The other Bernoulli boy and his lemniscate

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…

Pi is never 3.14 in engineering

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…

Three points = a circle

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…

Cant deficiency converted in percentage of g

As demonstrated in a previous post here: https://pwayblog.com/2015/10/29/11-82_cant-deficiency-un-compensated-acceleration-pway/ , the cant deficiency is the conventional representation of the uncompensated lateral acceleration. And since cant deficiency is an acceleration, we can easily represent it as a percentage of g, the gravitational acceleration. The formula that relates the cant deficiency D to un-compensated lateral acceleration is: The…

What should I write about?

Hello!I am trying to get back to writing on this blog. It would really help me a feedback from you. What do you think I should write about?What railway track subject will interest you the most?Please select only two or maximum three from this list (careful, you will not be able to vote twice). If…

Versine artefacts?

Motto: If you can’t explain it simply, you don’t understand it well enough. (Easy for you to say…) Einstein Well, hello again, dear reader! Before moving on from the TGSD Calculator allow me to explain what it measures, without any reference to waves and filters, without frustration or passive-aggressiveness (is that an actual word?) ,…

What is the TGSD Calculator?

This post follows up from the Faith of TGSD Calculator. Before my four year too late discussion with David Marriott I wrongly believed that the TGSD Calculator computes a special kind of uncompensated accelerations that appear only at the points where any design element changes to another and turns those into a wave-like shape that…

The Faith of TGSD Calculator

Motto: “I am not the Messiah!”,  Brian [Later edit: I wrote this during the pandemic, not in a very happy state of mind, nostalgic about good old and normal times, and dreaming of white whales. It is a personal opinion and, to a degree, an expression of powerless frustration. Don’t take it too seriously!] For…

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…

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…

Relative position of adjacent tracks

General considerations The relative position of  railway double or multiple adjacent lines is of critical importance for level crossings. On canted tracks, the road traffic is affected if the level crossing does not provide a good riding plane, especially for long vehicles or the (sometimes expensive) low profile ones. This is why the design of…

The orphan rule of cant design over a reverse transition

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…