Tobu Skytree Line Operating Bottleneck?

[Jcarlton]

I was watching this video of a station on the Tobu Skytree Line and it occurred to me that operations through the station didn't look right. I would expect that trains making a stop in the loop tracks would be held to allow the trains not making a stop to pass. Yet in 90% of the cases here, the stopping train would depart and a very short time later a nonstopping train would follow it. I checked the map and there is the advantage to holding the stopping train because the stations on both sides of this one are two track stations. But that's not the way it's done here.

https://www.youtube.com/watch?v=HEmMOwWVXyU#t=46

Map:

https://www.google.com/maps/search/%E5%B9%B3%E6%97%A5%E6%9C%9D%E3%81%AE%E6%9D%B1%E6%AD%A6%E3%82%B9%E3%82%AB%E3%82%A4%E3%83%84%E3%83%AA%E3%83%BC%E3%83%A9%E3%82%A4%E3%83%B3%E9%90%98%E3%83%B6%E6%B7%B5%E9%A7%85/@35.7347097,139.8197915,18z

Why have loop tracks if you don't take advantage of them?

[bikkuri bahn]

Good video, this youtube contributor has a lot of good ones, especially for those interested in rush hour train operations.

 

The station in question, Kanegafuchi, is on the last stretch of the line before Asakusa, which is full of curves and speed restrictions, so all trains are going quite slow.  Being that this is the rush hour, the train spacing will be quite close.  Probably it's better to keep all the trains moving rather than hold the locals up for the limited stop ones.  Also, a good number of those through trains are actually bound for the Hanzomon Line via the connection at Hikifune, rather than the Asakusa terminus.  Likely the locals will stop and wait for the through trains at Hikifune, as well as to allow a cross-platform transfer for passengers. 

 

The real bottleneck, apparently, on this line is the Asakusa terminal itself- the platforms there are long enough for only 8 car trains, so the standard (for Tokyo) rush hour train length of 10 cars cannot be accomodated.  10 car trains are reduced in length at Kita-Senju (where a good portion of commuters transfer to other lines, including the Hibiya Line) as result.

Edited October 19, 2014 by bikkuri bahn

[kvp]

 

10 car trains are reduced in length at Kita-Senju as result.

Is there any information online about this? How do they split up the trains? What happens with the extra cars? Do both parts continue or just one part? Do they get added back to the same sets or the first one that comes along?

[railsquid]

It would surprise me if they do that (though happy to be proven wrong). AFAIK the Asakusa bottleneck has been side-stepped by through-running with the Hanzomon line, and Asakusa (with relatively poor onwards connections) is pretty much a side-show used mainly for limited express trains (a bit like the Keisei Ueno terminus). At least that was the impression I got the last time I was there.

[bikkuri bahn]

It would surprise me if they do that (though happy to be proven wrong). AFAIK the Asakusa bottleneck has been side-stepped by through-running with the Hanzomon line, and Asakusa (with relatively poor onwards connections) is pretty much a side-show used mainly for limited express trains (a bit like the Keisei Ueno terminus). At least that was the impression I got the last time I was there.

Yes, pretty much that.  Most (?) commuters get off at Kita-senju and transfer to other lines, or continue on the Hanzomon Line to get into central Tokyo.

Edited October 19, 2014 by bikkuri bahn

[bikkuri bahn]

Is there any information online about this? How do they split up the trains? What happens with the extra cars? Do both parts continue or just one part?

 

The rear portion is left behind, and then continues on as an empty coaching stock movement, presumably to the the layover tracks past Kita Senju just before Ushida Station.

 

 

You can see those layover tracks at around 1:50 on this clip:

*also note at 12:45, the almost simultaneous departure of the Hanzomon Line train and the viewer's (a local for Asakusa) train, running in parallel for a short distance until the Hanzomon Line train sweeps under to access Tokyo Metro's Oshiage Station. These simulataneous departures from both sides of the up platform are a feature of the Hikifune Station scene.

Edited October 19, 2014 by bikkuri bahn

[kvp]

Interesting operation! It would seem more logicial to just increase the length of the tracks at the few stations where the trains don't fit. Good to know that real railroad companies have the same problem of too short platforms to deal with.

[railsquid]

Interesting operation! It would seem more logicial to just increase the length of the tracks at the few stations where the trains don't fit. Good to know that real railroad companies have the same problem of too short platforms to deal with.

 

The Asakusa terminal is the issue - they have evidently struggled to fit in 8-car trains, the platforms at the far ends especially are incredibly narrow (I've got some photos somewhere), and there's no obvious space to expand.

[nartak]

Let me follow some from daily Tobu line passenger....

Tobu Isesaki line (sorry, I don't like the term "skytree-line", it is not so sophisticated like that).

As everyone points, Asakusa station has issue of the platform length.  However, after Hanzomon line through operation (too long even in Japanese and we just call "Han-Choku") now in steady state.  So all the section express train at peak hour bounds for Asakusa is now with 8 car and not splitting anymore at Kita-Senju station.

However, even we have Han-Choku now, still many passenger transit at Kita-Senju to take Chiyoda line.  This is because...

1. Chiyoda line is the shortest option to get to Otemachi area even it is packed with people.

2. Number of Han-Choku train at peak hour may not be enough (only 6 to 8 per hour) to stimulate passnger to migrate to Han-Choku train.

Anyway, passengers are happy if Tobu can carry them to Kita-Senju.  There is not much passenger between Kita-Senju to Asakusa.

The other bottleneck is actually Hibiya line (Tobu Isesaki line local train) which was designed with 18-meter cars and not having enough capacity.

[bikkuri bahn]

Thanks nartak.  That Kita Senju video was pretty old, should've known it may be outdated. Frankly the older operations are more interesting than the simplified ones today, though I suppose customers like you appreciate the efficiency of the latter.  Interesting about the 18m car lengths. Perhaps because the Tobu Isezaki Line/Hibiya Line run-through was the first(?) run-through operation, they had to settle on the standard car length then on the Tobu Isezaki Line, which was 18m(?). Or maybe it was Tokyu... 

[nartak]

Thanks nartak.  That Kita Senju video was pretty old, should've known it may be outdated. Frankly the older operations are more interesting than the simplified ones today, though I suppose customers like you appreciate the efficiency of the latter.  Interesting about the 18m car lengths. Perhaps because the Tobu Isezaki Line/Hibiya Line run-through was the first(?) run-through operation, they had to settle on the standard car length then on the Tobu Isezaki Line, which was 18m(?). Or maybe it was Tokyu... 

 

Dear Bikkuri Bahn-san,

 

You are right.  It was more interesting before Han-Choku and Tokyo Skytree.  I remember they had 10 car limited express to Narihirabashi and let people to change to Asakusa line at Oshiage, semi express train going through from Asakusa to Isesaki (semi express A), semi express bounds for Tobu Nikko/Utsunomiya....etc

 

Regarding Hibiya line, it seems Eidan and Tokyu was for 18m while Tobu wanted 20m according to wikipedia.  And after 50 years of operation, they finally changing to 20m cars in near future...

[bikkuri bahn]

Ah, so it was Tokyu and Eidan then.  A quick check shows Tokyu's first 20m stock was the 8000 series starting from 1969, six years after the introduction of, for example, the Tobu 8000 series, a 20m length design, and more than a decade after the introduction of the seminal JNR moha 90/101 series.