INTRO: By detecting alignment and tracking faults as a train passes, wheelsets suffering excessive wear caused by bogie defects can be identified before their economic life is compromised
BYLINE: Denis D’Aoust and Grigory Izbinsky*
BYLINE: * Denis D’Aoust is Chief Engineer, and Grigory Izbinsky is President, Wayside Inspection Devices Inc
REPROFILING or replacing worn wheelsets absorbs a significant proportion of rolling stock maintenance costs. Consequently, much effort has been devoted to ways of extending wheelset life. Established methods - none of them cheap - include improvements in wheel and rail materials, lubrication, asymmetric rail profile grinding, and the introduction of premium bogie designs.
A more efficient approach is to detect geometric faults in the alignment and tracking of wheelsets in a bogie which cause premature wear, so that corrective action can be taken before costly wheelset maintenance or replacement is needed.
Misaligned wheelsets are a sure sign of trouble. It is now possible to measure the angle of attack of individual wheelsets in real time using wayside inspection devices. Angle-of-attack inspection stations have been developed primarily for heavy haul railways, but they also have a use on passenger railways. AAIS can also determine whether the two wheelsets in a bogie are tracking correctly.
Failure to detect and rectify bogies with misaligned wheelsets not only increases the wheelset removal rate; it also compromises other measures taken to maximise wheelset life such as matching wheel tread and rail profiles. Bogies that have misaligned wheelsets will wear out their wheels unevenly and at an accelerated rate, while other bogie components will suffer accelerated wear and tear.
Misaligned wheelsets are also responsible for increased fuel consumption and accelerated track deterioration. A tool that reliably identifies bogies with misaligned wheelsets, allowing operators to make timely repairs, can typically: