Significance of jointed track parameter variation

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…

Checking the versine survey precision

A field measurement of any kind is never exact and intrinsically contains errors (NJDoT Survey Manual – 2014). For track topographical measurements some of these errors are known and eliminated by applying appropriate corrections and compensations. Even after all known errors are eliminated however, a site measurement will still be in error by some unknown value. To minimise the…

Types of versines used for track realignment methods

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…

Track Realignment and Rectification

The running of the trains over the railway track is inducing vertical and lateral forces that, in time, are affecting the track alignment, changing incrementally the installed track and causing track irregularities.  On curved track this deterioration process is more significant due to the additional effect of the lateral (centrifugal) acceleration. When the irregularities become…

Mauzin (Hallade) track measurement car

The measurement and analysis of track geometry is carried out regularly by all the railway infrastructure administrators in order to obtain data from which the track quality is established and the maintenance can be scheduled (Cope – 1993). Historically, the use of track inspection cars can be traced back to the early 1920’s in France…

Flange tip lift crossing

The crossing is the track arrangement which ensures the intersection of two opposite running edges of a turnout or diamond crossing. It usually has one crossing vee and two wing rails (BS EN 13232-1:2003). The crossing, in the common setup, has a gap section to allow the passage of the wheel flange on both directions. The safe…

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…