How come Japan didn't unify on 1,500 V DC for overhead electric power?

[Sacto1985]

Since I seem to have difficulty figuring this out (unless I'm really fluent in Japanese), I really have to ask this question: how come during the JGR (and eventually JNR) nationalized control of the railroads, the electrified rail lines in Japan did not standardize on 1,500 V DC overhead power? 

 

I know that in Hokkaido, most of the Tōhoku region of Honshu, the Hokuriku region of Honshu and in most of Kyushu, overhead electrical power is 20,000 V AC 50 or 60 Hz instead of 1,500 V DC. Was 20,000 V AC adopted because it suited the colder weather extremes better? (Which kind of doesn't make sense since Kyushu uses 20,000 V AC 60 Hz). I'm sure there has to be good reasons why it ended up this way. 

 

Mind you, it was obvious that the Shinkansen needed a lot more power, and that's why on the 1,435 mm gauge Shinkansen lines they standardized on 25,000 V AC power.

[katoftw]

Because different railways use different helpers/designers to create their systems.  Some used British system and some used American systems at different times of building their own railways.

[Kabutoni]

For JR East: JNR took on 20kV 50Hz AC in North Kantō (and beyond) because of it would not interfere with measurements of the nearby terrestrial magnetism observatory in Kakioka near Mt. Tsukuba in Ibaraki-ken: http://deadsection.image.coocan.jp/dead_sec/toride/toride.htm 1500V DC interferes with its measurements, which are a little bit more important than running trains. For this same reason, the Kantō Railway is not electrified and the surrounding area is hardly urbanised because of the expense of laying down an AC/DC railway network and corresponding rolling stock. Then it was decided to continue developing the AC network northward because of better cold-weather resistance and a higher power output for the heavy freight trains (note that traditional AC-only JNR electrics, like the once immensely popular ED75 are much smaller).

 

For the other areas, it's about the same story, but with electrical power plants owned by local governments and/or private companies.

 

Shinkansen uses AC because of the reliability and lower heat development at high speeds and power need. I'm sure people with more knowledge can elaborate on this matter.

 

Anyway, it has nothing to do with different companies and helpers of the systems, as the AC system was adapted way after major foreign intelligence (e.g. Iwakura related missions and foreign groups of engineers) was needed, as IIRC no private company used any form of AC during their startup or conversion to electric at any time. The only exception is the Tsukuba Express, which was developed in the late 1990s. Mind you, AC is very expensive for railway companies.

Edited April 11, 2015 by Toni Babelony

[Densha]

@katoftw

So far I know Japan's national rail network is not a collection of private lines as they are in many European countries, but a network actually built by the Japanese government. Lines originally built by private companies are still largely owned by the same companies nowadays. I need someone to confirm this though.

 

(Of course there are a few exceptions of lines that went from national railway company to private company or vice versa, this is just a general observation.)

[Sacto1985]

For JR East: JNR took on 20kV 50Hz AC in North Kantō (and beyond) because of it would not interfere with measurements of the nearby terrestrial magnetism observatory in Kakioka near Mt. Tsukuba in Ibaraki-ken: http://deadsection.image.coocan.jp/dead_sec/toride/toride.htm 1500V DC interferes with its measurements, which are a little bit more important than running trains. For this same reason, the Kantō Railway is not electrified and the surrounding area is hardly urbanised because of the expense of laying down an AC/DC railway network and corresponding rolling stock. Then it was decided to continue developing the AC network northward because of better cold-weather resistance and a higher power output for the heavy freight trains (note that traditional AC-only JNR electrics, like the once immensely popular ED75 are much smaller).

 

Well, besides the issue with the terrestrial magnetism laboratory, the fact 20,000 V AC overhead power can operate in lower temperature conditionx explains why on most of the Tōhoku region, Hokkaido and the Hokuriku region run on 20,000 V AC power. Mind you, how come the Chūō Main Line from Takao west to to Shiojiri--which is in the Japan Alps with its cold winters--didn't adopt 20,000 V AC overhead power? Or why most electrified lines on Kyushu with its generally warmer weather use 20,000 V AC overhead power?

[railsquid]

@katoftw

So far I know Japan's national rail network is not a collection of private lines as they are in many European countries, but a network actually built by the Japanese government. Lines originally built by private companies are still largely owned by the same companies nowadays. I need someone to confirm this though.

 

(Of course there are a few exceptions of lines that went from national railway company to private company or vice versa, this is just a general observation.)

 

Some quite substantial sections of line, including the San'you Main Line, Touhoku Main Line and Yamanote Line were built privately and later nationalized. See: http://en.wikipedia.org/wiki/Railway_Nationalization_Act

[katoftw]

Well, besides the issue with the terrestrial magnetism laboratory, the fact 20,000 V AC overhead power can operate in lower temperature conditionx explains why on most of the Tōhoku region, Hokkaido and the Hokuriku region run on 20,000 V AC power. Mind you, how come the Chūō Main Line from Takao west to to Shiojiri--which is in the Japan Alps with its cold winters--didn't adopt 20,000 V AC overhead power? Or why most electrified lines on Kyushu with its generally warmer weather use 20,000 V AC overhead power?

As much as I've been told I'm incorrect.  Your answer still is timeframes, money, effort, ability, technology.

 

Kyushu for example went from steam, to diesel to 20kV AC.  Due to the time they electrified their lines (in the 90s), they went with the most modern system available to them at the time.  They mostly in general bypassed early electrification systems of the 1950s/60s/70s.  I'd hazard a guess Hokkaido and Hokuriku is similar in situation due to there remoteness and electrification timeframes.

 

Other regions and/or lines using 1500V DC don't have the time, money, resources or ability to make the change from what was first built in 1950s/60s/70s.  They stay with what they have.  Changing a system from one type to another can require a major shutdown of the line.  Just something that cannot be done in today's world.

Edited April 12, 2015 by katoftw

[Kabutoni]

Here is a very short summary on electrification in Japan:

 

DC: the first to have electrified tracks was the Kyōto Electric Railway, a tram company, in 1895. The first full-on railway company to have an electrified network was the Kōbu Railway in 1904, which was taken over by JGR in 1906 and incorporated in the Chūō Line. Both electrified at 600V DC, but the Chūō line was rebuilt to 1200V DC in 1927 and again rebuilt to 1500V DC in 1929. This became the standard for the JGR/JNR until the introduction of AC voltages for direct operations. Private railways held their own standards, mostly 600V or 1500V DC, all according to the transport volumes and if they would have direct through traffic on other networks (either private or JGR/JNR).

 

AC: this is a little bit more complicated, as Japan has three AC regions (excluding Shinkansen) with either 50Hz or 60Hz frequencies. There are several reasons for this, which I will explain below. First of all, emerging from the rubble of the WW2 and the restraints of the Allied Occupation until 1952, JNR targeted at electrifying the whole of Japan. Europe, with France in particular, was seen as the great example for modern AC electrification and thus AC was chosen for the future. Better reliability at any operating temperature and more powerful engines were good reasons to begin research and tests with AC.

 

With the terrestrial magnetism laboratory in Ibaraki in mind, the frequency of the electrification was important. There were some companies in the region of the terrestrial magnetism laboratory with DC electrification, but their speeds were low (40~50 kph) and voltages as well (600V), thus incompatible with the needs of JNR. These were the Ibaraki Transport Suihin Line (until 1966) and the Hitachi Electric Railway (until 2005).

 

Because there was the wish to electrify the network in the north Kantō and beyond, but the Ibaraki region was a hindrance, AC was chosen as the main electrification method. JNR did the first experiment with 20kV 50Hz in Tōhoku first with the Senzan line in 1955 and proved successful enough to electrify the whole of Tōhoku and a part of Hokkaidō with the same voltage and frequency. The same frequency (50Hz) is also used by Tōkyō Electric and Tōhoku Electric.

 

For Hokuriku, which was unelectrified until 1969, AC was chosen as well, but with 20kV 60Hz, as not to interfere with the frequency of local power plants. This was the same case for the Kyūshū region (1976) where the frequency was important not to interfere with the power plants.

 

As for the Chūō line, there were actually plans to convert the line to AC, as well as the Sanyō line. This proved far too expensive and complicated for what it was worth in the end. Even for JNR.

 

If AC was the right choice for Kyūshū or not, I will not go into, but it proves a challenge for JR Kyūshū to run trains on this voltage. JNR had less problems with spendings on rolling stock and operation costs, as it was government owned and didn't need to turn out a profit. JR Kyūshū needs to at least break-even to be able to operate, hence some electrified lines see DMU operations on local trains (KIHA 220), rather than EMU. This is the same on the Hokuriku Main line with the newly opened 3rd sector companies. JR East can offset operations of AC EMU with the profit it makes in other areas. It's not surprising then to see JNR had a massive deficit at their split up.

[miyakoji]

Interesting Toni, thanks.  So AC is fundamentally more expensive?

[Sacto1985]

While AC was more expensive, it had one huge advantage over DC: it worked well in colder climates. That's why the Tōhoku region of Honshu and any lines on Hokkaido that could be electrified used 20,000 V 50 Hz AC; in a way, that's why when the Hokuriku Main Line between Tsuruga and Itoigawa was electrified, they likely chose 20,000 V AC 60 Hz because electric trains could operate well right through the very snowy winters the Hokuriku region can experience.

[Kabutoni]

Interesting Toni, thanks.  So AC is fundamentally more expensive?

 

Yes, as rolling stock needs AC to DC conversion equipment for the traction motors and other electronical equipment. Well, it's relatively more expensive to DC equipment, which is standard in Japan. The infrastructure is also more expensive to build (I don't know about maintenance, but that'd probably also be more expensive), as everything needs to be heavier to deal with the higher voltage.

 

The costs are the main reason why railway companies like the Kantō Railway are all DMU operated and the JR East Jyōban Line local service stops at Toride. I'm sure JR East would gladly extend all services to Tsuchiura, as that is also a potential commuter hub, as well as a tourist destination, but the sheer costs of investing in even more 10+5 E531 Series wouldn't do any good. Keisei Group as well would long have the Kantō Railway lines electrified, but it's just too darn expensive.

 

Compared to the high-recycling/throw away rate and value of DC rolling stock, AC and AC/DC combined rolling stock is used until the wheels fall off. You'll see the 'newer' local AC and AC/DC rolling stock of JR East (E721, 701 and E531) will be used until they fall apart. Only recently the E501s have been upgraded because of the costs and the old 415-1500s are being retired in favour of 5-car E531s on the Mito line for example.

 

Unfortunately, I don't have any hard data to back this up, but I've had talks with people about this (from train drivers to regular rail fans) and they always gave me these explanations.

[katoftw]

That is very good information Toni.  Of the articles I have read, they have said that certain technologies were used that were available and for certain reasons at the time.  But the reasons were not as in depth as you explanation.  Thanks.

[Kabutoni]

That is very good information Toni.  Of the articles I have read, they have said that certain technologies were used that were available and for certain reasons at the time.  But the reasons were not as in depth as you explanation.  Thanks.

 

My pleasure. I've been learning a bit as well. It's mostly compiled information from the Japanese wikipedia an answer on Yahoo! Questions and the website I mentioned earlier.

 

---

 

By the way, I've had this thought about the Kantō Railway and electrification. Maybe we will see this happen in the future, as battery operated trains are getting more popular nowadays. Beyond the Mizukaidō depot, the area in which the Jōsō line runs becomes AC territory, so there is no chance of electrifying DC towards and beyond Mizukaidō. Mizukaidō is a semi-terminal station for most runs from the JR East Toride station. From Mizukaidō northwards the line becomes single track and less frequently operated. Speeds however exceed 90 kph, as stations are much further apart from on the double-track section.

 

Anyway, all trains however are required to enter the AC region in any operation case. This made me think that it'd make sense to stop overhead wires just after the Mizukaidō depot and have battery/hybrid operation BEMU (Battery Electric Multiple Units) to Mizukaidō and beyond. This is the same concept on the JR East Karasuyama line with the new EV-E301 Series ACCUM that can operate on both DC overhead wires and as a battery operated unit on non-electrified tracks. JR Kyūshū did the same with a 817-1000 Series that was converted to the same concept.

 

Now, the question begs if BEMU are financially viable, can offset the AC costs and is actually cheaper than these intense DMU operations. From a logical point of view it should, but there are always twerks with modern and unexplored technologies. You may never know... Just a thought... If so, this could prove an excuse to link the Jōsō line to the Tsukuba Express via the depot tracks near Shin-Moriya, providing a direct connection to Kitasenjū, Akihabara and Tokyo sta. in the future.

[kvp]

AC can be cheaper when you operate off the public grid and feed back to it. For example Hungary started using AC electrification in the 1920-ies when the AC electric locomotive was invented. Catenary costs are higher, but substations become simple transformers and can be spaced further apart. Also you can reach higher speeds. AC-DC conversion is not required, you can run straight AC trains.

 

In Japan the various AC frequencies were choosen based on what is available locally on the public network. Less densly populated areas benefit from AC as substation distances increase and overall costs are lower unless there is not enough traffic to justify the cost of maintenance. Costwise modern AC and DC stock is similar, except the transformer and one extra insulation on the high voltage part. (dc feedback requires the same transistor bridge)

 

The 25 kV AC system for shinksnsen was choosen as trials in Europe indicated that this was the practical limit with normal infrastructure. For example Hungary used 18-20 kV until the end of WW2 and upgraded to 25 kV during the reconstruction. Most locos were (and some still are) capable of running on 18/20/25 kV 18-50 hz.

 

Ps: about bemu-s: They were used in Europe in the past but turned out to be not as cheap as a single diesel with unpowered trailers. An interesting system was the ward-leonard ekectrics because they had a kers system, with a large flywheel mass to feed back to and run from when not under wire.

[Kabutoni]

AC is nice for high speed, but 1,067mm gauge isn't, so that was no reason for JNR to use AC. The highest regular speeds on Japanese regular tracks is 130kph, with the exception of the (now reduced to 110kph operations) Hoku-hoku line (160kph), which operates at 1500V. Mostly the practicality of it with the local grid and cold weather resistance.

 

Anyway, AC and DC stock might be similar in cost (in Europe?), but how about domestically produced AC/DC combined rolling stock? I'm sure these are far more expensive, as otherwise we wouldn't have seen different material for the Tsukuba Express; TX-1000s (DC) and TX-2000s (AC/DC), and as well more through services on the JR East Jyōban line.

 

As for battery operated BEMU (those that can operate on catenary, as well as batteries), how long ago are we talking about? I'm sure modern technology can justify the use of these, as there is a lot of experimenting going on with this in Japan, both at J-TREC and Kinki Sharyō, as well as the UK with the Class 379.

Edited April 13, 2015 by Toni Babelony

[kvp]

 

but how about domestically produced AC/DC combined rolling stock? I'm sure these are far more expensive, as otherwise we wouldn't have seen different material for the Tsukuba Express; TX-1000s (DC) and TX-2000s (AC/DC), and as well more through services on the JR East Jyōban line.

It all depends on the technology and politics. If you are doing it right, then an universal trainset costs roughly the same. Even a classic transformer/resistive set with series wound motors differs only in the extra insulation between the pantograph and the transformer and the transformer itself. The train line from the transformer to the motors is the same low voltage one both in AC and DC mode.

 

The Tsukuba Express is mostly a political case. The DC only sets have one more trailer, while the AC sets need the extra motor unit to compensate for the weight of the transformers. Apart from this, they are pretty much the same and the cost is very nearly the same, but this way the DC sets can't operate out of the DC region, meaning the train densities on the two parts of the line are determined by the power districts and not by actual traffic needs. To reflect this, the two types of sets have different seating arrangements. (weights:TX1000: 30.3+33.6+26.5+33.8+31.3+30.9=186.4, TX2000: 30.3+38.1+34.4+38.3+34.3+30.9=206.3, the difference is 19.9 or 9.6% and this contains the extra seats, the extra transformers and the two extra motor bogies with their control unit)

 

Generally speaking, today in case of overhead operation the form or electrification is only a matter of taste in an urban/suburban environment and AC is better only on long stretches of country running or with high power freight service due to lower infrastructure costs. Above certain power requirements, the only way to increase available traction power is to increase the voltage as currents can not be increased and high voltage usually means AC systems. High power allows high speeds or larger freight train weights. With a DC system either the weight of the freight train or the speed has to be decreased to stay within current limits. For a 20-25 kV AC system, the same wires can transfer 13-16 times the power of an 1.5 kV DC system with a slight cost increase at the isolators and a larger cost decrease at substation costs.

 

 

As for battery operated BEMU (those that can operate on catenary, as well as batteries), how long ago are we talking about? I'm sure modern technology can justify the use of these, as there is a lot of experimenting going on with this in Japan, both at J-TREC and Kinki Sharyō, as well as the UK with the Class 379.

1960-ies to 1970-ies. Battery technology got much better since then, but the up front costs of the batteries and the limited lifespan of modern batteries means diesel fuel can be cheaper for slower speed services or flatter terrain. There is a price point between batteries and fuel costs where one of them gets better than the other. This is different for every country and sometimes even for every line.

[Kabutoni]

Thanks for the explanation . That explains why in general AC operated regions are less developed than DC operated regions. Even in AC regions, dense commuter traffic is operated by DC powered trains (e.g. Senseki line, Sendai Subway and Nishitetsu). It's the voltage that determines the traffic volume and density in the end.

[Sacto1985]

I think given the finances of the Kantō Railway, even the higher density of traffic between Toride and Mitsukaido cannot justify the enormous initial expense of stringing up 20,000 V AC overhead wiring. What we may see are upgraded 2300, 2400 and 2500 Series DMU's with quieter, upgraded diesel-hydraulic systems for lower diesel emissions.

[kvp]

Since even the 11 to 16 car emu-s on the JR East lines around Tokyo can be run with 1.5 kV DC emu-s, there is really no need to use AC unless you are really so far off the grid, that the substration costs would be substantial. The higher voltage, lower current AC system is really good where you have really large freight trains and/or large uninhabited sections between two stations. Typical examples are the north japanese countryside with significant freight traffic and little population and the shinkansen network with few stops and routes that avoid civilisation as much as possible. DC is overall cheaper when you can spot smaller substations on every corner, since the weight and complexity reduction in onboard equipment offsets the costs of the more expensive infrastructure.

[Kabutoni]

I think given the finances of the Kantō Railway, even the higher density of traffic between Toride and Mitsukaido cannot justify the enormous initial expense of stringing up 20,000 V AC overhead wiring. What we may see are upgraded 2300, 2400 and 2500 Series DMU's with quieter, upgraded diesel-hydraulic systems for lower diesel emissions.

 

I wasn't referring to the Kantō Railway to upgrade with 20kV AC, but with 1500V DC for the Toride - Mizukaidō Depot section. AC would indeed be too expensive and wouldn't make sense. 1500V DC would be more viable, though would always require some form of rolling stock that can operate on both overhead and non-overhead rail. Maybe this would require too much investment in the end, but the development of new (and most importantly affordable) railway technologies could change this in the future. I'm eyeing the further development of BEMU and alternatives/derivatives for these applications.

 

The finances of the KR don't really have much to do with it, as the company is owned by Keisei Group, which in the end has the overhand on major decisions like these. Then again, Keisei Group doesn't really have a strong financial department that aims for profit, seems very conservative, and is slow in technological improvements. I mean, they just retired the 3300 types and have a bunch of old DMU running on the Kominato line (which recently have gained value as a tourist attraction).

[Sacto1985]

I wasn't referring to the Kantō Railway to upgrade with 20kV AC, but with 1500V DC for the Toride - Mizukaid Depot section. AC would indeed be too expensive and wouldn't make sense. 1500V DC would be more viable, though would always require some form of rolling stock that can operate on both overhead and non-overhead rail. Maybe this would require too much investment in the end, but the development of new (and most importantly affordable) railway technologies could change this in the future. I'm eyeing the further development of BEMU and alternatives/derivatives for these applications.

 

I still think going to 1,500 V DC from Toride to Mitsukaidō is not likely because by the time the line reaches Mitsukaidō, it may be too close to the Kakioka Geomagnetic Observatory anyway. Hence my suggestion that the DMU's currently in service on the Kantō Railway will be rebuilt with quieter, less-polluting diesel engines in the near future.

Edited April 14, 2015 by Sacto1985

[Kabutoni]

I still think going to 1,500 V DC from Toride to Mitsukaidō is not likely because by the time the line reaches Mitsukaidō, it may be too close to the Kakioka Geomagnetic Observatory anyway. Hence my suggestion that the DMU's currently in service on the Kantō Railway will be rebuilt with quieter, less-polluting diesel engines in the near future.

 

I see your point now. Mizukaidō is just in the 20km radius, but all 20kV is in the 30km radius, which makes my idea invalid. Shin-Moriya is more of a candidate for this AC/DC split point on the Jōsō line. That makes the whole conversion radically different! My bad... I think then as well that then the older DMU will receive updates sooner than any form of BEMU or whatever may be a viable alternative.

[westfalen]

What surprises me most out of this discussion is that the Kakioka Geomagnetic Observatory influenced the method of electrification of a large portion of the Japanese rail network, moving the observatory to a more remote area would have to be an easier option if that were the only reason.  I always thought it was just that 20kv AC was just the superior technology when the electrification of that area was started.

[kvp]

Actually having a good reason for different systems besides that the newer one is cheaper is a good thing. They could have choosen 2 wire DC overhead (trolleybus style) or insulated 3rd rail return (London underground) too. Both would solve the observatory problem for the few lines that go there, but AC was the cheapest and most effective

[Sacto1985]

In the end, it came down to this:

 

1. JNR adopted 20 kV 50 Hz north of Tokyo not only because of avoiding interference with the Kakioka Geomagnetic Laboratory, but also because of its ability to operate with far few electrical substations on per-kilometer basis and better cold-weather resistance, important in less-populated Tōhoku region.

 

2. The Hokuriku Main Line between Itoigawa and Tsuruga adopted 20 kV 60 Hz not only to get better the latest overhead power technology, but better winter weather resistance (the Hokuriku region of Japan is notorious for very high snowfalls in winter) and adopted 60 Hz to be compatible with local electrical power plants.

 

3. Former JNR lines on Kyushu adopted 20 kV 60 Hz because it was the best technology available in 1976. (By the way, JR Kyushu still has many DMU's because most of their lines outside of coastal areas are NOT electrified. That's why most of the JR Kyushu tourist-oriented trains are all DMU's, including Aso Boy and Yufuin no Mori.)