Electrical Engineering - Re: "European" catenary on the North-East Corridor (USA)

Author

Re: "European" catenary on the North-East Corridor (USA)

Robert Hubbard

2008-03-26, 5:25 pm

On Mar 21, 10:10=A0am, Alan McKenney <alan_mckenn...@yahoo.com> wrote:
> About 10 years or so ago, the catenary on at least
> some parts of the North-East Corridor were replaced
> with what was touted as "Eurpean-style" catenary.
> It was never explained exactly what was meant by that,
> but it was claimed that the "European" catenary was
> much better than the old.
>
> I recall from my years in Europe that one of the most
> distinctive things about the catenary there was that
> the wire was tensioned using weights -- the wire
> would be run out to a pulley, with weights hanging off
> the larger diameter wheel to apply torque and thus tension.
>
> This meant that the tension would remain constant
> as the wire expanded and contracted.
>
> By contrast, in the Northeast (USA), the contact wire is
> just tied off to posts at either end. =A0 As far as I have
> been able to tell in my occasional trips around here,
> that's still the case.
>
> Am I just not seeing the weights? =A0If they're not there,
> what exactly is "European" about the new catenary?
> And, given the number of reports of catenary problems
> when it's too cold or too hot, why aren't weights used
> in the USA?

I'm somewhat curious about the electric circuitry feeding the
catenary. The "new" section has, in addition to the catenary and
contact wires, two insulated feed lines (one on each side) plus
grounded returns. Nice and simple. In contrast, between NYC and New
Haven, there are (old) pylons carrying multiple conductors for the
catenaries plus some higher voltage circuits. For example, at the New
Rochelle station there seem to be 15 12 kV conductors for track power
(plus the catenaries for 4 tracks) there. Why so many?

Also, since the trains are large single phase loads, how do they try
to balance the railroad as a whole over the three phase supply?

Where is the switchover between the 25 Hz power to the south and 60 Hz
power? Right at Penn Station?

Beachcomber

2008-03-27, 1:25 pm

On Wed, 26 Mar 2008 14:00:51 -0700 (PDT), Robert Hubbard
<roberthubbard0@yahoo.com> wrote:

>On Mar 21, 10:10=A0am, Alan McKenney <alan_mckenn...@yahoo.com> wrote:
>

Portland Oregon has the variable weight system for it's Max Train
catenaries. Not surprisingly, these were originally designed by a
European contractor, I believe.

At certain pylons, there are tensioning weights that can be added or
subtracted, as necessary. The system is very similar to the systems I
recall seeing in France.

Stephen Sprunk

2008-03-27, 1:25 pm

"Beachcomber" <invalid@notreal.none> wrote in message
news:47ebb808.3537671@news.verizon.net...
> Portland Oregon has the variable weight system for it's Max Train
> catenaries. Not surprisingly, these were originally designed by a
> European contractor, I believe.
>
> At certain pylons, there are tensioning weights that can be added or
> subtracted, as necessary. The system is very similar to the systems I
> recall seeing in France.

All of the new LRT systems in the US I've seen have constant-tension
catenary in sections where they have exclusive ROW. Many use simple trolley
wire (variable tension with just a contact wire, no catenary wire) for
street-running sections, though.

S

--
Stephen Sprunk "God does not play dice." --Albert Einstein
CCIE #3723 "God is an inveterate gambler, and He throws the
K5SSS dice at every possible opportunity." --Stephen Hawking

Adam H. Kerman

2008-03-27, 1:25 pm

Beachcomber <invalid@notreal.none> wrote:

>Portland Oregon has the variable weight system for it's Max Train catenaries.

What is a variable weight system and what advantage could it have over a
simple pulley with a fixed weight?

Beachcomber

2008-03-27, 5:25 pm

On Thu, 27 Mar 2008 11:23:01 -0500, "Adam H. Kerman" <ahk@chinet.com>
wrote:

>Beachcomber <invalid@notreal.none> wrote:
>
>
>What is a variable weight system and what advantage could it have over a
>simple pulley with a fixed weight?

Some of the pylons I've seen in Portland have multiple weights that
are semi-enclosed in a metal box. There is a sort of cotter pin
arrangement that selects how many weights are actually providing
tension.

My guess would be that the tension on the long spans might vary over
time (as the wire is stretched). Also there might be seasonal
variations throughout the year due to temperature (and conductor
sag?).

I'm no expert though. Perhaps someone with specific knowlege of this
setup can provide more insight.

Beachcomber

2008-03-27, 5:25 pm

>My guess would be that the tension on the long spans might vary over
>time (as the wire is stretched). Also there might be seasonal
>variations throughout the year due to temperature (and conductor
>sag?).
>
>I'm no expert though. Perhaps someone with specific knowlege of this
>setup can provide more insight.
>
>
.... Also, It could be that once a specific weight is set for a
particular span... It pretty much stays that way...

The multiple weights could just be for ease in setting a specific
level of tension during construction.

Richard Mlynarik

2008-03-27, 8:25 pm

Beachcomber wrote, On 2008-03-27 14:58:
> ... Also, It could be that once a specific weight is set for a
> particular span... It pretty much stays that way...
>
> The multiple weights could just be for ease in setting a specific
> level of tension during construction.

Correct.

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