>>1196792That is an issue which more relates to the fact that many highly populated centres are too close for HSR to make a difference. See Rhein-Ruhr area. Where there is a difference to be made, it's in sections of rail connecting vital cities like Frankfurt with Köln, or München with Nürnburg, or Leipzig with Erfurt. Many sections do need upgrading to true HSR, but for many sections, the mainlines have to share capacity between RE trains and IC/EC/ICE trains. S-Bahn sections tend to be more in branch lines or dedicated track and RB trains often run on branch lines which are only really used by RB trains and freight trains. As such, the main problem is what you do with the existing line. Upgrading a mainline to 280 km/h might make journeys faster and make it true HSR, but you're having to deal with the fact that slower RE trains have a top speed of 160 km/h. Scheduling and sections of 4 tracks to allow for regional trains to be overtaken by faster long distance trains can help, but they still create issues where the RE and RB trains will be in the way of the faster IC trains doing up to 200 km/h and the even faster ICE trains.
