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.
Can you help me to understand this part?
I would not call the Tokyo subways lines (both companies) very fast when riding a local train. I went to Paris for a week and found the metro lines fairly similar.