A small device can make great use to all the world’s railways. It is the aim when a new portable tester, which, when you fix it directly on the rails, can measure the wear and friction with great resemblance to reality at all types of railway tracks, and thereby reduces costs of maintenance. The device is designed for Railway Research Center (JVTC), at Luleå University of Technology.
– This is going to advance research and reduce the cost of rail maintenance. The gain is the ability to calculate the maintenance requirements with considerably greater accuracy than before, for decades to come, says Jan Lundberg, a professor of Operation and Maintenance Engineering at Luleå University of Technology, who works at the Railway Technology Centre (JVTC).
Professor Jan Lundberg at Luleå University of Technology, shows his measuring instrument.
Corresponds fully loaded ore train
He calls it a “little sweetie” but appearances are deceptive. Although the friction and wear tester looks so insignificant, it has the ability to match the weight of a fully loaded ore train when the wear and friction should be measured on the railway tracks in operation. The tester is made of brass, aluminum and stainless steel and can be attached to all types of rail how even worn rails are. It has eight wheels which are adjusted to be entitled to that particular rail that is current for testing of all its wear and asymmetry.
Like a Russian doll, convicted of different weights into the tester, depending on the type of train the device should imagine such as passenger train (with or without passengers), freight train or a fully loaded ore train in full throttle as thunder past. It is an extremely small ball (just 5 mm) in the middle of the tester that will be with all this his weight against the rail, which allows the small sample’s weight to correspond to, even heavy freight trains. Therefore, the device only needs to be driven 5 cm on a rail at a few different sites to get a realistic measurements.
Consideration of dirt and snow on the tracks
The tester provides friction (friction) and abrasion (wear constants) with great reality for the railway in practice, without parallel today.
– The incorrect measurements supplied with current methods can make the cost of maintenance of the railway that is predicted, to be much more expensive or less expensive than in reality. Out in the field the rail keeps maybe twenty years although the current methods can give false results forecasts on sustainability for just five years, says Jan Lundberg
Precision without parallel in the world
A major challenge for today’s infrastructure, the owner of the railway system, is to reduce costs and streamline maintenance of track components. It is not only the weight and pressure of the train on the rails that are the problem when it comes to wear and tear, but also the friction of the wheels that wear the rails. Jan Lundberg research team has made unique tests with real fully loaded ore train in full throttle running on railway tracks in Lapland. The tests show that the calculations done with today’s equipment when it comes to friction on the rails and which is the basis for the current cost of maintenance, is grossly misleading.
– They can be up to 220 percent wrong. Our unit has a precision unparalleled in the world today since it brings the importance of rain, snow and lubricants available on the rail outside. At present, scientists are referring to very costly laboratory tests with so-called disk-disk devices because they can not take into account the actual ambient conditions prevailing in the real world of the railway, delivering totally unrealistic measurements and thus useless metrics for predicting rail wear and friction, says Jan Lundberg.
The little friction and wear tester has patent protected (two patent applications) and will perform further tests outdoors in, 2016.
Weight: About 9 kg
Width: 0.2 m
Length: 0.2 m
Material: Stainless steel, brass and aluminum
Types of rail: All existing railprofile worldwide
Press Contact: Variable 5-2000 MPa through the variety of weights and radius
Contact ball diameter: Variable 3-10 mm
Calculation of contact pressure: Hertz contact pressure theory
Sliding speed: Variable 0-0.5 m / s
Power source: electric motor with frequency control
Materials for wear testing: all kinds of metals, polymers, etc.
Measurement of wear volume: Microscopy
Showdown: Portable oscilloscopes
Author: Katarina Karlsson on 24th May 2016