1 Railroad Car Wheel Defects 03Presentation Transcript
Railroad Car Wheel Related Problems; It is Far Better to Prevent Them Than to Fix Them Failed Wheel Bearings, Wheel Flats, and Worn Track are the Effects not the Cause For more information contact: Eugene Matzan [email_address] Phone 585 387 8921 A Reliability Centered Maintenance Presentation
On Average, 3 Truck Sets per Train Have Dragging Brake Sets. This causes damage to wheels, wheel bearings, and track Eugene Matzan http://www.matzan.com [email_address] Phone 1 585 387 8921
These images are infrared images taken of a moving freight train. The image on the left is a normal car with the wheel bearings showing a slight buildup in temperature. The image on the right is a dragging brake causing the entire wheel to heat because of the additional friction. Eugene Matzan http://www.matzan.com [email_address] Phone 1 585 387 8921
The typical grease used in these railroad car wheel bearings is Lithium based grease. The recommended temperature range is 70°C over ambient temperature. The chart below shows the temperature range of a nominal Lithium based grease. Figure 1 shows the thermal range of a typical rolling element bearing used in Railcars. The green zone represents the sweet spot for bearing and lubrication temperature; operating in the yellow zone reduces lubricant and bearing life; and if your bearings are in the red zone, expect both the bearing and the lubricant to be destroyed rapidly. For every 15°C increase in temperature above 70°C, the lubricant life is more than halved and there is a negative effect on bearing life. Any mineral oil operating at a temperature above 80°C or 90°C will have a greatly diminished life. In no case should bearing temperature ever exceed the maximum rating of either the bearing or the lubricant.
This buildup of heat causes rapid lubricant deterioration resulting in bearing damage.
Because Railroad wheels and bearings are slow moving, they may run on bad bearings for a long time before Catastrophic Failure, this dose not mean that the wheels are not damaged.
Even though the bearings do not totally seize , the increased rolling friction and continuing brake drag:
Increased Fuel Consumption
Increased Track Wear
Damaged Wheel Bearings
Leading to Catastrophic Failure and Train Derailments
Heat is a very late indicator of bearing problems. By the time they are hot enough to detect damage has hit an irreversible stage.
The inner bearings can not be scanned at all reducing the Hot Box detector to an effectiveness of 50%
Reflected light, load, speed, weather, and distance all affect wheel and bearing temperature.
Weigh side Ultrasonic Systems are a Bad Choice
The inner bearings can not be scanned at all reducing the Sonic System by an effectiveness of 50%
Wind, weather, load, background noise and speed all affect the sound signal using speakers along the track.
Industry has used modern technology to detect bearing problems, there by reducing failure and downtime. In the Railroad Industry Failure can be Catastrophic, yet these Predictive Maintenance Systems do not render themselves as an alternative without modification. Because trains are not stationary conventional methods of using probes or sensors are not practical. An effort was made by the Transportation Research Board of the National Research Council, (“Signal Transmissibility of Railcar Bearing Vibration” HSR-56 study) to insert sensors into the track and monitor wheels as they passed over. It met with only minimal results although the stationary lab tests proved quite successful. Because the rails are a very good conductor of ultrasonic frequencies background noise made detection difficult. The Solution is to Segment A Track Section So that Only One Wheel at a Time is in Contact with the Section.
WR1 WR2 P1 Piezoelectric Sensor WR 3 WR4 WL1 WL2 P2 Piezoelectric Sensor WL 3 WL4 An acoustically isolate track section is used to reduce and isolate noise and vibration interference from the rest of the train. This is accomplished by segmenting and inserting a 55” in length of rail and epoxy splicing the section at a fabrication facility in a controlled environment. This “glue” is approved for joints in rails and meets all FRA requirements. This arrangement is assembled in a Precast Concrete section Which Isolates and supports the track. Ultrasonic Sensors are mounted to the isolated section of track.
U.S. Cl. 246 — 169S [246/169 R] A system for automatic detection of defects in railroad wheels, a system that is stationary and is installed in extended intervals in the rails uses stationary acoustical/vibration sensors installed at intervals in the rails. Rail segments associated with the detectors are acoustically isolated. The sensors acquire the sounds and vibrations generated by the wheels rolling over the rails. Signal analyzers identify rail defects from intensity vs., frequency distributions of acoustical spectra. Such spectra reflect the condition of the wheels and change their intensity vs. frequency distributions when the wheels pass the sensors installed in the rails. The acquired information on the condition of the wheels is transmitted to a central location. Any defective wheel is identified and marked for repair or replacement. US 7,213,789 B1 SYSTEM FOR DETECTION OF DEFECTS IN RAILROAD CAR WHEELS Eugene Matzan, 2187 N. Washington St., Rochester, N.Y. 14625 (US) Filed on Feb. 06, 2004, as Appl. No. 10/772,535. Claims priority of provisional application 60/466241, filed on Apr. 29, 2003. Int. Cl. B61K 9/00 (2006.01
Benefits of Implementing This Technology
Fuel saving from reducing friction and drag
Reduced Track wear
Reduced derailments associated with wheel failures
Reduced Maintenance on wheels
Scheduled repairs in the yard
Knowing the exact weight of each car
Railroads for years had a simple solution to increased friction, add another engine , but in today’s emphasis on Fuel Economy, Safety, and Reliability it may be time to investigate this new alternative.