Kinki Sharyo introduces prototype of hybrid EMU- "Smart BEST"

[bikkuri bahn]

@Kinki Sharyo in Higashi Osaka last Thursday, Oct. 11.

 

The unit runs off a battery on non-electrified portions of track.  A small diesel generator is used to "top off" the battery as it is discharged. The cab and interior is very much in the JR West style.  Apparently it will test on JR West lines in the near future.

[keitaro]

nice i'm a big supported of hybrid trains,

 

So does this use the battery for acceleration from the platform to under electrified lines or they don't say?

 

I ownder how heavy those batteries are.

[KenS]

There's no pantograph, so this looks like a DMU replacement.  They could pre-charge the battery overnight to save fuel, and I'm sure they're recovering power when braking, but most of the power would ultimately come from the diesel.  And the display shown in the video suggests the generator could power the motors directly, although they don't appear to show it doing that.

 

Like a yard switcher, a stop-and-go passenger DMU seems like a really good application for a hybrid power design.  Lots of braking that wastes power in an ordinary diesel, and lots of coasting between stations where the engine  is doing very little. A small engine with battery for stored power and higher acceleration power makes lots of sense.

 

The batteries probably are quite heavy, but you save some of that in a lighter engine block and less fuel storage. And trains need to be reasonably heavy for traction, so there's probably excess steel in a DMU frame they can partly remove to offset additional battery weight.

[Densha]

For a completely non-electrified line I think this would probably be the best solution, but there are some lines where a long part of the route has catenary and it would make more sense to have a pantograph available as well. For both use and storage of the electricity. I've yet to see any train or plans like that though.

[Sacto1985]

There's one place where this passenger trainset may have a good use: the JR West San'in Main Line in Shimane and western Tottori Prefectures, where there are both non-electrified and electrified portions of the main line. (The electrified portion is primarily for the Yakumo limited express train that travels on the San'in Main Line between Hokidaisen and Izumoshi stations after coming into Shimane Precture through the Hakubi Line).

[miyakoji]

For a completely non-electrified line I think this would probably be the best solution, but there are some lines where a long part of the route has catenary and it would make more sense to have a pantograph available as well. For both use and storage of the electricity. I've yet to see any train or plans like that though.

that's an interesting point Densha.  I wonder how many regular diesel services there are that run for significant distances under wire.  Sacto has a pretty good example where the Sanin Main Line is electrified for services coming off the Hakubi Line.  JR Central's Mie and Hida run under wire for some distance, but I'm not sure I'd call it significant considering the total distance of the service.  The third service (that I know of) where this applies is the rapid to Taketoyo, but they're electrifying that line. JR Shikoku probably has some examples, but again, I don't know how many of them run under wire for a significant distance.  It would have to be something coming off the Yosan Line, I think the rest of their territory is not electrified.  Honestly I'm surprised Japanese railways have the amount of non-electrified track that they do.  They've got passengers, they've got EMUs surplussed by new stock, DMUs seem to be built in small quantities which I expect would make them more expensive, and diesel fuel is not going to get cheaper.

[KenS]

DC electrification needs substations every 2km or so.  It's not a very efficient method for long rural lines, unless there's a lot of use so the savings pay off the capital needed to build that infrastructure in a reasonable period.

[Densha]

This one is another example of a local service I found:

http://en.wikipedia.org/wiki/Nanao_Line

But again, it's just about half a kilometer that is confirmed electrified according to wiki. What could be more interesting IMO are through services for lines that are now cut up in a electrified and non-electrified section.

 

JR Shikoku is another story (so far I understand correctly). If I have to believe wikipedia, the Shiokaze through DMU express services from Okayama to Uwajima (a total of almost 300 km) are running on electrified track from Okayama to Iyoshi (206 km) and under non-electrified track for the last ~100 kilometer. Some services don't go further than Matsuyama (a few stops before Iyoshi) and are done by EMUs.

After browsing for a while I think this is just one of the few examples of JR Shikoku.

http://en.wikipedia.org/wiki/Shiokaze_%28train%29

http://en.wikipedia.org/wiki/Yosan_Line

 

Please correct me if I'm wrong.

[Mudkip Orange]

Chevy Volt on rails. I like it.

[Nick_Burman]

DC electrification needs substations every 2km or so. 

 

Only 600/750V DC lines use this kind of spacing. 1500V DC substations can be spaced much farther apart, up to 20km if not longer if you add intermediate booster feeders.

 

 

Cheers NB

[miyakoji]

DC electrification needs substations every 2km or so. 

 

Only 600/750V DC lines use this kind of spacing. 1500V DC substations can be spaced much farther apart, up to 20km if not longer if you add intermediate booster feeders.

 

 

Cheers NB

I've read before that DC needs more substations, but I didn't know that the number varied with voltage.  But how does this compare to 20 or 25kV AC?

[Nick_Burman]

DC electrification needs substations every 2km or so. 

 

Only 600/750V DC lines use this kind of spacing. 1500V DC substations can be spaced much farther apart, up to 20km if not longer if you add intermediate booster feeders.

 

 

Cheers NB

I've read before that DC needs more substations, but I didn't know that the number varied with voltage.  But how does this compare to 20 or 25kV AC?

 

The number not only varies with voltage, but also with the volume of traffic you want to pass. The more traffic there is, the more it requires power and the closer you need to space your substations (plus the more powerful your substation fittings need to be); conversely, lines with low traffic can get by with substations at long spacings. In the case of 25Kv lines, anything between 30Km and 100Km (with intermediate booster feeders) is possible - BC Rail's Tumbler Ridge line was 82 miles long and ran off one substation, plus booster feeders.

 

Cheers NB

[KenS]

Nick, are you sure about that?  I've traced some of the Tokyo JRE 1500V lines, and its pretty easy to find a substation every 2 km along them.  Perhaps it's just the amount of power needed, but DC at any usable voltage has really poor distance transmission due to high currents.  That's why AC transmission lines use voltages of tens or hundreds of thousands of volts (higher voltage = lower current = longer distance with less loss).  And you can't change AC (for transmission) to DC (for use) without some kind of equipment you'd find in the substation (typically a transformer/rectifier set).

 

The original DC vs AC for transmission battle was fought between Edison and Westinghouse back in the 1880s due to that, and AC won because of the inefficiency of DC transmission (see Wikipedia's War of Currents entry).

 

Now with higher traffic, you would need closer substations due to the amount of current passing through a single set of wires (which is limited by wire size), but even if there's only one train, if you try to push DC 20 km, you're throwing a lot of it away in heat loss, and while 750 is worse than 1500 (by about 2x I think), neither is close to 12,000 volts, which is a typical "across town" transmission voltage.

 

I don't recall offhand where I heard the 2 km figure, but I heard it in the context of Japanese trains before I went looking for substations, and found them every 2 km.

 

BTW, back on the original topic of the hybrid EMU, JRE's research group has a page describing their work/plans on hybrid railcars.

[Nick_Burman]

Nick, are you sure about that?  I've traced some of the Tokyo JRE 1500V lines, and its pretty easy to find a substation every 2 km along them.  Perhaps it's just the amount of power needed, but DC at any usable voltage has really poor distance transmission due to high currents.  That's why AC transmission lines use voltages of tens or hundreds of thousands of volts (higher voltage = lower current = longer distance with less loss).  And you can't change AC (for transmission) to DC (for use) without some kind of equipment you'd find in the substation (typically a transformer/rectifier set).

 

The original DC vs AC for transmission battle was fought between Edison and Westinghouse back in the 1880s due to that, and AC won because of the inefficiency of DC transmission (see Wikipedia's War of Currents entry).

 

Now with higher traffic, you would need closer substations due to the amount of current passing through a single set of wires (which is limited by wire size), but even if there's only one train, if you try to push DC 20 km, you're throwing a lot of it away in heat loss, and while 750 is worse than 1500 (by about 2x I think), neither is close to 12,000 volts, which is a typical "across town" transmission voltage.

 

I don't recall offhand where I heard the 2 km figure, but I heard it in the context of Japanese trains before I went looking for substations, and found them every 2 km.

 

BTW, back on the original topic of the hybrid EMU, JRE's research group has a page describing their work/plans on hybrid railcars.

 

 

Tokyo is an extreme case - with so many trains moving about, power needs will obviously be high so closely spaced substations are a must. The same must apply for some main lines out of Tokyo. Conversely, some rural lines with light traffic (say, for instance, the Iida Line - I don't know if it is true) or lesser private railways can easily live with a substation every dozen or couple of dozen km - if not a substation for the whole length of the line. To ease power loss the power block would receive a DC booster (at line voltage) about 1/3 of the way to the next substation, with this substation sending another booster to a point 2/3rds of the way. Of course, such set-ups can vary from line to line and railway to railway - geography, operating practices and traffic dictate specific needs. Here in Brazil the Campos do Jordao Railway (30-odd km, 1500V DC) gets by with one substation (set up midway along the line) + line voltage boosters. However, their traffic is very sparse and composed mainly of single railcars with the occasional railcar + trailer, so this system suffices for its needs. There is one glitch though - the railway suffers a lot of power loss through ground seepage due the state of the OHW system, which dates from the electrification of the line in the 1920's.

 

Semiconductor technology has made high voltage DC power transmission possible - for instance, one of the high voltage lines connecting Itaipu Dam with the Greater Sao Paulo area is a DC line. And go figure it, it's reckoned to be more efficient that the paralleling AC lines!

 

Cheers NB

[KenS]

Thanks. I'd wondered if anyone was doing high-voltage DC transmission now that we had the technology to do solid-state DC-DC voltage conversions, but hadn't come across any mention of it. 

 

I've read of pole-mounted booster transformers on AC lines, but it sounds like you're saying that these are also used on DC lines, with some kind of AC-DC or DC-DC voltage transforming equipment.  Can you say more about that, or point to a reference?

[brill27mcb]

On trolley lines a century ago, 10 miles (16 km) was a reasonable spacing between 600 VDC substations. I have period books that state this.

 

These days, of course,  we use a lot more power for heavier cars with better acceleration, air conditioning, and so on.

 

Rich K.

[KenS]

I did a bit of digging about, and turned up a Japan Railway and Transport Review article from 1998 on Railway Electric Power Feeding Systems (download PDF from this page). It's very interesting reading (if a bit too technical for me in places).

 

It mentions Booster Transformer (BT) systems, but from the text and diagrams these appear to apply only to AC lines, both conventional and originally Shinkansen, although the Shinkansen appear to have moved on the use of Auto-Transformer (AT) systems.

 

With BT systems, spacing of substations is 30 to 50 km for conventional (AC) lines.  With AT systems, spacing is 90 to 110 km for conventional lines and 20 to 60 km for Shinkansen. Shinkansen in the Tokyo area are described as using a different "coaxial" system, with spacing of substations every 10 km but no additional transformers. The substation is where very high transmission voltage (tens to hundreds of kV) gets stepped down to either line voltage or the voltage used by lineside boosters or autotransformers (tens of kV).

 

However, with the Shinkansen AT system, a 60kV to 30kV auto-transformer is required every 10km, and this is big enough to require what I'd call a substation facility (fenced gravel field with concrete pads; there's a photo in the article).  AT systems are also used for non-Shinkansen AC systems, but there was no information on the size of the transformer (they're 44kV to 22 kV transformers, so they're not small). With the BT system, the BT is placed "every 4 km", but it's not clear how large these would be; they apparently operate on 22kV voltages, but details are not provided.

 

Of conventional (non-BT by implication) DC systems, it says that "The distance between substations is about 5 km on metropolitan trunk lines, and 10 km on other lines."

[Sacto1985]

By the way, YouTube contributor nimo5 caught the Smart BEST prototype testing at Yonago Station just east of Matsue:

 

 

It appears my hunch was correct: they are probably looking at running this new trainset in production form on the San'in Main Line.

[miyakoji]

It could also be a good place to test them.  JR West has got maintenance shops there, and there's also room in the timetables to run them.  JR East is getting hybrid DMUs (HMUs?), maybe JRW wants them too.  JRW has quite a few DMUs around of various ages.  KIHA40s are at least 30 years old, KIHA120s are 15-21, KIHA126s are about 10, and the KIHA127s are only 4.  Some KIHA40s, of which there are still a lot, and maybe some of the seemingly lightly-built KIHA120s, will need replacement at some point in the foreseeable future, something based on this technology could be a good candidate.

[Sacto1985]

If Kinki Sharyo--who built this test trainset--incorporates pantographs into the trainset, then it would be perfect for operating on the San'in Main Line in Shimane and western Tottori prefectures and on the JR Shikoku Yosan line--rail lines that are not completely electrified. That way, the batteries can be charged using overhead wiring and they can travel on non-electrified portions of the line with a lot less running of the diesel engine.

[miyakoji]

No details, but this hybrid was taken back to the Kinki factory on the 12th.

 

http://railf.jp/news/2012/12/14/150000.html