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…
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):
… 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…
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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…
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 