This is the link to the second article I wrote together with Levente Nogy – “Rail thermal force calculations for jointed track” – and published in the Permanent Way Institution Journal – Vol 135 Part 2 (April 2017). Article 2
Rail steel has a considerably higher carbon content (0.7-0.8%), and hence is more brittle than mild steel. A variety of stress concentrating defects in rails, combined with the alternating loads from the passage of traffic, can produce slowly propagating fatigue crack. When this crack attains a critical size it causes an almost instantaneous brittle fracture…
(prelude to a new PWI Journal article) A stress transition zone is any section of continuous welded rails (CWR) where the thermal force is variable, the longitudinal resistance (p) is active and rail movement occurs due to rail temperature variations. The most common (and well known) location of the stress transition zone is at the…
(Quickly but nostalgically written, remembering the good old days when Taylor was not yet known as the name of a beautiful singer but as the laborious math trick used to solve rather painful Mathematical Analysis problems …) The deflection angle (θ) of the Bloss transition is: The rectangular equations (x and y) of the curve are…
ΔG = αLΔT°. Free expansion For a free thermal expansion jointed track the rails expand and contract freely and the track components do not provide any resistance to oppose this rail length variation. The joint gap varies linearly relative to the rail temperature. The figure below presents the joint gap variation for a jointed track formed…
Perhaps I’m splitting hairs here, but it is a fair question to ask: When a 20 m rail is 20 m long? Please, have your say and feel free to comment below, after voting! And this is not a trap question like “Which weighs more: 1 kg of steel rail or 1 kg of feathers?”. Later edit: By…
The thermal behaviour of the jointed track can be analysed throughout a full annual temperature variation and used to define the joint expansion gap variations. The joint gap varies between the maximum value and zero and this is related to the way the rails are allowed by the track resistance forces to contract and expand in…
This is the presentation I gave to the West of England Section of the Permanent Way Institution:
I feel very honoured and proud to see the article “An introduction to rail thermal force calculations” I wrote with my friend, Levente Nogy, published and featured on the front cover of the Journal of the Permanent Way Institution.
Joint resistance The normal rail joints are designed to allow the rail length variation due to temperature. To do this the joints have a well-defined maximum gap and a set of installation parameters to provide an optimum behaviour at temperature variation and a good maintenance regime. Any modern rail joint has a standard bolt tightening torque…
A railway track blog 