A different kind of article … Antescript Several times, in the last ten years, I started to write articles with this title. The only draft I kept is so convoluted and confusing that I might even decide to publish it. I have a few answers to this question. There is one I hesitate to put…
On the shoulders of CWR giants In 1994 UIC (the International Union of Railways) and ERRI (the European Railway Research Institute) set up a committee of specialists – D202 – to develop an international standard code for laying and maintenance of continuous welded rail track. Various research institutions and national railway administrations provided a complex…
The hunt for equilibrium The railway vehicle use wheelsets formed of a pair of steel wheels fixed rigidly on an axle. This setup makes the wheels move together on track. The system evolved in time to what we know today: tronconic wheel profiles with inside flanges, rail profiles and inclination, bogies, suspensions and so on.…
Things you find on Spark. In 1972, RTC conducted a series of tests to evaluate the effect on tamping on the track lateral resistance. Their results, published in 1973, have been referenced in numerous other research documents, including the ERRI D202 Reports – the committee that produced UIC Leaflet 720R “Laying and Maintenance of CWR…
Hallade was not alone. His method of track alignment rectification is by far the most used and known but there are quite few other methods for rectification and even proper realignment. One of these methods used a strange curve called involute (or evolvent). It was first described in this book from 1927. Die Absteckung von…
Motto: “I don’t see the code anymore. All I see is blonde, brunette, redhead, negative, adverse.” Cypher Disclaimer: This is not a design guidance. Don’t believe everything you read online. LandXML? LandXML is a non-proprietary data standard on the Extensible Markup Language (XML) format, developed for engineering data exchange. A LandXML file can contain civil and survey…
It was very nice to find this in a standard. Snippet taken from here.
When I hear the name Bernoulli I think about some funny high school experiments of spraying coloured water on paper but also about an infinite loop curve the Roads Professor tormented us in Uni. I would have bet both things were discovered by the same Bernoulli. But no. The more known one, D. Bernoulli, the…
I mentioned in a previous article, The Cubic Parabola – a complicated simplification, that the curvature diagram of the Cubic Parabola increases linearly up to a peak point and then drops down. Only that first section of the parabolic curve can be used as an alignment transition. The curvature diagram of the Clothoid is however…
Prologue One of the main giants on whose shoulders stood proudly Isaac Newton, is the French mathematician Renatus Cartesius. He was the first to label the unknowns in equations by the letters X and Y and also he defined the annotation of powers as superscripted labels X2 . Believe it or not, that was a…
One alignment design homework I had for my students was to calculate the installation coordinates for a simple alignment. This was a long time ago, before Excel was a thing. We were using scientific calculators back then; a lot of typing. One of the submissions puzzled me. All the coordinates were almost correct. The length…
Ten years ago, one of my first British friends asked me “Why 4°?” The Clothoid is by far the most used transition curve for railway and highway alignment design. I wrote about this marvelous curve in an old article on this blog – here. Although the Clothoid is the ideal transition for linear variation of…
If we consider a circular curve of radius R2, tangent to a straight and mark the offsets O1, O2 and O3, measured perpendicular from the circle to the straight and placed at regular C/2 interval we will get something like this: The offsets O1 and O3 are the bases of a trapezoid and O2+V2 is…
I have discussed here the principle of Virtual Transition, used in the UK and in other countries with British inspired track design principles, to evaluate the changes of the cant parameters at the points where the curvature changes suddenly, without the use of an actual, real transition curve. This method of calculation is not however…
All the railway networks have design rules for marking the limit from which it is safe to stable a vehicle on a line, without the risk of obstructing the train passage on the other line of an S&C (turnout or whatever other arrangement). In the UK this limit comes in a pair – Fouling Point…
Aren’t the adjustment switches some really nice devices? On one side we have rails subjected to thermal stress, tending to seriously expand or contract due to the environment temperature, and on the other side no stress is transferred. Smart! We cut the rails in that funny shape, grease the clamp plates, and we let the…
A few years ago (2000 or about then – the year 2000, I mean) I was charmed so much by a new and interesting software that I decided to learn it by myself. I printed its help and started to learn and do things with it. Long time ago, when it didn’t have ActionScript, it…
In my previous posts I lightly covered: The various combinations of these forces define the train driving regimes. These are the following (not sure if all the railway networks are defining theme in the same way): A particular case of this regime is where the falling gradient is so steep that it requires the train…
And then we have the braking force – the third type of force that influences the train movement. As with the others, this force also depends on speed – mainly due to the speed variation of the friction coefficient (μ) for various brake systems (the forces K that trigger the friction are generally the same):
Before reading this, I recommend reading the previous post – The Traction Force – including its disclaimer. When a railway vehicle is required to move on track, it needs to overcome a series of resistance forces. We can call the resultant R of all these forces “the running resistance of the vehicle”. If we consider…
A railway track blog 