CONCEPT AND WORKING OF WILD (Wheel Impact Load Detector)
- 1. 1 CONCEPT AND WORKING OF WILD_____________________________________ What is ‘WILD’: It is a set of instrumented rails (strain gauged) through which data acquisition (impact of load) for wheels of trains under moving conditions at all speeds is done and processed for further report generation. Need of WILD in Railways Defective rolling stock produce high impact loads. These loads over a prolonged period of time leads to Rail/Wagon failure, wheel bearing failure etc. WILD measures impact load independent of the cause. WILD system assists railway engineers to attend to the defective rolling stock immediately. Reduces Service Failures and Unplanned Maintenance Cost of Rolling Stocks & Tracks. WILD is used to catch the defects in the early stage and thereby protecting Rail Infrastructure & avoids Catastrophic Failures. Defects that can cause High Impact Load Unevenness in Side Bearer Wheel Flat Broken Spring Dashpot Oil Leak Cone Defect Bolster Spring Axle Box Cant Friction liner PU Pad (List of defects Released by RDSO on 23rd March 2011) Components of WILD Instrumented Tracks Signal conditioning unit Train Trigger Sensor Real time Embedded controller Impact Load Analyzer Software Wireless data transfer Power back up Calibration Setup Features & Concept of WILD WILD uses instrumented rails. Tracks are instrumented with strain gauges (18 Nos) to measure the load pattern of the wheel on the rail. The strain gauges are placed such that three revolutions of a wheel are covered. As wheel rolls over the rail various portions of the wheel fall in the effective zone and dead zone (sleepers). The space between sleepers is instrumented using strain gauges and any load that appears in the effective zone is considered. The maximum load measured in the entire instrumented portion is treated as the impact load. The instrumented portions can be determined and prepositioned to give best coverage for the wheels of interest, as per an average wheel dia analysis. Once installed the system’s wheel coverage pattern does not change. K.G. Vipin Kumar
- 2. 2 WILD Site Exit Trigger Sensor Entry Trigger Sensor 18 Channels (L1~L18) Signal Conditioning Modules Real Time Controller Control & Switching Circuits Backup Device Data Transfer EB Power/ Primary Power Solar Power/ Secondary Power WILD Block Diagram AT SITE AT TXR CONTROL ROOM Instrumented Track GPRS 18 Channels (R1~R18) How does it Work? Each strain gauge channel produces a portion of load profile for all the wheels. Accumulating all the data, a complete load profile of the wheel is obtained. The maximum load detected by the channels is primarily used to flag the defective axle/wheel. How does WILD system flag defects WILD system flags the defects purely based on the impact load measured. The limits are set by the RDSO/Railway Board Current limits Maintenance alarm : ILF (Impact Load Factor)>/=2.0 ~ <4.5 Critical alarm : ILF (Impact Load Factor) >/=4.5 The system however features a facility for the end user to set the limits as well. INSTRUMENTED TRACK STRAIN GAUGES ANTENNA CONTROL ROOMAT SITE
- 3. 3 First Left Max Left Load (Tonne) Right Load (Tonne) L1 3.5 R1 3.4 L2 3.2 R2 3.3 L3 2.8 R3 2.9 L4 2.7 R4 3 L5 3.1 R5 3.2 L6 2.9 R6 3 L7 3.1 R7 3.2 L8 3.4 R8 3.3 L9 17.1 R9 11.2 L10 6.1 R10 4.7 L11 3.1 R11 3.2 L12 2.9 R12 3.1 L13 12.4 R13 10.8 L14 2.4 R14 2.5 L15 3.1 R15 3.2 L16 2.9 R16 3.1 L17 3.4 R17 3.3 L18 3.2 R18 3.1 Left Load (Tonne) Right Load (Tonne) L1 3.5 R1 3.4 L2 3.2 R2 3.3 L3 9.8 R3 2.9 L4 2.7 R4 3 L5 3.1 R5 3.2 L6 2.9 R6 3 L7 3.1 R7 3.2 L8 3.4 R8 3.3 L9 17.1 R9 11.2 L10 6.1 R10 4.7 L11 3.1 R11 3.2 L12 2.9 R12 3.1 L13 12.4 R13 10.8 L14 2.4 R14 2.5 L15 3.1 R15 3.2 L16 2.9 R16 3.1 L17 3.4 R17 3.3 L18 3.2 R18 3.1 First Right Max Second Left Max Third Left Max Second Right Max Third Right Max Left Maximum Dy Wheel Load = 17.1 Left Average Dy Wheel Load = 3.27 Left Impact Load Factor = Left Maximum Dy Wheel Load ( 17.1) Left Average Dy Wheel Load (3.27) (Avg. Of Lowest fifteen readings) Left Impact Load Factor (L ILF) = 5.23 Right Maximum Dy Wheel Load = 11.2 Right Average Dy Wheel Load = 3.21 Right Impact Load Factor = Left Maximum Dy Wheel Load ( 11.2) Left Average Dy Wheel Load (3.21) (Avg. Of Lowest ten readings) Right Impact Load Factor (RILF) = 3.49 Left Load (Tonne) Right Load (Tonne) L1 3.5 R1 3.4 L2 3.2 R2 3.3 L3 9.8 R3 2.9 L4 2.7 R4 3 L5 3.1 R5 3.2 L6 2.9 R6 3 L7 3.1 R7 3.2 L8 3.4 R8 3.3 L9 17.1 R9 11.2 L10 6.1 R10 4.7 L11 3.1 R11 3.2 L12 2.9 R12 3.1 L13 12.4 R13 10.8 L14 2.4 R14 2.5 L15 3.1 R15 3.2 L16 2.9 R16 3.1 L17 3.4 R17 3.3 L18 3.2 R18 3.1 System Capabilities Countsnumberof axlesfromvariousmeasurementchannels. Calculatesspeedof eachaxle andthe average speedof train. Identifiesandcountsdefective wheels asperspecifiedthresholdsandratesthemaccording to the severityof defect. Identifiesandcountnumberof Engines,Coaches/WagonsandBrake Vans. Operates24x7 withoutanyhumanassistance. Calculation (WILD-II Ver. 36channel)
- 4. 4 Transmitsrun reportsto a central serverthatcan be accessedbysimple webbrowser*. (*basedonNetworkConnectivityavailableatsite) Can operate froma lowspeedof 30Km/hr. Has solar panel providingapowerbackup. Web Report Demo Reports in WILD The WILD system offers the end user to generate various reports. Month wise, Year wise, Train wise & wheel wise standard reports available. Provision for new standard reports. Summary reports can be drawn out based on Wheel loads Rolling stock (Engine, Wagon, Tanker etc.) Defective rolling stock WILD - Website Usage All the wheel impact loads recorded are stored in the central sever. WILD system is ready but not equipped with Automatic Equipment Identification to enable trending of the Wagon behavior. Nevertheless the WILD website irwild.net offers features for the user to enter the wagon details for the defective wagon along with defect identified. This helps the railways to track the information on the particular wagon as its health declines (from maintenance alarm to critical alarm). WILD System Architecture SMS Notification for Alarm Condition WILD Site Audio Visual at C&W Control Room IR WILD Server Any Authentic users Step 1 Step 2 Step 3 Step 3 Step 3 Typical Hurdles faced in Efficient Utilization of WILD Trains stopping, stalling, accelerating /decelerating, braking hard on instrumented track. GSM signals weak or erratic. Huge Power surges. Theft from site. Non-utilization of data trending features Improper understanding of the system.
- 5. 5 Site Selection Criteria (As per Tender) These criteria are drafted out based on the site conditions given in COFMOW’s WILD Specification no: COFMOW/IR/WILD/2006 and our recommendation. The system will be installed on straight and level track of minimum 250m length including approaches to the site. There should not be any permanent speed restriction at site of WILD system. The rail section shall be 60Kg/m with flat foot laid on Pre-Stressed Concrete (PSC) sleepers at 60 cm spacing with elastic fastenings viz. pandrol clips on rubber grooved sole and clean ballast cushion of 250/300 mm. The site will not be very close to any station or at the approach of a signal to avoid acceleration or braking over the instrumented rails. The Railways (DRM/Mechanical) shall ensure advance arrangement like sanction etc. to meet out recurring expenditure after one year of installation. The Railways shall ensure provision of reliable 230 V + 10% single phase electric power supply anywhere in 3 Km along track from the site of installation of the system before system installation is taken up by the firm. Additional Site Selection Criteria Site should have proper road approach for taking 13m instrumented rail near site through trailer. Site should have good GSM network connectivity for sending the reports (Preferably TATA INDICOMM.) Proper locality to safe guard the system from Theft / untoward activities. At least one side of the ground area is close to the level of Track and soil is strong and good for earthing. Preferred power connecting from OHE through Auxiliary transformer or nearby power resource from Railway infrastructure. Power taken from agriculture field will lead to lot of fluctuation and improper working. Installation Requirements In case of double line, system should be installed in a line where loaded trains traffic is more. Panel room should not be placed where area is marked as railways future expansion area. Old set of sleepers has to be replaced with new ones. Railways to provide 4 nos glued joint per system. Each glued joint to be fixed at each end of the two instrumented rails. Railways also to ensure the rails are welded on to the track. Railways to provide all permissions, line blocks to work on the site. All relevant departments to provide approval for the site, since once installation process begins, changing of exact site location (even by a few meters) would be extremely difficult.