Railroad Wheel and Brake Failures and Detection

1. Matzan Reliability Solutions
2187 North Washington St., Rochester, NY 14625
http://www.matzanreliability.com ematzan1@rochester.rr.com
Acoustical Wheel Defect Detection
Railroad Car Wheel Related Problems;
• Prevention
• Detection
For more information contact:
Eugene Matzan
ematzan1@rochester.rr.com
Phone 585 387 8921

2. Dragging Brakes Have Devastating Consequences: When Brakes are applied they
can be fully engaged, partially engage, or no brake at all. This leads to wheel and bearing
failure and can result in derailment.
Observations: The assumption is that the 12 PSI air pressure application is constant.
Signal analysis and infrared conformation shows that 60% of the brakes do 90% of the
stopping. Two cars, (5%) on a 40 car train do not come on at all.
These are Infrared images of a wheels with the brake applied. The farther up the red
scale the hotter the wheel and the more brake pressure is indicated.
Fig 1 Fig 2 Fig 3

3. Dragging Brakes have Consequences:
What Causes Wheels & Bearings to Fail?

4. Why Equipment Fails
ASLE Bearing Workshop M.I.T. Study
Rabinowicz, 1981
Equipment Fails
Because
Obsolete
15%
Surface Degrade
70%
Corrosion
20%
Caused by
Water in oil, degraded oil,
Process contamination,
Coolant, condensation…
Wear
50%
Fatigue Wear
Damage resulting from
Micro-cracks loading
Caused by
Misalignment, imbalance,
Improper fit / assembly,
Secondary damage
Abrasive Wear
Damage resulting from
Abrasive particles
between
Two moving surfaces
Caused by
Abrasive particles in oil,
Dirt, secondary wear,
Process contamination
Adhesive Wear
Damage resulting from
Metal surfaces dragging
Over each other
Caused by
Inadequate lubrication
Low visc, no oil, high temp,
Excess load, slow speed..
Accident
15%

5. The typical grease used in these railroad car wheel bearings is Lithium
based grease with a mineral base oil. The recommended temperature
range is 180°F. The chart below shows the temperature range of a nominal
Lithium based grease.
Bearing Temperature °F
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 25°F increase in temperature above
160°F, the lubricant life is more than halved and there is a negative effect on
bearing life. Any mineral oil operating at a temperature above 190°F will have a
greatly diminished life. In no case should bearing temperature ever exceed the
maximum rating of either the bearing or the lubricant.

6. SKF high load, extreme pressure (EP) bearing grease
LGEP 2
LGEP 2 is mineral oil based lithium soap thickened grease with
extreme pressure additives. This grease provides good lubrication in
operating temperatures ranging from
–20 °C (–4 °F) up to 110 °C (230 °F).

7. Premium Rail Grease
Timken Premium Railroad Grease has an operating temperature range of
-40°C to +121°C (-40°F to +250°F) once in the application.
CAUTION: Follow equipment manufacturer’s recommendations concerning
lubrication frequencies. Failure to follow correct lubrication practices can
result in premature equipment failure.
Viscosity @ 100°C, ASTM D 445, Centistokes 15.5
Viscosity @ 40°C, ASTM D 445, Centistokes 163
Viscosity Index 96
Base Fluid Properties:

8. Adhesive Wear

9. Hot Box Detectors are Limited
•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.
Wayside Ultrasonic Systems are Limited
•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 Microphones along the track.

10. New Technology
Track Isolated Ultrasonic System
• Detects and Locates Problems before the train leaves the yard
• Mechanical Brakes engaged
• Malfunctioning Air Valve
• Broken Wheel
• Wheel Flats
• Wheel Hunting

11. Theory of Operation:
Metal surfaces will vibrate if excited by a force, (gong ringing a bell), or friction, (sound made from
squealing brakes). The Amplitude or size of these sound waves is generally proportional to the
force applied. Hence steel rails generate a sound at the wheel – rail interface caused by the normal
vibration in the wheel. Dragging brakes, wheel flats, and defective wheel bearings will generate a
higher level of vibration than a “Normal” wheel because of the greater amplitude of force
generated by these conditions.
A drawback or hindrance to the analysis of these signals is that signals from different wheels
interfere and mix with each other and make identifying a faulty wheel difficult to pin down. In fact,
a train can be “heard” or monitored a ½ mile away under normal conditions.
In our approach to resolving the problem of cross talk between wheels we have developed and
patented a technique that isolates the sound generated from each wheel so that individual wheels
can be analyzed. The methodology is to clamp rubber bumpers to the rail in a sandwich type of
arrangement on either side of a transducer. The transducer acts as a microphone and records the
sound generated by the wheel. The rubber composite material acts as an acoustical insulator that
absorbs the vibration on either side of the transducer limiting the sound waves to only those
generated by the wheel as it passes over the transducer.
11

12. The system is composed of Ultrasonic Transducers mounted to the track. Sections of
Railseal are used to isolate the ultrasonic vibrations, Wheel Sensors that detect the
location of the wheel, and a Control Panel that houses amplifiers and electronics.
Equipment Layout
The system installs in hours, can detect several wheel failures; stuck brakes, air
leaks, brakes that fail to actuate when applied, wheel flats, wheel spalling, and
truck warp are some of the inspection capabilities of this equipment.

13. Method of Isolation
Sections of Rubber Rail Seal are sandwiched in the web of the track and held in place by
clamps inserted under the rail or to the railroad tie. The ultrasonic transducer is located
between the dampened sections of rail.
Urethane Rubber isolators
Ultrasonic Transducer and Rail Clamp
This unit clamps to the track at the base of the track
and fits into the track web leaving only a small portion
of the transducer exposed. No electrical contact to
the track is present and this has been approved and
tested at TTCI and other railroads.