Hitachi interested in Istanbul monorail project

[bikkuri bahn]

The Japanese Hitachi group, which regretted missing out on the Marmaray Project, is counting down to what is being tentatively called the Havaray (monorail) tender. The Turkey general manager of the Japanese giant, Erman Akgün, said they are holding talks with potential local partners about the project and are highly confident about their bid.

 

http://www.dailysabah.com/money/2015/12/14/japans-hitachi-group-eyes-havaray-tender

 

*wish they hadn't used the stock picture of the mouseland monorail ><

[kvp]

http://www.citymetric.com/transport/istanbul-building-47km-monorail-network-deal-its-crippling-traffic-congestion-700

 

Some seem less enthusiastic about the monorail project.

[Mudkip Orange]

*wish they hadn't used the stock picture of the mouseland monorail ><

 

It's too damn small.

 

Disney asked Alweg for a "3/4 size" monorail and they built him that. Then Bombardier grabs the tech and suddenly you have 3/4 size in actual transit applications.

 

Hopefully Hitachi wins this one and goes in with full Japanese standard beam.

[kvp]

I'm more of a duorail (or birail) fan, even for elevated tracks. If it has to be special then i would rather choose the rubber wheeled guideway technology (ex. Yurikamome) from Mitsubishi as a technologically better solution.

 

For anything more serious, a heavy rail elevated line is much better, both in speed and capacity.

 

The 3/4 size is a matter of preference. Just look at the two London underground standards. They are both full scale.

[Mudkip Orange]

Monorail has a few advantages, albeit few take advantage of them.

 

---You can climb steeper grades with rubber tires, 10% is not unheard of.

 

---You can have *much* steeper superelevation, since the trains won't derail. The original Alweg test track in Germany in the 50's had upwards of 100pct super.

 

---You can have faster acceleration with rubber tires then with conventional traction steel wheels (although not necessarily faster than LIM).

 

---The elevated guideway can be *much* sleeker than the huge concrete bathtub required for heavy rail.

 

 

 

However, the Japanese have a cultural preference for low acceleration (the Kintetsu "rabbit car" is just a standard US LRV, and slower than a lot of midcentury traction equipment), and the Americans have insane safety regs that mandate things like continuous high platform walkways along the entire monorail length.

 

So in Japan you have a sleek guideway with slow trains and in the US you have a ridiculous guideway which could potentially see fast trains if US transit agencies weren't so ridiculously conservative.

[bikkuri bahn]

However, the Japanese have a cultural preference for low acceleration

 

Says who??

[kvp]

I think the rubber tired people movers used in japan have the same advantages (except high superelevation), while having a smaller vertical and larger horizontal profile than a monorail. Still the technology is cheaper and easier to integrate and even allows ground level running, which monorails are very bad at.

 

Personally if i had to design an elevated railway, i would choose longitudinal steel beams for carrying the rails, with flexible rubber/spring tie blocks and thin steel connecting (spacing) rods between the rails. (it would look like a ladder with thin steps) For power, a top contact third rail could be used, mounted on isolated outriggers next to one of the two main beams. For guidance, an air suspension based active bogie steering system could make sure to keep the flanges away from the rails even on sharper curves. (if it fails, you'll only get wheel squeak) The visual footprint of the track would be horizonally minimal (less than a monorail beam) and vertically almost zero (about 3 times the rail height) with option for ground and underground running and compatibility with existing systems. For double tracks, a T shape column could support the 4 steel beams of the 2 tracks. There is an option to add a steel grate between the two beams to provide a full length safe walkway that still lets the light through to the surface below.

 

The same layout described above could be used for a rubber tired people mover, with L shaped guideways replacing the rails on top of the longitudinal steel beams. This would allow a people mover to have a very light and simple guideway, while providing a steel suface for the tires to grab onto. Water and snow removal is automatic as neither of them could accumulate on the tracks. The only weak point of the design is the requirement for longitudinal steel beams between the columns. (this part of the design is actually already used by some railroad bridges)

Edited December 15, 2015 by kvp

[Mudkip Orange]

Says who??

 

Why do Japanese commuter trains have such laconic acceleration? It's clearly not technological limitations.

 

Hence, cultural. (Tradition/"It's always been that way" counts as cultural).

[bikkuri bahn]

_{Why do Japanese commuter trains have such laconic acceleration? It's clearly not technological limitations.}

 

Really?  Lets take a look at the Kintetsu Rabbit Car you referenced (btw, a model that was introduced way back in 1957).  It had an acceleration rate of 4.0km/h/s, which converted to m/s squared is 1.1112m/s²  Compared to the (very modern) DB Model 423 emu used in S-bahn services which has a rated acceleration of 1.0m/s², it's more or less equivalent.  I reckon the "laconic" acceleration, if really there, (which I have never really perceived, after riding thousands of km on the likes of Keikyu and Hanshin) has to do with station spacing, line curves, load factors, passenger comfort, line traffic, grade crossings, and braking distance, rather than some nebulous "cultural" factor.



　

[Mudkip Orange]

Ehh, I know very little of S-Bahn performance envelopes. So maybe it's less of a laconic thing on Japan's part and more of a US preference towards speedy accel (at least until we scrapped all of our indigenous systems and recast Frankfurt U-Bahn vehicles as "light rail").

 

Regardless, you could pull a *lot* more than 3.0mphps out of a monorail... if you wanted to.

[kvp]

Hungarian metro cars use 1.2 m/s^2 as top acceleration and 1.4 m/s^2 as emergency deceleration. The latter is enough to have some people fall even if they were holding on. You can't really use more without having everyone seated and belted which is not an option for an urban train. 1.1 m/s^2 service acceleration is pretty fast with standing passengers if you intend to leave them on their feet. This value was standard for most jnr era new performance trains.

 

So which us train could do more and what was its service pattern?

 

Ps: one ikarus-ganz 280 series articulated trolleybus prototype was equipped for 2m/s^2 acceleration on flat terrain while fully loaded (it was demoed in san francisco and designers were afraid it could'n start on a slope with full load). Later it was placed in service in Budapest. The motor had to be limited down to 1.3 m/s^2 as standing passengers regularly fell when it was accelerating with a light load on flat terrain. You can't really go much above 1.3 m/s2 and keep people on their feet. The emergency deceleration was kept at 5m/s^2 (full motor+air brakes, 18 km/h/s) which means it can stop on a dime and injure passegers (even sitting ones) if it's ever used.

 

Btw, relatively high acceleration is not really percived as one if the starting curve is smooth instead of jumping to full throttle. The same is true for high speed, if the ride is smooth you can't really feel it.