TRACK TECHNOLOGY
Accurate and reliable wheel measuring
Antti Moisio of Tamtron discusses wheel defects – a common problem in trains – and what can be done to avoid them. S
everal factors can cause undesirably high forces on rails, including fl at wheels or
other kinds of de-formatted wheels, wheelsets not following the track precisely, and overloads or uneven loading in wagons.
Wheel defects are detrimental to trains and tracks. Flat wheels damage the railway tracks and may overheat the bearings, which causes axle damage and even detached wheels. Worn-out and damaged bearings can also cause various types of wheel defects.
These are some of the different kinds of wheel defects:
1) Wheel fl ats: normally caused by blocked brakes
2) Material faults or bad reparation (welding): parts of material detached from wheels
3) Rolling contact fatigue defects: wheel spalling and shelling. Though all these defects and mechanisms of their formation are generally known, however, there are many particularities in the defect’s appearance
4) Wheel out of round / asymmetrical wheel: well-known from different kinds of trains, wheel radius variation 0.2-3.0 mm, different shapes of radius variation, fi rst occurrence is unpredictable
Scalex Wild monitors the forces between wheels and rails, thus discovering fl at wheels or other wheel defects that can damage rolling stock or track. If the pre-set alarm limits are exceeded, the system immediately launches an
180 | rail technology magazine Apr/May 14
alarm and indicates precisely which wagon(s) and wheel(s) triggered the alarm.
After the alarm, the traffi c controller can take necessary measures to stop the train or to reduce its speed in order to minimise the risks and damage.
Scalex Wild has two unique features: measurement reliability and very low speed measurement. The system measures each wagon wheel through two complete rounds, which ensures that the measuring is both accurate and reliable.
The other feature is its capability to measure accurately at low speeds, starting from 10km/h (6mph). Thus Scalex Wild can be used in industrial areas and other areas where similar systems have not been previously functional.
Besides discovering wheel defects, Scalex Wild also weighs trains’ wheels, axles, bogies and wagons automatically up to speeds of 250km/h (155mph). Overloads and uneven loading are measured, with alarm limits for both lateral and longitudinal loads.
Installation of Scalex Wild is easy. The equipment is assembled and tested at the workshop. At the site, 10 metres (33 feet) of the existing track is replaced by the Wild module.
The system can start operation immediately after installation: there is no need for a main-frame or software from the customer’s side. We offer a ready-to-use server application, accessible via the internet.
The Finnish Transport Agency – happy with the investment
After testing equipment from different manufacturers, the Finnish Transport Agency (Liikennevirasto) decided to invest in Tamtron System’s wheel impact load detectors. The next installation will take place in late May, after which the total number of Wild systems in Finland will be 10.
Senior offi cer at the agency, Seppo Mäkitupa, said: “Dynamic wheel forces will be monitored with the new system. The measuring is automated and its repeatability is improved. Until now wheel problems have been traced by the ear, by various instruments, visually or at the workshops.”
Increasing interest in the east
Railway traffi c between Finland and Russia is very busy. In addition to Russian freight trains, there are passenger train connections from Helsinki to St Petersburg and Moscow. This, of course, increases co- operation between the Finnish and the Russian railway authorities.
The fi rst Wild system has already been installed for RZD (Russian Railways) in November near Moscow and the next systems are already scheduled for 2014.
FOR MORE INFORMATION
T: +358 400 211560 E:
antti.moisio@
tamtron.fi W:
www.tamtrongroup.com/en/products/ scalex-wild
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