Jointed track breathing

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…

Joint Closure Temperature

Note: This article presents the Joint Closure Temperature (JCT) for free thermal expansion (FTE) track superstructure ; it is directly related and should be read in conjunction with the following articles: When can a rail be called long? presenting the definition of the concepts long rail and short rail, from thermal behaviour perspective. Track longitudinal resistance presenting the two…

Joint Resistance Force

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…

Chainage creep

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.…

Modern Railway Track

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…

Ich bin ein Berliner

I’ll be a Berliner, just for a day … joining the fellow railway engineers from around the world at InnoTrans 2016. InnoTrans is the largest rail industry event in the world, held every two years in Germany, at Messe Berlin – ExpoCenter City. Sub-divided into the five segments Railway Technology, Railway Infrastructure, Public Transport, Interiors and Tunnel…

White rails

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…

Evaluation of the track quality

Track measurement The importance  of  knowing  the  track  geometric  quality  arose  in  the  middle  of  20th  century,  when  European infrastructure managers developed their own track recording vehicles allowing a continuous measurement of track geometry and based on this, their own track geometry quality evaluation standards (EN 13848-6). Periodic track measurement is required to evaluate the…

Maglev Guideway Design

Maglev is a transport system that uses the magnetic levitation to move vehicles without contact to the guideway. The system uses magnetic forces for levitation, propulsion and guidance of the vehicle, thereby making practically negligible the friction forces and allowing very high speeds. The technological evolution is making this transportation system competitive and gaining consideration as a…

Track Longitudinal Resistance

There are two types of railway track superstructure from the point of view of the response to rail temperature variation: free thermal expansion (FTE) track superstructure which allows the rail to freely vary its length due to temperature variation. This superstructure does not provide reliable constant and easy to control and maintain track longitudinal resistance…