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…
Rail breathing Normally on the railway track the rail is fixed through a set of superstructure elements (fastenings, sleepers, ballast) that opposes the rail tendency to expand or contract due to temperature variations. This fixation is achieved through friction forces and once the rail axial forces are above these friction forces, the rail will start…
All the railway track fishplates for mechanical joints are designed to provide a gap to the rail web. This gap, together with the wedge shape of the fishplate section ensure, by tightening the joint bolts, the correct alignment of the rail head between the two jointed rails. The bolt tightening torque is developing in the bolt a…
When designing multiple line alignments – in railway stations or plain line sections – there will be a creep of the alignment stationing due to the length difference between the alignments. This stationing (or chainage) creep becomes relevant when adjacent alignments have to be kept at the same level or with a well-defined elevation difference.…
Motto: Tolle lege! Perhaps the best and most complete technical book about track is “Modern Railway Track” written by Dr Coenraad Esveld, Professor of Railway Engineering at Delft University of Technology. A detailed Table of Contents of the second edition can be found here together with a brief selection of the book. The second edition, written…
When exposed to temperature variations, the rail tends to vary its length. If this tendency would be freely allowed, for a temperature variation Δt° the rail length L will vary by ΔL. This length variation is ΔL = αLΔt°. If, on the other hand, the expansion is not permitted in any way, and both ends of…
INTRODUCTION In transportation infrastructure design the route is defined based on its axis (centreline) – the alignment model. This simplified abstract model is designed in such a way to clearly define the principle course of the infrastructure project. For most of the transportation means the infrastructure alignment design is split into two main two-dimensional complex…
A railway track blog 