JAPAN | High Speed Rail

[M-NL]

It may be just cosmetic, but company identity is also very important. Have you realised that except for the N700, which is now used by 3 companies, and the future E7/W7 I can't think of any other post-JNR model in Japan that is not company exclusive.

Changing gearing may cost more, but a 500 may not be able to reach the travel times of the other trainsets because of it. Especially since the 700 was designed to be quicker to 270 km/h then the 500. On the other hand: The 500 replaced the 300 which was even slower.

[Silver Swordsman]

Originally Posted by M-NL

In fact given that the 700T does 300 km/h there is no reason why the 800 couldn't also. JR Kyushu could also have asked for N700s with the 800 nose design just to differentiate themselves from JR West. In a few years you will only see N700 variants south of Tokyo (Not that they are bad, but it's to much of a monoculture for me)

700T bogies are based off the 500系 rather than 700系 to ensure 300+ km/h operating speeds. The record for THSR is 315 km/h, although the system is future-proofed for speeds of 350 km/h.

Originally Posted by M-NL

Thing is the difference between service speed and design speed. The 500 series might have a higher top speed then the N700, but accelerates slower because of it's taller gearing. I wonder if they changed it now that the 500's are limited to 285 km/h in Hikari/Kodama service.

Ah, thanks for making that clear. That was what I was wondering--so they traded the taller gearing for faster acceleration. Just wondering; is it possible to have multiple gears for trains (kind of like a bicycle)? :P

[M-NL]

Yes, that exists. The DB V90 and the SNCF BB 8500/17000/25500 all have this feature, but can only be switched while stationary. Also more modern diesel hydraulic trains with Voith transmissions have multi stage torque converters, effectively creating multiple gears. In the past a lot of trains with clutch and gearbox drive have existed.

[Silver Swordsman]

Originally Posted by M-NL

Yes, that exists. The DB V90 and the SNCF BB 8500/17000/25500 all have this feature, but can only be switched while stationary. Also more modern diesel hydraulic trains with Voith transmissions have multi stage torque converters, effectively creating multiple gears. In the past a lot of trains with clutch and gearbox drive have existed.

Is this... in any way possible for electric bullet trains? :P

[loefet]

Possible? Yes.
Would they do it? Most likely no.

It's too complex work well in the real world, it would require a lot more maintenance than what is necessary today. Also trains like the N700 works very well without it, and still have superb performance. Like it can easily do 330 km/h and accelerates faster than any other HSR train, it can even accelerate at the same rate as a Transrapid train all the way up to 270 km/h.

[M-NL]

Exactly. The problem used to be the power switching technology. Resistor control DC and 25kV AC) or transformer stepping (15kV AC) power control was slow reacting and because of the steps it wasn't easy to go to the traction limits. Nowadays with the 3-phase IGBT control that problem doesn't exist anymore.

But one thing remains interesting there: A TGV has only 8 out of 26 axles driven, an ICE2 8 out of 32, an ICE3 16 out of 32 axles. The Shinkansens are a different story: the usual layout is all axles driven except for the end cars. That means less power per driving axle and potentially less traction problems. Several bogies may fail before the train needs to be taken out of service. Downside: it's more expensive to manufacture. But given that a 16 car 700 series costs 4 billion yen (about 30 million euro) a Shinkansen set is still much cheaper then an 8 car TGV POS at around 35 million euros (taken from the Fyra tender). The extra cost of the TGV probably goes into the multi system setup and the fact it needs several ATC systems. The Shinkansen N700 is 25 kV 60 Hz and DS-ATC only.

[big-dog]

pics taken by me 2 wks ago



Shinjuku to Hakone "Romancecar"





Ueno-Narita skyliner