Technical Proposal
Ultrasonic Automated Cracked Wheel Detection System
(ACWDS)
Nanjing Tycho Information Technology Co Ltd
A subsidiary of CHSR
Background
• Wheel is a critical part on the train. Wheel’s conditions in the aspects of its profile and internal conditions
may have profound influence to the train operation, passenger’s comfort, and the risk of safety of the
train and the infrastructure of railway line and trackside facilities.
• Presently, In normal operations either in the train/car depot/yard or on the operation mainline, to quickly
inspect the wheel defects would be a difficult issue. Seldom method can be applied all over the world.
Manual inspection with ultrasonic instruments to check the wheel one by one takes a lot of labor cost
and long period even for a single car. In actual operation, it is not possible to check all the wheels by
daily, even not possible by weekly or monthly either.
• To resolve this trouble matter and improve the wheel detection efficiency and reduce the working
strength and save the detection time, finally keep the railroad operation safer and reduce the operation
risk caused by condemnable wheel, ACWDS was developed.
• ACWDS is an online wheel detection system to detect the defects in the wheel. With ACWDS, it can
detect all the wheels on more than one hundred of cars in couple of minutes. Comparing with the low
efficiency of manual inspection, ACWDS lowers down greatly the working strength of inspectors’ and
improve the inspection rate greatly.
• ACWDS is a product to resolve the requirements of quick and accurate inspection to the wheels
dismounted on the cars.
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Brief Introduction
• Automated Cracked wheel Detection System (ACWDS) is a trackside automatic cracked wheel detection system
installed along the test track to detect the defects in the wheel rim working on the specially designed test track.
• The test track is a patented special wide-gage track which leaves the rolling circle area clear when the wheels run
over ACWDS. Meanwhile, working with an outside-cut normal-profile rail where the wheel field area is left clear for
inspection using probes, ACWDS covers the complete tread area’s inspection.
• ACWDS use the contact detection method by contacting the probe surface to the wheel tread surface. For reducing
the attenuation of the ultrasonic wave in the air, coupling agent (water) is applied.
• ACWDS will produce the detection result in less than one minute after the train passes over ACWDS. ACWDS has
the functions to send the alarm message of test report with defects information to the person appointed by the
customer.
Note:
The description in this document may be different from the final design. The final design is subject to the latest design and final
confirmation by the customer.
System in USA
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Wheel Detection with Train Passing
Brief Introduction
Train runs over the system. The train wheel tread contacts with the probes. The water sprays on the wheel tread and the probes surface for
better coupling to help the ultrasonic wave penetrating the wheel for detection.
At the speed of 15kph of the train passing over the system, it will take less than 2 minutes to inspect all the wheels of the train with 20 cars.
And the test result will pop up in less than 1 minute.
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Advantages of ACWDS

Automatic Detection and No Personnel Attendant
ACWDS is a fully automatic system for online wheel detection of internal defects in the rim and disc.

Quick Detection Result Display
As train passes over the system, ACWDS software starts to collect and process the data. In less than 1 minute after
train passes over ACWDS, the test result can be displayed to the customer’s display terminal anywhere with network
connection.

Automatic Alarm
ACWDS will send out its alarm information with relevant report in case of defects detected to any appointed person by
message or email.

Bi-Directional Train Reception and Detection
ACWDS can detect the wheel when the train enters the system from both sides.

Environmental Friendly
ACWDS is an environmental friendly system working at trackside. It complies with CE standard for railway application.
Meanwhile, no harmful material is used in the manufacturing and in operation, there is no harmful substances produced.
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Working Principle
• The basic working principle is as below pictures shown.
1. Wheels running on the track and pass over the system at certain constant speed.
2. The wheel trigger the UT instrument and ultrasonic probe transmits the ultrasonic signals and receives the echo (pitchcatch mode).
3. Ultrasonic raw data is collected to database server for analysis of software. The software will be as collecting the data and
processing the data, which saves the data processing time to generate the detection result quickly.
4. With probe arrays, the system covers the full wheel rim area.
5. After train passes, the system returns to standby status for next train.
a. Wheel running on the
probe array
b.. Ultrasonic beam
penetrating in the wheel
c. Probe array cover the complete
wheel rim and upper part of wheel disc
Principle of Operation of Ultrasonic wave
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Working Principle

When the train enters from either side of the system, the photocell sensors will wake up the system and trigger
the system to be ready for detection.

Trackside Cabinets (e.g. A1, A2, A3,A4 below) control the ultrasonic transmitting and receiving of the ultrasonic
probe. Meanwhile, the collected ultrasonic raw data will be sent to the server for software analysis.

When train leaves the photocell sensors on the other side of the system, the system will be shut off to standby
status for next train entry.
Note: the actual equipment may be different from the schematic here. The design and configuration of the system is subject to the
customer’s requirements and the conditions of the wheel and train car.
Schematic of trackside UT control
boxes and probe array
Schematic of Trackside Equipment
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Composition and
Function
In structure, ACWDS includes below sub-systems:
1. Concrete Slab Foundation and Track work
2. Trackside Electrical Cabinet
Schematic of ACWDS Trackside
equipment
3. System Triggering Devices
4. Ultrasonic Detection Probe Array
5. Trackside data acquisition boxes
6. Couplant supply and recycling loop
7. Network and Software
8. AEI module
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Trackside facilities
1. Concrete Slab Foundation and Track work
• ACWDS is seat on a concrete slab, instead of ballast, which ensures the influence of vibration from the wheel and rail when train
passes over.
• To ensure the complete coverage of the wheel rim area, ACWDS uses a patented widened track design that leaves the space for the
probe array to detect the rolling circle area. Meanwhile, ACWDS includes a special cutout rail to leave the space for the ultrasonic
probe array to cover the wheel field area.
• The guard rail is to keep the wheels over the system centered to the tracks.
• The concrete slab with the curb around the track makes sure the sprayed water or other couplant can be re-collected for recycling.
• Option: Tycho can provide the detailed trackwork design to the client for its convenience of supply of special track and construction of
the foundation and trackwork. Or, if the supplier is not available for the client locally, the supplier can supply the special track at the
client’s cost. However, the installation of the special track is still the job of the client’s.
Note：the design of trackwork is patented and Tycho’s IPR.
Schematic of Trackwork
2. Trackside Electrical Cabinet
• Functions:
Trackside Electrical Cabinet is to control the logic
relations of the trackside equipment, and supply the power to
each equipment.
• In the trackside electrical cabinet, it includes:
1.Comprehensive control board;
2.Power supply unit;
3.Network switch
4.Pump control unit;
5.AEI Data Converter;
Trackside Electrical Cabinet
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3. System Triggering Device
• System Triggering Device can be various in actual application. It
senses the train presence to wake up the system for detection.
• There are two pairs of photoelectric sensors on entry and exit of
the ACWDS. One of each pair is a transmitter and the other one is
a receiver. Normally, these two photoelectric sensors are
connected with a light beam. When a train passes between these
sensors, the light beam is blocked by the train body.
• Any pair of photoelectric sensors can be entry triggering sensors
or exit triggering sensors. The pair is triggered first will be
regarded by the system as the entry sensors. The other pair will
be the exit sensors for shutoff of the system.
A pair of photoelectric sensors
• Option:
Considering the customer’s preference for train presence
detection sensor, other types of triggering system may be
considered, such as magnetic wheel sensor, etc.
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Magnetic Wheel Sensor
4. Ultrasonic Detection Probes and Wheel Sensors Array





Ultrasonic Probe is an important part for wheel detection. It
sends the ultrasonic signal to the wheel and receive the echo.
During the detection, it is required that the train speed shall be
constant so that the triggering time of each probe can be
accurate. However, it is not possible to control the train running
in certain speed without any fluctuation. This wheel sensors
array is set to test the train speed and calculate the triggering
time and accurate synchronization between the wheel and its
contact probes.
From the picture on the right, it is seen that three lines of probes
were set, two lines for rolling area and one line for wheel field
area detection to cover the complete wheel rim area.
Due to not receiving any technical requirements from the client,
and considering the application for Tram, the average wheel
diameter of about 550mm is used for the proposal.
Two revolutions of wheel detection are to be supplied for this
proposal. The dual elements straight probes will be used only for
the system to focus on detection around the wheel tread rolling
area.
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Probes and Wheel Sensors Array
5. Trackside Data Acquisition Boxes
• Connecting with the probes, in the Data Acquisition Box, ultrasonic control board is set for controlling
the transmitting and receiving of the ultrasonic wave.
• Apart from the probes arrays controlled, acquisition box is connecting also with the wheel sensors.
There are scores of wheel sensors on one side that sense the wheel and test the wheel speed
accurately. The wheel sensors help find the proper time when the wheel is exactly on the probe
surface to trigger the ultrasonic wave for detection.
• A group of wheel sensors will be set a certain distance in front of the probes. When the wheel is
running on the test track, the preset wheel sensors will tell the system when the wheel will be on the
first probe. Based on the calculation, It sends the signal to the board to trigger the probes. the probes
are controlled to transmit the ultrasonic into the wheel and receive the echo. Meanwhile, those raw
data will be collected by the acquisition boxes and transferred to the server in electrical cabinet.
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6. Couplant Supply and Recycling Loop
• Ultrasonic wave attenuates very quickly in the air. For Ultrasonic
transmission between different materials, to get a better result, the
coupling is every important and required.
• To save the couplant and make the detection more economic,
water will be used for the coupling agent.
• Further, thanks for the concrete foundation, it is available to use
the water repeatedly by recycling. Apart from the water taken away
by the wheels during detection, 85% of the water can be recycled
and reused.
Couplant Supplying and Recycling Loop
• If it is possible, it is recommended to connect the tap water pipe to
the supplying tank. The system can automatically refill the tank in
case of water level is low.
• In winter, if the environment temperature is lower than -5℃, antifreezing agent may be required to keep the water from being
frozen.
• As per the site’s climate conditions in a year period, heating
system can be integrated into ACWDS to keep the system warm
for normal operation.
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Water Spraying
7. Network and Software
• Network
1.
For data transmission, the network from trackside to the server is
required.
2.
ACWDS is available for remote connection by internet access.
With internet, the operator can have the access to the system
anywhere, any time all over the world.
3.
Remote connection is for data review, result confirmation, and
manual involvement (if required).
4.
With network supplied by the customer, the raw data and test
result can be sent to the customer’s information center for storage,
review, and statistics, which can provide reliable evidence and
track the development of the defects.
5.
Minimum bandwidth of internet: not less than 5M.
6.
To protect the data, the system has access authorization. Only
authorized person can have the right for data review, and other
activities on the software.
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General Structure of network
8. Software Interface
• Monitoring Interface
This monitoring interface is started by the monitoring software
installed on the server computer. Once the system is started, the
monitoring software will be started automatically. The monitoring
interface shows the system status and the communication between
the wayside devices and the server.
• Analysis Software
Analysis Software is responsible for the data analysis, result
display, result report print, and historic data review. Meanwhile, the
comparison of historic data can be displayed additionally for the
wheel crack development trend statistics and the wheel life span
prediction.
With advanced elaborating algorithm, the software works in
very high efficiency. The data process is going as the train running
over the system. The test result is available immediately in 1 minute
after the train passing.
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Interface of System Monitoring Software
8. Software Interface
• Software has the authorization limit for the authorized person only.
• This interface shows list all the train detected as per time stamp of the
system and the alarm status of the wheel on the corresponding train.
• Click into the alarm column, a wheel pie will show the quantity of the
defects detected. And detailed information such as the defects type,
depth, etc. will be displayed also. On the right side of the screen, it shows
the actual ultrasonic wave echo or the defects wave.
List of Train Detected
• The alarm can be classified into different levels as per the customer’s
criteria. For critical alarm, software will generate the report and send
automatically to the appointed person from the customer by email or
message.
• With the complete data record, it is easy to review the historic record of
the wheel conditions of each passage on the system. In this way, it is
possible to see the wheel conditions and the development trend of the
defects on the wheel. It gives the customers the opportunity to focus
certain special wheel.
• From the picture below, it is found the difference between defects
detected.
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Single Wheel Alarm Indication
8. Software Interface
Different Alarm Level
Examples:
(a) VSR Wheel;
(a) Gouged Wheel;
(c) Wheel with Multiple
Subsurface Fatigue cracks.
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Result Output
• ACWDS will generate a simple test report. An example of the report is shown below.
• In the report, the probe with functional problem will also be included for the operator’s reference to change.
• The format of the test report can be customized as per the customer’s requirements.
• The data format can be customized as per the customer’s requirements for data uploading and review.
An example of Simple Report
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Installation, Test and Commissioning and training
• After delivery, Nanjing Tycho supplies the installation service with installation manual.
1. The system is better to be installed on the straight track line. At least, the in the front and back of the
installation location, there are 100 meters of straight line.
2. The system meet the requirements of out-door operation. However, it is possible, an installation in the
tent is recommended for the interest of maintenance activities.
• Nanjing Tycho will be responsible for the test and commissioning service.
1. The test and commissioning may take 3-5 working day to make sure the system functioning well.
2. Nanjing Tycho will provide the test and commissioning plan that indicates the main activities involved.
The test and commissioning procedures may vary as per the customer and the actual train operation and
maintenance activities.
3. Remote connection is available to access the system for diagnosis and data review.
• Training
1. Nanjing Tycho will be responsible for the training to the end user up to 5 persons. A training document
will be provided to the trainee for better understanding to the system.
2. The customer shall provide the classroom, desk and chairs, and any convenient facilities for training.
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Technical Parameters
• Ambient Conditions
1. Environmental temperature: -20℃ - +45℃; if the temperature is lower than -5℃, the anti-freezing agent may be required for better
coupling condition.
2. HR: ≤95%；
• Sensitivity
1. Probe Sensitivity：2mm FBH；
2. System Detection Sensitivity：it is related to the train speed and can be tuned as per the customer’s operation standard for wheel.
• Defects type to detected:
1. Vertical Split Rim;
2. Sub-surface delamination;
3. Fatigue crack, etc.
4. Circumferential crack;
• Detection Depth: 3-70mm depth into the wheel rim and disc from the tread surface, to detect disc defects is subject to the profile of the
wheel disc.
• Train Speed: not more than 20kph. The lower speed, the better detection accuracy.
• Power and Electricity
1. Power: 15kW
2. Electricity: 230V+/-10%; 50/60Hz
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Scope of Supply
• Nanjing Tycho’s Scope of Supply:
1. Design, manufacturing, delivery, installation, test and commissioning of ACWDS Equipment;
2. Training to the customer’s operator
3. Design of Concrete Slab and special trackwork conditions and site inspection after track done.
4. Option: Design of the civil foundation conditions and supply of the special track.
5. All required documentation for ACWDS operation and maintenance;
6. Shipment transportation by sea and customs declaration at China’s seaport;
• The Customer’s Scope of Supply:
1. Civil construction of Concrete Slab, special track and the installation of special track;
2. Option: Civil Construction of Concrete Slab and the installation of special track;
3. Trackside facilities including tap water (if available), electricity, Internet; to provide the access of these facilities to the
track side at site.
4. Trackside plant room (Bungalow);
5. Customs Clearance at the Destination Sea Port and inland transportation at the destination country；
6. AEI equipment and the data interface to collect the car number and wheel position information.
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