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…

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…

Vehicle rollover speed

The Santiago de Compostela derailment occurred on 24 July 2013, when a high-speed train, travelling from Madrid to Ferrol (north-west of Spain) derailed at high speed on a 400 m radius curve, at Angrois, in Santiago de Compostela. Around 140 people were injured and 79 died. Data from the train’s black box revealed that before the start of the curve the train was travelling at…

Mauzin (Hallade) track measurement car

The measurement and analysis of track geometry is carried out regularly by all the railway infrastructure administrators in order to obtain data from which the track quality is established and the maintenance can be scheduled (Cope – 1993). Historically, the use of track inspection cars can be traced back to the early 1920’s in France…

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…

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…