Sean Livingston explores how vital rubber components overcome changes in temperature
For many aspects of the railways, performance goes hand-in-hand with the operational environment. Temperature is one vital aspect of this, affecting how particular components function. Rail tracks, for instance, expand in the heat, lengthening by around one inch per mile for every 1°C increase above 27°C, directly impacting how vehicles are able to run. Similarly, rubber – a vital component within the industry – is affected by changes in temperature. So whether it’s the high heats of Dubai’s underground or the icy cold extremes of Siberia, it’s crucial to take the operating environment into consideration before the specification of any parts.
Rubber is a very durable material. It’s this quality – amongst others – which makes it hard to replicate on the railways, especially in anti-vibration components. But when temperature is taken into account, what seem like small changes generally, can change the core characteristics of rubber. If the operating temperature changes by 10°C, the stiffness of the product changes by 1%, triggering significant changes in performance.
For rubber components employed in railway vehicles, precise dimensions and compounds are critical to their continued performance. Let’s look at anti-vibration mounts as an example, which are typically installed to isolate vibration and noise, protecting assets which are crucial to the reliable functioning of vehicles. With a greater deflection rate than that of steel, rubber is able to stretch considerably more before becoming deformed, so it can cope with greater strains and last longer. Its high load bearing capacity and potential to be chemically manipulated to provide a broad range of characteristics also mean it can handle the harsh conditions of the railways, customised for a whole range of applications.
To ensure these benefits are consistently felt, having an understanding of the operational environment allows for a suitable rubber formulation to be created, bespoke to the challenges the mount will have to endure. With even slight changes in temperature affecting the rubber’s tolerance and its ability to perform at the required level, testing is a vital part of the development process.
Once a particular batch of rubber is produced, unique to the particular application it is specified for including variances in temperature, our fatigue tests ensure the product is able to cope, even at the extremes. So even when the heat is on, rubber mounts still perform to their required levels, helping rail vehicles to sustain even the harshest of environment.
As well as Trelleborg’s portfolio of more than 300 rubber formulations – which enable us to select the right performance characteristics for every application – we also 100% test every chevron, every airspring and every hourglass mount that leaves our factory, as an additional guarantee.
Discover more about our solutions to some of the biggest challenges on the railways here: http://www.trelleborg.com/en/anti-vibration-solutions/your–industry/rail–and–mass–transit