The Tohoku Shinkansen stretch between Tokyo and Sendai would be a great addon for TS20xx. It would be a good addon for TSW2 as well, but it may be too massive for it, so that's why I'm suggesting it for TS20xx. (Yes, it's old, but realistic.) The line length is approx. 350km. There would be a nice variety of services. The rolling stock would be: E2 1000 series The E2 1000 series shinkansen is one of the best looking shinkansen trains in my opinion. The max speed is 275km/h. It's used on Yamabiko services from Tokyo to Sendai and Morioka. E3 series The E3 series shinkansen is used on Tsubasa services from Tokyo to Yamagata and Shinjo. Max speed is 275 km/h. It runs coupled to E2 series operated Yamabiko train between Tokyo and Fukushima. E5/H5 series The E5 and H5 are running on Hayabusa services from Tokyo to Aomori and Hokuto and in future, Sapporo. The max speed is 320km/h. It's the fastest shinkansen train in commercial service along E6 trains. E6 The E6 is used on Komachi services between Tokyo and Akita. Max speed is 320km/h. It runs as coupled with E5/H5 operated Hayabusa service between Tokyo and Morioka.
That ES/HS and E6 look sleek. The only possible qualm is the length; the longest route in the game is South West China High Speed and it's a very rarely used route in the Workshop and in third-party products, so since Japan tends to fall into this category, you might have to accept a portion of the route at best or be willing to obtain two or even three different DLC to get the full route. Another option is to research and build it yourself if you think you can figure that out.
Excellent idea and speaking of the E5 & H5 bullet trains they are actually designed to run on the second longest railway tunnel in the world the Seikan Tunnel 53 km 33 miles. In the future this might be joined by another DLC route Hokkaido Shinkansen Hakodate Aomari. At Aomari you're going to get this message provided you install Hokkaido Shinkansen Do want to continue the service to Aomari Yes or No?
I'm pretty sure Union Workshop is already working on this. Here's a link to their blog with a teaser of the E5 Shinkansen. https://m.weibo.cn/u/5051373059?fbclid=IwAR3EHaqcG2PahalaT-quRbUkF2Q-bavRu56V0jDyq_1x-wrDxMWdLV8aoJY
They are not always 100% accurate. That's the only problem with Google's. Though I do use that to get some idea what is being said and try to figure it out from there.
This is what Google gives me "More than Speed" The Tohoku Shinkansen, opened in 1982, is currently the fastest operating high-speed railway in Japan. In this work, we created the Sendai-Morioka section of the Tohoku Shinkansen, which is about 171 kilometers in length. In this interval, you can experience the 320km/h high-speed gallop of the E5 series car, It should be noted that the first release of this work will be released on JustTrains.net. Whether to log in to Steam in the future still needs to wait for further news @UnionWorkshop : #worklog# 2021.8.25 "Go to the Northeast" -part 2 This week, we submitted the first full beta version of the new work "THK" to the publisher JustTrains. This means that the main development work of this work has ended, and the work will meet with you as soon as possible after the completion of the QA test. During this period, we will continue to disclose relevant information about this work on Weibo, so stay tuned~ And not much else for more than a year
Sendai to Morioka gives a bit of future DLC potential - the E6 for example (most Haybusa services are an E5+E6 as far as Morioka where the train splits for Akita and Aomori) You also have E2s on some stoppers. And of course there will be an H5 Reskin in 5 mins
https://f.video.weibocdn.com/000IwJE8gx07Q0eiviRa01041200ccTU0E010.mp4?label=mp4_hd&template=852x480.25.0&trans_finger=62b30a3f061b162e421008955c73f536&ori=0&ps=1CwnkDw1GXwCQx&Expires=1632851658&ssig=w/sfAB73W/&KID=unistore,video The above link has a Video Showcasing the E5.. That was posted a week ago.