The shortest path …

A long time ago in a country far, far away … The King heard about a new marvel of engineering … in England was invented a monstrous machine. It was moving by its own, magically propelled by coal fire and hot steam! Its speed was higher than the quickest eagle or the fastest horse! It…

The rectangular coordinates of the Bloss transition

(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…

A (Hallade) moment to remember

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…

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…