# Where’s the point?

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…

# And I wonder, still I wonder, who cut the rails?

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…

# 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…

# Traction force

I’m on my way to explain the principle curvature equivalent gradient. As this is related to a discipline I enjoyed, I choose to go the long way and start with the FORCE. But, before that, a few words of caution: Disclaimer Take this post, and any other that I will write on this subject, with…

# 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…

# How do the rails buckle?

Disclaimer – this includes a back-of-the-envelope calculation. Take it with a pinch of salt. If a steel beam is exposed to an increased temperature, it will tend to expand. If there is nothing to oppose that expansion, then the beam increases in length by ΔL. If, however, the beam’s ends don’t allow this expansion then…

# Which is better – S&C or plain line?

Thank you for visiting this page. I would really appreciate if you could spare a minute and answer the few questions below. I’ll publish the responses with a few comments as soon as enough answers are collected. If you don’t see the form below, please go to this link: Which is better – S&C or…

# 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…

# 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?) ,…