Motto: Tolle lege. Most of the railway track design standards around the world are presenting the particular issue of the reverse transition. All these standards are insisting on keeping a constant rate of change of curvature – a constant A. By doing this in fact the design will include a single continuous transition between the two opposite circular…
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…
After the post about the limits of vertical acceleration, and even before, I was asked what was the original curve used to connect vertical gradients. What was first, the circle or the “egg”- the parabolic curve? The expected answer was “the circular curve” because, presumably, a circle can be drawn easier than a parabola… “How…
An anecdote: Track geometry exam, somewhere at a Civil Engineering University. One of the exam subjects is realignment methods and types of versines. This important subject was covered during the track course hours but also in four seminars and in a realignment project homework – so it was supposed to be an easy one … After checking the…
The theory of vertical movement. The parabolic projectile motion An object thrown in the air, near the earth’s surface, moves along a parabolic path under the action of gravity only. The only force of significance that acts on the object is gravity, which acts downward to cause a downward acceleration. Because of the object’s inertia, no external horizontal force is needed…
Another classic book it sure is “British Railway Track Design, Construction and Maintenance”, edited by Geoffrey H Cope and having around 40 contributors for writing the 30 chapters of this essential track compendium. Its last six edition was published in 1993 by The Permanent Way Institution. Presenting the essential principles but also the British specifics…
The slides of the presentation I gave in November at the West of England section meeting of the Permanent Way Institution: The main topics presented: – Cant parameters definition. The origin of the 11.82 (UK) cant constant. Ways of applying cant. – Track geometry recording. Track Quality Standard deviation. Inherent standard deviation. Quality bands…
When it comes to Railway track engineering literature, there are a few books we can consider “classic”. Even old, some very old, these books still have significant railway engineering value and can be always a good reference both for young and inexperienced engineers as for the ones that already have robust railway track experience and…
The good old times Since the early beginnings of the railway, the track engineers were aware of the centrifugal forces influence to the train riding when passing through a curved section of track. To compensate this influence, the track was inclined laterally by creating a positive level difference between the outer and inner rails of a…
In transportation engineering there is the following signage convention for curves in horizontal alignment design: a right hand curve is considered positive a left hand curve is considered negative This convention is considered relative to the stationing direction of that alignment. This signage convention is established in the following way (see the figure above):
