INTRO: Significant improvements in operating safety and reduced rolling stock maintenance costs have followed the introduction of automated train health monitoring systems on Australia’s Mount Newman iron ore line
BYLINE: Janusz Dudek
Principal EngineerAdvanced Technical Research Organisation
PILBARA heavy-haul railway operator BHP Iron Ore has introduced a whole train condition monitoring system on its former Mount Newman line running inland from Port Hedland. Better known as the Automatic Car Examiner Station, the train health condition monitoring system is currently being used to inspect more than 2 000 wagons per day. Using video and acoustic image processing, the technology was originally developed for space research, but was adapted for rail by Western Australian firm Advanced Technical Research Organisation.
ACES comprises four principal units, or ’stations’. The supervisor’s console (station 4) is located in BHP’s air-conditioned office situated in the Ore Car Repair Shop. The other three stations, covering Train Departure & Arrival, Car Dumper 1, and Car Dumper 2, are located 7 km away from the supervisor’s console. They use 22 CCTV cameras, 18 proximity sensors, microphones, frame grabbers, and other components to carry out the whole condition monitoring process on moving trains. The ATRO-developed software runs on seven 6X86 computers networked together.
The train health monitoring system installed at Port Hedland is the first automatic system in the world to monitor so many wagon components in motion simultaneously. Not only does it outdo the scope of a traditional car examiner, it adds a new dimension to train heath condition monitoring, setting new standards for the 21st century.
Brakes and flats
At the Departure & Arrival Station (No 1) video cameras on both sides of the track monitor whether any handbrakes have been left applied on the departing train. As each train usually consists of 240 wagons, manual inspection by a car examiner has proved very difficult, especially when the train is moving at a speed of 30 to 50 km/h in the extreme conditions of the Pilbara, where daytime temperatures can exceed 40°C. With ACES the train inspection is carried out much more efficiently using one 6X86 microprocessor, a frame grabber and two cameras.
If the processing software detects that any handbrakes are still applied, the wagon’s images are automatically transferred by modem to the supervisor’s console. A synthesised spoken warning message draws the supervisor’s attention to the fault indication, and to the image of the handbrake displayed on the screen for verification (Fig 1, above right). The supervisor can then call the driver by radio to stop the train.
Departing and arriving trains also have their wheels acoustically examined by the same computer that collects and analyses the handbrake images. Two microphones located on both sides of the track collect the audio signal from the passing train, digitise it and save it to the computer hard drive. A Car Examiner’s perception of a wheel flat or a bearing noise can be very subjective and non-quantitative. It depends on the time of day, background noise level and the fatigue level of the person. A computer does not suffer from these factors. A Fast Fourier Transform (FFT) algorithm is used to detect any wheel flats or bearing noise. This information and the selected part of the sound files can then be transferred to the supervisor’s console. The threshold at which the system picks up a fault has been set for the average level as used by the car examiners.
The two stations at Car Dumper 1 and Car Dumper 2 are identical. Their job is to inspect all the remaining ore car components which are not inspected at the Departure & Arrival station. At present 10 different items are being inspected at the Car Dumper stations: