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Comment by innocenat | Hacker News Reader

> But that might apply to metro and regional rail more than long distance, so it might not be relevant here.

Shinkansen at peak time runs more frequently than even some subways line in Japan. The Tokyo-Omiya section (shared between Tohoku/Joetsu/Hokuriki Shinkansen, which E4 also ran on) runs at peak of 15 trains per hour per direction, or 4 minute heading. (The Tokaido Shinkansen is even more impressive at peak of 16 trains per hour per direction.) The loading time is very, very relevant, and it's why E4 has been phrasing out for a long time already.

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In many instances, long distance lines have more than one platform track per line track. So dwell could happen in parallel. It's still an issue, but could be mitigated.

My guess is that outside of the peak, these kind of trains are not necessary. And the peak can apparently be accommodated without them. So there may be some times where they would be economically advantageous, but not always - meaning it could make sense to have some double deckers.

But for train services, it makes sense to have uniform fleets, both to reduce maintenance costs and increase dispatching flexibility. Trains should also have the same performance profiles and dwell times (as mentioned before). So any small peak time advantage is undone by the bad economics of having a non uniform fleet.

Nice idea on double platforms! It would be neat to see a world where that was done uniformly

But I agree, that world is not ours.

Look at the track layout for the Tohoku Shinkansen [1], you'll see that on most stations, there are either two platform tracks per direction, or one platform track and one passing track. In this world, on mainline rail, stations usually have more tracks than the lines they connect to. (Yes this is not uniformly so, but trains don´t have to uniformly stop at all stops, they can skip smaller ones to reduce dwell time pressure)

Btw, more station tracks than line tracks can also happen on regional rail, for example check out the downton section of RER C in Paris (the yellow line) [2].

[1] https://www.haisenryakuzu.net/documents/jr/shinkansen/tohoku...

[2] http://cartometro.com/cartes/rer-idf/

OH I thought you had meant double-decker platforms for a single track, to serve both levels of a double-decker train.

For sure more platforms than lines in is a good idea that exists today.

I am not actually familiar with Tohoku/Joetsu Shinkansen (living in Osaka), but I can tell you that for Tokaido Shinkansen, dwell time is still very much a problem even with parallel platform. For Tokaido Shinkansen, while the door only open for a minute or so, by the time we are leaving a station, the next train (running 3-4 min behind) is already pretty much pulling into the station.

Previously Tokaido Shinkansen only can only runs 14 train per hour (note that unlike Tohoku/Joetsu, Tokaido Shinkansen runs 14 tph over 350km of tracks, and not all trains has same stops), but after some optimization, including a procedure to reduce dwell time by a few seconds, they were able to push that to 16 tph.

Glad to hear it, thanks!

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