About The Ōu Main Line (奥羽本線, Ōu-honsen) is a railway line in Japan, operated by the East Japan Railway Company (JR East). It connects Fukushima Station through Akita Station to Aomori Station. Since the opening of the Yamagata Shinkansen on July 1, 1992, the Fukushima–Yamagata section (as well as the Yamagata–Shinjō section since 1999) is sometimes referred to as the Yamagata Line. I am recommending the section between Fukushima and Shinjō, which would be 148.6 km (92.33 mi) Rollingstock 701-5500 series 719-5000 series E3-2000 series E8 series
It'd be interesting to see since the line has good service variation in a stopping service and essentially a limited express. Although it features a Shinkansen, since the line is at ground level and features level crossings, the E3 or E8 series wouldn't run at bullet train speeds but rather at limited express speeds (~150km/h in my memory). At the same time the 719-5000 series, although heavily resembling the 211/213 series EMUs, since they share the line with Shinkansen sets, are standard gauge rolling stock as opposed to the typical JR cape gauge for ordinary trains.
Good suggestion but following on from discussion in the other threads, with just UW seemingly working on Japanese content and still mired down with Tadami, who is going to build all these routes and new trains? It does make me wonder though why UW started with such a large project rather than something a bit shorter and simpler to cut their teeth. Would also have given a quicker proof of concept for JP stuff in TSW that in turn might encourage DTG to do some routes from the region themselves or actively seek out new third party partners.