L.B. Foster Rail Technologies (Canada)

This paper presents an assessment of newly-developed conductive adhesion materials (Products A-E) in comparison to standard rail sand used in Britain. Current rail sand is an insulating material which can affect track circuits; newly-developed conductive materials could reduce the risk of this and allow for more material to be applied to further mitigate against low adhesion. The particles were characterised to determine their densities, and size and shape distributions. Bulk behaviour was assessed through three characteristics: angle of repose, bulk shear strength, and particle breakage index. Materials were then assessed using a high pressure torsion approach to measure their effects on adhesion and electrical resistance in dry, wet, and leaf contaminated conditions. It was found that all products produced better or equivalent conductivity compared to the currently used GB rail sand and that Product D and Product E should be considered for future field testing.

ABSTRACT A novel tribo-testing method using a pin-on-plate tribometer was developed to test and visualize the coefficient of friction over surfaces with oxides present to examine low adhesion issues. Tribo-test data was recorded each pass over test surfaces showing how friction changes with mechanical action. Trackside environmental monitoring and railhead swabbing was performed to investigate the physical and chemical environment of the railhead. Iron oxides were both synthesized on and deposited on rail steel substrates to simulate ‘wet-rail’ conditions. Powdered oxide layers of magnetite, haematite, goethite and lepidocrocite were deposited on rail steel substrates to investigate individual oxides. Composition was analysed using X-ray diffraction and scanning electron microscopy before testing. Magnetite, Haematite and Lepidocrocite were formed when water alone was applied to the surfaces. Low friction was observed on oxidized sample surfaces only outside high roughness, oxide pitted, areas, but these conditions were shown to be difficult to achieve and transient.

Canadian Pacific (CP) has taken a systems approach to minimizing the stress state and maximizing velocity in high-tonnage, heavy haul western Canada mainline operations. Recognizing the interaction between wheel-rail contact mechanics, train handling, and track geometry, CP has tested and implemented a number of advanced technologies that leverage current knowledge, systems, products, and equipment in each of these areas. This includes implementation of distributed locomotive power configurations based on sophisticated track/train interaction modelling, as well as the state-of-the-art top of rail and gauge face friction control. Together, these technologies have resulted in reductions in damaging lateral forces, rail wear, and fastening system fatigue, as well as increases in velocity and network capacity. This article presents the theory, implementation, and verification of distributed power, fine tuning curve superelevation and friction control technologies within the practical operating conditions of British Columbia.

Problems associated with internal stresses (otherwise referred to as residual stresses) introduced during the making of rails have been evident for the past decade. The fact that few derailments have been attributed to it stems more from the lack of understanding of the phenomenon than from its absence in the causality of derailments. Although a number of articles have been written on the subject of residual stress, the main area of concern, for obvious reasons, has been the heat-affected zones such as within the rail head and at weld locations.