I find it interesting how the massive Kanto area rail network was actually opened in such a piecemeal fashion, with many lines extending 3 or more times before reaching its final length, and often just one or two stations at a time. The main circle of the Oedo line is already one of the longest opens at once, but the line as a whole was actually opened in three segments. With that in mind, Tsukuba Express appears to be the longest (non-Shinkansen) new opening in the past 30 years?