Evaluation of technical vs economic decisions in rail grinding
Rail is a significant capital asset for railway companies. It contributes more than half of the capital assets of railway infrastructure. Recent rail inspection data using Ultrasonic rail testing has shown increasing number of rail defects, failures and causing disruptions to rail services. This cost can be further increased when the track quality is poor. In recent years, railroads have been purchasing over 500,000 tons of rails per year at an estimated total cost of US $1.25 billion for replacement of worn out and degraded rails. Rail grinding is considered as viable means in reducing the impacts of rail defects and failures. Rail grinding can result in improved curving performance (wheel/rail interaction) and prevents crack initiation and propagation of surface cracks due to RCF. This paper focuses on analysis of rail degradation process and development of mathematical model considering technical and economic decisions in rail grinding to rail infrastructure owners.
TO GRIND OR NOT TO GRIND
SUBTITLE: RECENT FINDINGS SUGGEST THAT RAIL GRINDING MAY BE COUNTER- PRODUCTIVE, BUT SOME CHIEF ENGINEERS, RELYING ON THEIR OWN POSITIVE EXPERIENCEWITH GRINDING, AREN'T CONVINCED.
Wheel-rail contact mechanics at full scale on the test stand
This paper reports on the measured wheel-rail creep force characteristics and the mechanism of corrugation formation by using a full-scale bogie on a test stand. The measured creep characteristics agree well with the calculated values based on Kalker's linear theory. The relationship between creep characteristics and contact position is also discussed. The results show that a small change in wheelset lateral displacement may lead to a great change in creep characteristics. Mathematical models are developed in order to explain the mechanism of corrugation development. Simulation results agree well with practical phenomena. From the simulation results we find that the creep force characteristics and the vertical oscillation system have great influence on the formation mechanism of rail head corrugation.