Sapporo's subway car's pantographs?

[trainsforever8]

Hey guys, I've always found the idea of the fact that rubber-wheeled trains could have pantographs unusual since I'm from Montreal, our subway trains take electricity from the guide rail also used by the guiding wheels.

 

I've been searching for pics of Sapporo's subway cars where you could clearly see their pantographs, I wanted to see if they looked the same as any other electric train or if they were different.

 

I'm aware that the Namboku line uses the third rail which leads me to wonder, why didn't they keep the same technology for the Tozai and Toho lines?

 

Would anyone happen to know where I could find the trains' pantographs' pictures? 

 

Thank you.

[Suica]

I found these: 

 

 

The panto is also shown in this video http://youtu.be/DXZJtzX1RUY

Edited February 20, 2016 by Suica

[trainsforever8]

Thank you so much! 

 

Is it me or are they smaller than usual pantographs?

[kvp]

Some japanese lines use smaller ones when there are lots of tunnel running with low wires and the wire is never raised high. Some older sets in the past had to be modified to sunk the large pantos into the roof but then they invented the small ones several decades ago.

 

Imho if there is open air running with lots of accumulated snow on the tracks, then overhead power is a bit better than 3rd rail.

[SuRoNeFu 25-501]

Thank you so much! 

 

Is it me or are they smaller than usual pantographs?

The pantograph is built in smaller dimensions, due to the very low clearance between the train's roof and the tunnel's ceiling (where the overhead lines are being hung above the track). Note that the majority of subway lines in Japan that uses overhead line system are employing rigid-type overhead line, including lines that completely built underground (without any thru-services to conventional railway lines). Even those being built with linear propulsion like Oedo Line, Nagahori-Tsurumi-Ryokuchi Line, etc were constructed with rigid overhead lines (albeit with lower clearance)...

[trainsforever8]

Thank you for the information everyone! I guess it makes sense that the pantographs are built smaller. It's too bad rubber wheeled subways can't go outside if there's snow. Here in Montreal, subway extensions are considered expensive because we can't make the trains go outside so it always has to be a tunnel. I think rubber wheeled metros were the "smart" choice back in the 60's as it had an advantage to steel wheeled trains, however now I think that if ever Montreal felt the need to build a new metro line, it would have to be steel-wheeled.

[Socimi]

Why it should be in a tunnel?

 

Marseille's metro has also overground lines, even if it's evidently a rubber-tyred metro.

 

 

So does Paris or Santiago Del Chile

[Suica]

A lot of rubber-tyred metro lines have overground bits.

Hiroshima's Astram line is mostly overground. So are most light metros used at airports.

[kvp]

Actually rubber tires are better in snow as they have better traction. This and the ability to handle high grades were two reasons for using rubber wheels in sapporo.

 

Btw: Keeping an overhead wire snow free is easier than a 3rd rail, unless it's side contact and fairly above track level.

[Suica]

Btw: Keeping an overhead wire snow free is easier than a 3rd rail, unless it's side contact and fairly above track level.

 

I don't know about other countries, but bottom-contact third rails are pretty common in Germany. They don't cause much of a problem. (It's mostly heater defects that disable our trains. :P)

 

But then again, Sapporo has much more snow during winter than most German cities.

Edited February 20, 2016 by Suica

[trainsforever8]

Why it should be in a tunnel?

 

Marseille's metro has also overground lines, even if it's evidently a rubber-tyred metro.

 

 

So does Paris or Santiago Del Chile

 

Yes, however those cities don't have the types of winters that we have in Montreal. Our trains are simply not designed to go outside, let alone to go in snow. Whenever there's snow in Paris, the rubber-wheeled lines have technical problems. Even if tires provide better traction speed, they don't have this advantage when it comes to winter, feasibility studies have previously been made regarding this issue.

[kvp]

 

Whenever there's snow in Paris, the rubber-wheeled lines have technical problems.

That's actually the result of some braindead maintenance management. The rubber tires have to be swapped for winter tires or if they are all weather (from the smell in the summer they seem to be), the pressure has to be lowered in them, so they have a larger traction surface. The metal backup wheels would keep the trains on the tracks anyway, so low pressure is dangerous. (actually, completly removing the rubber tires would work too, very much like replacing the bogies with conventional ones as these lines still have metal rails)

 

For the 3rd rail, bottom contact is also good against frozen on snow and ice, but they tend to be mounted rather low, so snowdrifts tend to accumulate between the ground and the 3rd rail and if frozen over, that could jam or actually break off the pickups. High mounted 3rd rail is better as the snow can't accumulate easily. The highest mounted 3rd rail is actually the overthead third rail, in use for ungerground railways since the late 19th century. (the first mass transit line to use it was the Budapest underground) So in case the snow reaches the overhead wire, bad power pickup is long not the biggest problem.

 

I think the best winter safe electric traction solution right now is the new elevated hokkaido shinkansen line, with self cleaning tracks and overhead ac power. Imho, a proper rubber wheeled line running on a concrete guideway with side contact pickups or overhead power is also acceptable for low speed, high gradient running.

[SuRoNeFu 25-501]

Keeping an overhead wire snow free is easier than a 3rd rail, unless it's side contact and fairly above track level.

In fact, removing the snow icicles from the contact wires are much easier, since you can use the second pantograph of a train (if it has two pantographs installed on the roof) to remove them. And even someone can use an old single-car EMU to "kick" them off from the contact wire, either running single or coupled to an revenue-earning train