A richly detailed article that delves into the French TGV speed record, the extra modifications they applied to what was already a high-speed system, and the lesser-known physical phenomena that set a performance envelope for this mode of traction.

Then, in a switch of tone and pacing, admits that profitability potential is likely most important of them all.

This is why networks -- rather than just individual lines -- are critically important. High-speed rail works best when it connects robust local transportation networks that already exist: between cities that they themselves have robust temporal and spatial transport coverage. It works best when faraway cities can be brought within commuting range, or further leisure destinations within daytrip range. Similarly, it works best when it extends the catchment area of an airport, rather than a service positioned to compete against point-to-point flights.

But major infrastructure projects often suffer from messy political and public relations approaches that play up the project's impressiveness and prestige in isolation, while neglecting to emphasize or champion synergistic improvements to other parts of the network. Frequent and punctual "normal-speed" rail isn't as politically energizing, and local transit networks that serve the specific transport needs of a town are hardly exciting to regional audience, but without it, high-speed rail is just an expensive showpiece that doesn't serve a genuinely identifiable transport need. This is a risk with the California HSR as much as it is with ambitious efforts to bring western Europe's successful high-speed services further into the EU's east.