The article I don’t want to write – Virtual Transition forensics
In 1952 the Virtual Transition principle was presented to the Railway Engineering Division of ICE.
Later it became part of the Handbook No 3 Railway Curves.
Why don’t we use angular speed and acceleration for railway track curving calculations?
Have you ever wondered why …
(my plan was to publish this a few days ago – sorry for the delay)
When is the cant negative in LandXML?
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…
The equivalent radius (versine bending)
Prologue One of the 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 giant…
What to abruptly do when you don’t have (the rule of) Virtual Transition?
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…
What’s the degree of curvature?
… or – How to convert a curve into an angle? In the track design handbook we have a too complex formula that refers to “degree of curvature”. Before discussing about the equivalent gradient, let’s see first what this is – what is the degree of curvature? This measure is used in United States in…
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…
Is the surveyed cant the actual cant?
One of the instruments used to survey the track is the rail shoe – an L shaped device placed horizontally on the rail head, that touches laterally the running edge at 14mm below its horizontal arm – see figure 1. The horizontal placement of the shoe is checked using a spirit level. There might be…
A railway track blog 