BS EN 13231-5:2018 pdf free.Railway applications – Track – Acceptance of works Procedures for rail reprofiling in plain line,
switches, crossings and expansion devices.
BS EN 13231-5 Thecomplexity ofvehicle-trackinteractiongenerates high stressesat therail-wheelcontact,the severity ofwhich is governed by local track characteristics,vehicle type and other operational conditions. Therepeated application of these stresses results in the development of fatigue cracks usually referred toas RCF manifested as head checks, gauge corner cracking, or squats. Although rail metallurgy offers akey mitigation measure against such fatigue degradation, there are no rail steels currently in use thatcould fully withstand the repeated application of such contact stresses.Furthermore the majority ofrails in track today, despite their adequate but lower fatigue resistance, have an appreciable residual life span, which makes it more economic to maintain them in an appropriate manner to extend their liferather than to change them.
Management of rail profile and condition is therefore a prerequisite for safe and cost effective operationof railways. Predictable work – at least in a medium time horizon – organized in a strategic way needsto be defined to extract the maximum benefit from existing technologies and to guide the industryfor future development. However, it is essential to ensure that the chosen approach provides enoughflexibility to adapt to changing situations in both senses: increased requirements for maintenancedue to higher loads and dynamic forces,reduced requirements for maintenance due to lower loads(improved vehicle characteristics) and better performing rails (reduced fatigue development).
The life expectancy of a rail is influenced by its interactions with the other parts of the train-tracksystem.The faster and more frequent train services, higher axle loads and new generations of vehicleswith greater primary yaw stiffness have significantly increased the critical track forces that promotemore rapid degradation of the rail (and wheel) leading to more frequent and costly maintenanceinterventions and even rail renewal. Significant research into rail metallurgy has resulted in thedevelopment of rail steels with much higher resistance to wear and RCF.Nevertheless rail maintenanceby reprofiling is an essential requirement for efficient and safe functioning of railway track. Thecombination of rail grade selection and maintenance strategy considering local track and trafficcharacteristics ensures effective control of any kind of rail surface defects.
Reprofiling strategy is a planned maintenance activity usually defined by the infrastructure maintainer.ln theory it is independent of available technologies,but in practice it is often influenced by theequipment that is easily accessible to or proposed by the contractors.work is programmed depending on damage having reached predetermined intervention thresholdssuch as corrugation depth, deviation from the transverse profile and depth of cracks.
Alternatively work is executed in cycles which are derived from experience and influenced byavailability of machines, track possession times and similar factors such as traffic, usually expressed inmega gross tonnes (MGT), months, seasons,etc. Often work is combined with other maintenanceactivities (e.g.after rail replacement, after tamping or when the line is closed for other work, etc.).BS EN 13231-5 pdf download.