crocal

We did use actual data from existing lines to measure the gap between our models and reality. We were +/- 5% accurate.

Ahoi! Participated to the development of a simulation tool for that purpose. Many factors need to be taken into account:

- The gradients of the track

- How agressively you want to drive at different time of the day

- How many trains

- The timing of the trains. When one train brakes, it can power another one that accelerates at the same moment

- The efficiency of the power chain

- The resistance model of the train

With so many parameters the results can be quite volatile. However, rule of the thumb in the business is that 30% saving can be achieved with good energy management. Hope this clarifies a little.

Update: bullet points

What else is new? This was already well known among grad students in the late 90s. We even knew there was some kind of hierarchy, with one of the student acting as «political officer».

Unrelated question: how did you manage tabular data in git? It’s always a struggle to diff and merge changes.

Except the stated goal here is to replace these sensors with GPS.

I cannot agree more with the author’s point of view. As an illustration, many people want to use GPS for the safe positioning of trains in the European Train Control Systems. This makes the space sector happy because it justifies the expenditures incurred for putting things like Galileo in orbit. However, in a pre-war check exercise, one immediately come to the conclusion that all European trains would crawl to a stop in case the GPS is jammed or interfered with. We were not very listened to… until Ukraine.

Critical infrastructures should not depend from things that are located in space or on the other side of the planet. These are one of those things were market logic should be anticipated with regulations (we can’t wait for the next Titanic). Another point touched by the article.

I concur. I broke my wrist.

This correct. Power lines wear induced by pantographs is the limiting factor for TGV top speed.

The engineer that can solve this problem will allow top speeds in the range of 400/500 kph on /existing/ TGV tracks. Much better problem to solve than hacking a lame hyperloop.

There is something very wrong going on in Germany AND France where, despite the nice speeches, investment in railway infrastructure is being run into the ground. If nothing changes, expect disaster-level quality of service within a 5 years time.