Company
B-scan Presentation Presentation Twin View
This illustration shows the presentation of the data from all the probes on the vehicle. The left rail in in the upper part of the display and the right in the lower. This example shows a bolt hole crack. The superimposed sketch shows the origin of the various signals seen on the B-scan. Pattern recognition algorithms on the train will identify this as a bolt hole crack but at present the computer-based recognition systems are always backed up by a further expert system called a “human being” ! The location of the origin of this ultrasonic response is stored with the B-scan so that the railway owner or maintenance contractor can be directed to action it.
•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 •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
Sperry Rail InternationalA Rockwood Company
Defect Database
Sperry Rail InternationalA Rockwood Company
B-scan Presentation Presentation Twin View
This illustration shows the presentation of the data from all the probes on the vehicle. The left rail in in the upper part of the display and the right in the lower. This example shows a bolt hole crack. The superimposed sketch shows the origin of the various signals seen on the B-scan. Pattern recognition algorithms on the train will identify this as a bolt hole crack but at present the computer-based recognition systems are always backed up by a further expert system called a “human being” ! The location of the origin of this ultrasonic response is stored with the B-scan so that the railway owner or maintenance contractor can be directed to action it.
Sperry Rail InternationalA Rockwood Company
RepeatedObjects
Sperry Rail InternationalA Rockwood Company
Analysis – Run-on-Run View
• Gives the user an overview of tests of a section of track over a period of time
• Provides a visual • Provides a visual indication of the location and severity of suspects and defects