[lmm]

> The Shinkansen runs the fastest Nozomi service about every ten minutes throughout the day at around 5 trains per hour on the most popular routes like Tokyo to Osaka, then during peak hours there's another 5 added in on top of that as well.

Your numbers are out of date. The current timetable is 16 trains per hour per direction (12 Nozomi and 4 slower services that stop at more stations) on a single line - some go further than others but they're all going to the same places at least as far as Nagoya (and all but one go to Osaka).

> There is generally about one train every 10 minutes per platform at a station in my experience, but of course there are usually well over 20 platforms per big station, it's not like there is one platform with a train stopping every three minutes.

The stations have multiple platform faces connected to the same line, even intermediate ones, but in general it's a two-track line, one up, one down.