You are correct, taking the reference speed as measurement is not a valid line of reasoning. The average speed is higher, the speed is lower the closer the sta

You are correct, taking the reference speed as measurement is not a valid line of reasoning. The average speed is higher, the speed is lower the closer the stations are together, but the speed also depends on the line; i.e. the Ginza line added ATS(automated train stop, added in 1993). I just learned that Paris' Line 14, that went into service in 2022, also drives at accelerated speeds, it's the first line with ATS in Paris. I think the main problems that need to be addressed with respect to higher speed transportation are the following: 1. the breaking system needs to be assisted (ATS) 2. the railway needs to be replaced and reinforced 3. turn angles can't exceed a certain degree 1 and 3 are a design issue that isn't really addressed in older metro system, and 2 is probably a political problem. Contrary to my previous belief it seems that France is at least trying to address some of the points in their metro extensions, which is nice.