(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…
For the track realignment methods (Hallade or similar) the existing alignment is surveyed by measuring the outer rail offsets (versines) to overlapping chords. One such setup is drawn below: A’, B’, C’ are points on the outer rail of the track and for point B’ the versine B’D’ = vB ex is measured to the chord A’C’. We…
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…
There are three types of versines used for the track realignment and rectification methods (Radu, 2003): Measured (existing) versine – the versine measured with a real chord on the outer rail of the real existing track. This is the result of the versine (Hallade) survey and based on it are computed the track offsets (slues…
This is the presentation I gave to the Glasgow Section of the Permanent Way Institution: Track Quality Measurement and Inherent Design Standard Deviation Later note: Some fundamental things stated in this presentation need to be revised.
In the previous article, Jointed track breathing, was described for jointed track the complex activation phenomenon of the track resistance forces that oppose to rail thermal length variation. In the case of the jointed track this activation takes place on the entire length of the rail. As the rail length increases a greater temperature variation…
A railway track blog 