[smallspy]

The pole shoes are failing due to *over current* not voltage.

Actually, the pole shoes were failing because the last supplier changed the formulation of the carbon shoes. They were slightly longer wearing in dry conditions, but wore out in a fraction of the time in the wet. They've since gone back to the original formulation.

Surface area alone on the pants is multiples more than on pole types, plus the pickup area is swept laterally on pantos as the vehicle moves.

Not so. A CLRV shoe is a U-shaped carbon piece 2 1/2 inches long. The ALRV and Flexity shoes are 4 inches long, due to the higher draw from the bigger vehicles. In both cases, because it is U-shaped it will generally contact the wire on two of the three faces.

A pantograph will have two wipers 2 inches wide, which contact the wire (or contact rail) on one face only.

You can see this on train-lines more than trams where the catenary is actually zig-zagged laterally more than even the random amount from alternate side suspension guying. This also allows much greater heat dissipation from the contact resistance, which can be hot enough to effectively melt the carbon shoe in extreme cases of overcurrent. (in fact, the structure changes, it mostly vaporizes, but that's physics) .

The geometry of the wire in a pantograph-only application has nothing to do with heat disappation, at least not in terms of power draw. The wire will be set up to sweep back and forth across the vehicle in order to prevent grooves wearing into the pantograph carbons, and requiring them to be replaced early. This has already become a problem in Toronto, where they have not adjusted the geometry of the contact wire enough for pantograph use.

There's a multitude of advantages with pantos, not least the need to not 'switch' the pole shoe at junctions.

Absolutely there are. The ability to reverse without requiring additional supervision/help is another. They virtually eliminate dewiring incidents at specialwork, and their effects on shedules. And there is the ability to run lower clearances in situations such as tunnels when coupled with rigid contact rail for the OCS. Generally, maintenance of the OCS is cheaper as the whole of it can be simplified.

But there are also disadvantages as well, mainly upfront and replacement cost. A trolley pole costs $200 to replace, a shoe holder is about the same or less. A dumb pantograph starts at $10k, smart ones like the ones in Toronto can double that. The OCS must be more robust as a pantograph will exert more force on the overhead - again, this is an upfront cost, as maintenance in general should be less.

Dan
Toronto, Ont.

 

[DonValleyRainbow]

Actually, the pole shoes were failing because the last supplier changed the formulation of the carbon shoes. They were slightly longer wearing in dry conditions, but wore out in a fraction of the time in the wet. They've since gone back to the original formulation.

Isn't that what caused a power failure on the 510, and all intersecting east-west routes in the vicinity a while back?

 

[steveintoronto]

Not so. A CLRV shoe is a U-shaped carbon piece 2 1/2 inches long. The ALRV and Flexity shoes are 4 inches long, due to the higher draw from the bigger vehicles. In both cases, because it is U-shaped it will generally contact the wire on two of the three faces.

A pantograph will have two wipers 2 inches wide, which contact the wire (or contact rail) on one face only.

You confuse "contact area" with "surface area". It is a common mistake, but I digress.

The geometry of the wire in a pantograph-only application has nothing to do with heat disappation, at least not in terms of power draw. The wire will be set up to sweep back and forth across the vehicle in order to prevent grooves wearing into the pantograph carbons, and requiring them to be replaced early. This has already become a problem in Toronto, where they have not adjusted the geometry of the contact wire enough for pantograph use.

Geometry has everything to do with heat dissipation in a resistive contact, as well as the medium of dissipation. The conductor itself will act as a heat sink, but a considerable degree of cooling is to be had from atmospheric dissipation as overheated carbon shows. (Just follow the smoke to see the atmospheric heat transfer) Travel velocity aside displayed as wind speed, much of that dissipation will be convectional...and the greater the surface area, all things considered, the greater the rate of dissipation.

Think about that "back and forth" action you describe. And now think of the area made available for heat dissipation. The carbon, a poor thermal conductor, is cooled as a much larger surface area against the catenary, a very good thermal conductor/sink. Thermal failure is the number one cause of electrical and electronic components. Spread that carbon ribbon's area exposed to a dissipant, (the contact area) and you keep the entire device cooler.

I'll link an engineering paper later, must run right now.

 

[crs1026]

I am wondering, can any of the TTC subway lines (i.e. tunnel structures, station boxes, future rolling stock) utilize rigid contact rail for OCS?

I am not advocating this at all, but am simply trying to gain a clearer understanding of how low "lower clearance" rigid contact rail for OCS can be installed.

For example, could Relief Line South incorporate it without being materially redesigned?

Could Sheppard be retrofitted? Could Line 2? Could Line 1?

Rigid contact rail mostly reduces the distance between the catenary wire and the top of the supports above it. That's what is meant by "low profile".

It may also partly reduce the minimum design distance between the carbody and the catenary, by removing any need for an allowance for sag in the catenary.(the catenary wire is kept at tension, but sag happens.....). So the contact rail may be closer to the carbody than OCS.

However - there is a minimum distance that the catenary wire must be kept from the carbody to prevent any risk of arcing. The pantograph usually sits on insulators so the minimum vertical clearance that it needs is not trivial.

For our existing lines, there is an awful lot of box concrete construction which leaves little or no room above the carbody for a pantograph, even with a rigid contact rail. All it takes is one short segment of box construction to constrain the entire line. I doubt it would be affordable to change that. The interior roofline in the TR's is low enough already ;-)

For new lines, one could design a higher profile tunnel that allows the necessary vertical clearance consistently from end to end - but that would add cost significantly. Is it possible? Yes. With lots of money.

- Paul

 

[crs1026]

Switching from catenary to newswire - 4503 arrived Toronto, delivery imminent. 4504 ready to ship at the Bay.

- Paul

 

[smallspy]

Geometry has everything to do with heat dissipation in a resistive contact, as well as the medium of dissipation. The conductor itself will act as a heat sink, but a considerable degree of cooling is to be had from atmospheric dissipation as overheated carbon shows. (Just follow the smoke to see the atmospheric heat transfer) Travel velocity aside displayed as wind speed, much of that dissipation will be convectional...and the greater the surface area, all things considered, the greater the rate of dissipation.

Think about that "back and forth" action you describe. And now think of the area made available for heat dissipation. The carbon, a poor thermal conductor, is cooled as a much larger surface area against the catenary, a very good thermal conductor/sink. Thermal failure is the number one cause of electrical and electronic components. Spread that carbon ribbon's area exposed to a dissipant, (the contact area) and you keep the entire device cooler.

While there's no doubt that staggering the overhead wire does help with heat dissipation, it is not it's primary raison d'être. Again, it is to prevent groove formation.

Dan
Toronto, Ont.

 

[TOareaFan]

I think the folks at BBD are getting their confidence back

 

[Andy T]

Kingston has completed their first car
https://twitter.com/bombardierrail/status/1047579782844751872?s=21

 

[SaugeenJunction]

Kingston has completed their first car
https://twitter.com/bombardierrail/status/1047579782844751872?s=21

How is this thread gonna track which cars are en route now! In seriousness, glad to see it.

 

[thettctransitfanatic]

Guys, don't forget that effective this Sunday, the 514 will cease to exist, and the new 504A Dundas West Station--Distllery will be fully accessible with Flexities, and the plans for the 504B Broadview Station-Dufferin are that, I think, a mix of CLRV'S and Flexities.

 

[crs1026]

How is this thread gonna track which cars are en route now! In seriousness, glad to see it.

I wonder how the numbering will be managed.... will the Kingston cars have their own block of numbers, say 4560 and up?

A gold star to whoever is first to notice an external spotting difference between the Thunder Bay cars and the Kingston flavour. We rivet counters obsess about that kind of detail!

- Paul

 

[Steve X]

In the future I have a sense one line's production would have a higher reliability than the other. Even with the TRs, they are still having reliability problems. Their MDBF is like a roller coaster. I don't know will they ever achieve higher reliability at this rate.

 

[raptor]

I wonder how the numbering will be managed.... will the Kingston cars have their own block of numbers, say 4560 and up?

A gold star to whoever is first to notice an external spotting difference between the Thunder Bay cars and the Kingston flavour. We rivet counters obsess about that kind of detail!

- Paul

Aren't the vehicle numbered once they arrive in Toronto?

 

[crs1026]

Aren't the vehicle numbered once they arrive in Toronto?

Nope.

We discussed this a while back - They are likely numbered on paper when each frame is first laid down, and Bombardier applies the final numbers before shipping the cars.

- Paul

 

[DSC]

Aren't the vehicle numbered once they arrive in Toronto?

No, lots of photos of vehicles en route here with numbers clearly showing.