Visual assessment of longitudinal wheel timbers and assessing the feasibility of extending wheel timber service life in the UK railway network
J R Williams
Timber has been a versatile building material for centuries and during the start of the Railway Age in the nineteenth century it was in considerable demand for use in the railway network, particularly bridge building. Timber is still in service and widely used throughout the UK railway network. The resilience and favourable strength to weight ratio and its relative ease of fabrication make it an attractive material for use in the network. Longitudinal wheel timbers are used extensively to carry track in situations where it is desirable to reduce the weight of bridges and in locations where the depth of the structure prevents the use of ballasted track. Most wheel timbers in the UK comprise creosoted Douglas fir, southern pine or European redwood and to a lesser extent, naturally durable tropical hardwoods. Wheel timbers installed post-2003 tend to comprise softwoods treated with aqueous borne ‘copper/organic’ formulations. Concerns about the effects of fungal decay and non-standardised inspection regimes are problematic. Managing the network is complex and imposes high and often conflicting demands on infrastructure asset managers. Effective asset management within a safety critical sector is an essential discipline and it is the variable nature of timber that presents significant management challenges. This paper summarises a possible strategy to improve the examination and assessment of wheel timbers and assesses the feasibility of extending service life of wheel timbers exhibiting signs of localised decay. This approach may deliver more effective asset management of timber assets.
Keywords: timber, railway, asset management, decay, service life