Clank wrote:
Anna Noyd-Dryver Wrote in message:
Clank wrote: On the other hand... What's
wrong with trolley poles? They seem pretty reliable even in inclement
weather*. On a tram, where the poles wouldn't even have to deal with
the vehicle moving all over the road to overtake etc., I don't see any
reason why they should be particularly problematic. More prone to
dewirement, particularly as speed increases. Junction'pointwork' more
complicated and prone to failure. More maintenancerequired too, I think.
Need changing over at every terminus. Anna Noyd-Dryver

With all due respect - and I use that in its extremely unusual totally
sincere sense - are all those true, or are they just "received wisdom"
used to back-justify the UK's resistance to trolleys (and indeed trams)?


My post was based on my knowledge and experience of UK heritage tramway
operations, my knowledge of UK heritage tramway maintenance, and of OLE
equipment fitted; and finally the fact that non-heritage tramways using
trolleypoles rather than pantographs are a tiny minority if indeed any
exist at all.

The junction pointwork here is generally lightweight and simple, and even
if it wasn't how much trouble would it be; an awful lot (crossovers etc.)
can be done entirely passively, so given that a system like Croydon
Tramlink would require all of about 3* sets of points how much overhead
(no pun intended) do they really add?

* Approximately, and I've not looked in detail, but pretty sure the
central loop, and all the various sets of track points for the single
line sections on the Wimbledon branch could be handled by passive trolley
OHL with no points required - so the only places you need actual points
in the OHL are Sandilands, Arena & Church Street.


Even in the trailing direction, a frog casting in the OLE presents a
disruption to smooth passage of the trolley head, and extra complication to
the layout of wiring and supporting wires, compared to having two plain
wires which don’t even have to touch.

Taking Croydon specifically, with a little imagination you could get away
without a facing frog in the OLE leaving any of the termini or the single
line sections, however you’d need them for entering the three double-track
termini, at each end of the depot (and vastly increased complication within
the depot), at Church Street, Sandilands, Arena and each end of East
Croydon.

Plus, of course, you lose flexibility for any unusual working, wrong line
moves etc, without added operational complication.


Anna Noyd-Dryver

Marland wrote:
Anna Noyd-Dryver wrote:
Marland wrote:
Anna Noyd-Dryver wrote:
Marland wrote:
bob wrote:
Graeme Wall wrote:
On 08/02/2019 10:58, Bevan Price wrote:
On 08/02/19 4:14, Recliner wrote:
The DfT remains consistent in its dislike of OHLE

https://www.thetimes.co.uk/article/battery-powered-trams-to-beat-congestion-pzz3p9jk3?shareToken=d7efc8230f20d995b8ea4bff5daae 175





As usual, the incompetent DfT only thinks about short term costs of
initial construction, not the long term running / operating costs.

Batteries have a finite life. You can recharge them, but they eventually
deteriorate, hold less charge, and have to be replaced - and they are
not cheap to replace.

Moreover, you use additional energy to convey the weight of the
batteries on every journey, instead of getting energy from fixed
overhead wires to move a vehicle that is lighter due to the absence of
batteries.

And before anyone suggests fuel cells, they also have finite lives, and
to function, they often rely on the presence of rare, expensive,
precious metals (platinum, palladium, rhodium, etc.)


Though once you've done the difficult bit of the infrastructure,
actually getting the tracks in the road, adding OLE later is a much
simpler engineering task.

It is provided you’ve done the work to properly isolate the track return
current to prevent electrolytic corrosion problems. If not, it probably
means ripping the whole lot up again.


Or use twin conductors like a trolley bus.



That would necessitate use of trolley poles, where pantographs are the
current standard fitment for new tramways.

I suppose you could have twin pantographs as fitted for 3-phase on certain
mountain railways, though you might get polarity issues on single track
sections, plus I suspect the OLE then needs to be aligned more accurately,
thus making it more intrusive.


What polarity issues would that be? Trolley buses frequently moved poles
over to the opposite set to get around an obstruction or damaged section.
DC traction motors as used in trams ,trolleys and trains have the the field
windings made from coils and are not polarity sensitive, its only on small
DC motors with permanent magnets like on model trains etc that reversing
the polarity will make the motor rotate in a different direction.

Though in the unlikely event of such an installation happening would trams
still be using DC motors nowadays?
Or like most trains electronic gubbins that can be fed all sorts of things
then send it to a AC 3phase motors.


AIUI trolleybuses are designed with both the positive and negative traction
circuits fully isolated from the vehicle. Trams OTOH have the negative
side, ie rails, connected to to the vehicle underframe and body frame ie
everything is earthed. The two-wire tram would therefore need a
non-standard wiring loom etc.

AFAIK modern trams have separate traction wiring for both polarities though
as you say they will eventually arrive at the same earth point, but there
would not be much complication if the the cable to that was connected to a
second pole and wire, just not at the same time , any idea how London’s
conduit trams were wired? The conduit supply was not electrical different
from a two wire supply except the wires have become protected live rails,
the track was not used as the return . It must have taken some good
planning on such a large system to ensure no tram could end up with the
plough turned around, and you have the added complication that after
dropping the ploughs and going to overhead on some routes then the chassis
and wheel return would then be used. Did those trams have a switch that had
to be operated to go from plough return or track?

London conduit trams have a switch on the platform at one end to change
between pole and conduit (or between each pole and conduit if two separate
poles are fitted). I’ll have to enquire about how they’re wired and what
exactly is switched; however polarity shouldn’t be an issue as the London
conduit system didn’t have any single track AFAIK. The left/right contacts
on the below-surface part of the plough become front/rear contacts where
the plough can slide sideways across the car.


Anna Noyd-Dryver

On Sat, 9 Feb 2019 18:57:48 +0200 (GMT+02:00)
Clank wrote:
Anna Noyd-Dryver Wrote in message:
Clank wrote: Anna Noyd-Dryver Anna@noyd-dryver=
..com Wrote in message: Clank wrote: On the =
other hand... What's wrong with trolley poles? They seem pretty reliab=
le even in inclement weather*. On a tram, where the poles wouldn't even=

Please introduce your news client to the concept of newlines.

wrote:
On Sat, 9 Feb 2019 18:57:48 +0200 (GMT+02:00)
Clank wrote:
Anna Noyd-Dryver Wrote in message:
Clank wrote: Anna Noyd-Dryver Anna@noyd-dryver=
..com Wrote in message: Clank wrote: On the =
other hand... What's wrong with trolley poles? They seem pretty reliab=
le even in inclement weather*. On a tram, where the poles wouldn't even=

Please introduce your news client to the concept of newlines.



Clank’s quoting of my recent posts has been rather odd. It it a problem
with my Usenet reader or his?


Anna Noyd-Dryver

Anna Noyd-Dryver Wrote in message:
Clank wrote: Anna Noyd-Dryver Wrote in message: Clank wrote: On the other hand... What's wrong with trolley poles? They seem pretty reliable even in inclement weather*. On a tram, where the poles wouldn't even have to deal with the vehicle moving all over the road to overtake etc., I don't see any reason why they should be particularly problematic. More prone to dewirement, particularly as speed increases. Junction'pointwork' more complicated and prone to failure. More maintenancerequired too, I think. Need changing over at every terminus. Anna Noyd-Dryver With all due respect - and I use that in its extremely unusual totally sincere sense - are all those true, or are they just "received wisdom" used to back-justify the UK's resistance to trolleys (and indeed trams)? My post was based on my knowledge and experience of UK heritage tramwayoperations, my knowledge of UK heritage tramway maintenance, and of OLEequipment fitted;

Genuine question - do you think heritage operations are representative of modern equipment? Do you use modern OHLE in fact? (As I say, genuine question - not clear to me if a heritage tramway is all about the rolling stock or if you also try to keep everything else about it "heritage".)

and finally the fact that non-heritage tramways usingtrolleypoles rather than pantographs are a tiny minority if indeed anyexist at all.

Oh, don't get me wrong - I think it's a bonkers idea and I can't see why anyone would bother to install a new tramway that used trolley poles instead of pans. I'm more interested in the thought experiment of whether it not it's actually as "unpossible!" as might have been suggested.

The junction pointwork here is generally lightweight and simple, and even if it wasn't how much trouble would it be; an awful lot (crossovers etc.) can be done entirely passively, so given that a system like Croydon Tramlink would require all of about 3* sets of points how much overhead (no pun intended) do they really add? * Approximately, and I've not looked in detail, but pretty sure the central loop, and all the various sets of track points for the single line sections on the Wimbledon branch could be handled by passive trolley OHL with no points required - so the only places you need actual points in the OHL are Sandilands, Arena & Church Street. Even in the trailing direction, a frog casting in the OLE presents adisruption to smooth passage of the trolley head, and extra complication tothe layout of wiring and supporting wires, compared to having two plainwires which don’t even have to touch. Taking Croydon specifically, with a little imagination you could get awaywithout a facing frog in the OLE leaving any of the termini or the singleline sections, however you’d need them for entering the three double-tracktermini, at each end of the depot (and vastly increased complication withinthe depot), at Church Street, Sandilands, Arena and each end of EastCroydon. Plus, of course, you lose flexibility for any unusual working, wrong linemoves etc, without added operational complication.

How much of this is goldplating, though?

I mean, the depot, for example... Here, tram and trolleybus operations are simple because drivers are not too proud to routinely get out and use a point lever to change the points when necessary, or to manually move the trolley poles if needed. Does a depot really need fully automated switching, or could someone just buy the drivers some gloves?


--

On 09/02/2019 17:50, Anna Noyd-Dryver wrote:
wrote:
On Sat, 9 Feb 2019 18:57:48 +0200 (GMT+02:00)
Clank wrote:
Anna Noyd-Dryver Wrote in message:
Clank wrote: Anna Noyd-Dryver Anna@noyd-dryver=
..com Wrote in message: Clank wrote: On the =
other hand... What's wrong with trolley poles? They seem pretty reliab=
le even in inclement weather*. On a tram, where the poles wouldn't even=

Please introduce your news client to the concept of newlines.



Clank’s quoting of my recent posts has been rather odd. It it a problem
with my Usenet reader or his?


His I assume, I'm getting it too



--
Graeme Wall
This account not read.

Anna Noyd-Dryver wrote:
Marland wrote:
Anna Noyd-Dryver wrote:
Marland wrote:
Anna Noyd-Dryver wrote:
Marland wrote:
bob wrote:
Graeme Wall wrote:
On 08/02/2019 10:58, Bevan Price wrote:
On 08/02/19 4:14, Recliner wrote:
The DfT remains consistent in its dislike of OHLE

https://www.thetimes.co.uk/article/battery-powered-trams-to-beat-congestion-pzz3p9jk3?shareToken=d7efc8230f20d995b8ea4bff5daae 175





As usual, the incompetent DfT only thinks about short term costs of
initial construction, not the long term running / operating costs.

Batteries have a finite life. You can recharge them, but they eventually
deteriorate, hold less charge, and have to be replaced - and they are
not cheap to replace.

Moreover, you use additional energy to convey the weight of the
batteries on every journey, instead of getting energy from fixed
overhead wires to move a vehicle that is lighter due to the absence of
batteries.

And before anyone suggests fuel cells, they also have finite lives, and
to function, they often rely on the presence of rare, expensive,
precious metals (platinum, palladium, rhodium, etc.)


Though once you've done the difficult bit of the infrastructure,
actually getting the tracks in the road, adding OLE later is a much
simpler engineering task.

It is provided you’ve done the work to properly isolate the track return
current to prevent electrolytic corrosion problems. If not, it probably
means ripping the whole lot up again.


Or use twin conductors like a trolley bus.



That would necessitate use of trolley poles, where pantographs are the
current standard fitment for new tramways.

I suppose you could have twin pantographs as fitted for 3-phase on certain
mountain railways, though you might get polarity issues on single track
sections, plus I suspect the OLE then needs to be aligned more accurately,
thus making it more intrusive.


What polarity issues would that be? Trolley buses frequently moved poles
over to the opposite set to get around an obstruction or damaged section.
DC traction motors as used in trams ,trolleys and trains have the the field
windings made from coils and are not polarity sensitive, its only on small
DC motors with permanent magnets like on model trains etc that reversing
the polarity will make the motor rotate in a different direction.

Though in the unlikely event of such an installation happening would trams
still be using DC motors nowadays?
Or like most trains electronic gubbins that can be fed all sorts of things
then send it to a AC 3phase motors.


AIUI trolleybuses are designed with both the positive and negative traction
circuits fully isolated from the vehicle. Trams OTOH have the negative
side, ie rails, connected to to the vehicle underframe and body frame ie
everything is earthed. The two-wire tram would therefore need a
non-standard wiring loom etc.

AFAIK modern trams have separate traction wiring for both polarities though
as you say they will eventually arrive at the same earth point, but there
would not be much complication if the the cable to that was connected to a
second pole and wire, just not at the same time , any idea how London’s
conduit trams were wired? The conduit supply was not electrical different
from a two wire supply except the wires have become protected live rails,
the track was not used as the return . It must have taken some good

and wheel return would then be used. Did those trams have a switch that had
to be operated to go from plough return or track?

London conduit trams have a switch on the platform at one end to change
between pole and conduit (or between each pole and conduit if two separate
poles are fitted). I’ll have to enquire about how they’re wired and what
exactly is switched; however polarity shouldn’t be an issue as the London
conduit system didn’t have any single track AFAIK.

I think it was fairly rare as the conduit was in the busier inner area, in
a book I have somewhere there is a length single track under a bridge but
the two conduits are continued through the section.

GH

Anna Noyd-Dryver wrote:
Clank wrote:
Anna Noyd-Dryver Wrote in message:



With all due respect - and I use that in its extremely unusual totally
sincere sense - are all those true, or are they just "received wisdom"
used to back-justify the UK's resistance to trolleys (and indeed trams)?


My post was based on my knowledge and experience of UK heritage tramway
operations, my knowledge of UK heritage tramway maintenance, and of OLE
equipment fitted; and finally the fact that non-heritage tramways using
trolleypoles rather than pantographs are a tiny minority if indeed any
exist at all.

North America seems to be a bit of a hold out with Toronto ,Philadelphia
and Boston still using trolley poles
on normal services, New Orleans is arguable mainly a heritage operation
that locals happen to use because it is there. San Francisco definitely a
heritage operation.

Its worth noting that most of the last few UK systems that did do some
modernisation just before and after WW2 were no longer using poles with
Leeds ,Glasgow, Dundee,Aberdeen having switched to bow collectors and
Sunderland had used Pantographs for a while. Even Birmingham had converted
one route to bow before abandonment. The ones that closed late that
hadn’t were Liverpool ,Sheffield and Llandudno.
Even Blackpool changed most over eventually though to me the older ones
never looked quite right with a Pantograph.


GH

In article ,
Marland wrote:
North America seems to be a bit of a hold out with Toronto ,Philadelphia
and Boston still using trolley poles
on normal services, New Orleans is arguable mainly a heritage operation
that locals happen to use because it is there. San Francisco definitely a
heritage operation.

Toronto's newest cars have both pantographs and trolley poles, but
really need pantographs since the trolley poles can't provide full
power. They're in the process of updating the OHLE for pantographs,
supposed to be done next year.

https://en.wikipedia.org/wiki/Toront...ctrical_pickup

In Boston the main streetcar system, the green line, has used
pantographs since the Boeing LRVs in the 1970s. The Mattapan branch
of the red line, which is only 2.5 mi long, still uses ancient PCC
trolley cars, I gather because it would be very expensive to rebuild
the line to handle the green line cars. The community has rebuffed
suggestions to turn it into a busway. There are two trolleybus routes
from the Cambridge underground station out to the suburbs which
replaced streetcars a long time ago.

SEPTA in Philadelphia has a mix of equipment. The center city
subway-surface lines use Kawasaki cars with trolley poles, but the
suburban Media-Sharon Hill line uses the same cars with pantographs.
They also have one line operated by heritage PCCs, and three
trolleybus routes.

The F line in San Francisco uses an amazing mix of ancient heritage
cars. Despite the ancient equipment, it's a real line that goes
places other transit doesn't.

Haven't been to New Orleans lately.

--
Regards,
John Levine, , Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. https://jl.ly

On 09/02/2019 16:57, Clank wrote:

Anna Noyd-Dryver Wrote in message:

Clank wrote: Anna Noyd-Dryver Wrote in message: Clank wrote: On the other hand... What's wrong with trolley poles? They seem pretty reliable even in inclement weather*. On a tram, where the poles wouldn't even have to deal with the vehicle moving all over the road to overtake etc., I don't see any reason why they should be particularly problematic. More prone to dewirement, particularly as speed increases. Junction'pointwork' more complicated and prone to failure. More maintenancerequired too, I think. Need changing over at every terminus. Anna Noyd-Dryver With all due respect - and I use that in its extremely unusual totally sincere sense - are all those true, or are they just "received wisdom" used to back-justify the UK's resistance to trolleys (and indeed trams)? My post was based on my knowledge and experience of UK heritage tramwayoperations, my knowledge of UK heritage tramway maintenance, and of OLEequipment fitted;


Genuine question - do you think heritage operations are representative of modern equipment? Do you use modern OHLE in fact? (As I say, genuine question - not clear to me if a heritage tramway is all about the rolling stock or if you also try to keep everything else about it "heritage".)


and finally the fact that non-heritage tramways usingtrolleypoles rather than pantographs are a tiny minority if indeed anyexist at all.



I think that Riga still uses poles on their T3s, whilst there are a few
older PCCs running in San Francisco.

The Newark City Subway also used poles when they had PCCs.
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