Alex,

I did see that the support arms may be hinged but I saw a likely weak point as the vertical support. Unless it is much stronger than it looks, it could give way during a misadventure.

I have no idea why the archives does not show the second photo but did see that Google had inserted their lines of text between the two photos for reasons unknown. I suppose this may have put the second photo in another category.

Richard

On 12 Feb 2019, at 10:52 am, 'Alex Cowie' via TramsDownUnder tramsdownunder@...> wrote:

Richard,
In the photo of the French design, the attachments of the crossarms to the vertical member look like hinged joints. The vertical member rigidly attached to the curved cantilever arm and the main mast effectively provide the same attachment points for the crossbars and their support stays as the centre poles in the Parkwood photo. Thus the French and Gold Coast installations provide similar independent support for the contact wires.

For some reason although the Parkwood photo is present when viewing in the Google Groups web interface and in the email version of your post, it has been replaced in your post in the TDU archive by a short Google Groups text file!

Alex C

> On Monday, February 11, 2019 at 8:24:17 PM UTC+10:30, Richard Youl wrote:

> All Of those look more attractive than the construction shown this morning. I have reproduced it below for anyone who may have forgotten.

>

> A closer look reveals that it is not a structure for catenary. The section of double wire on the right is only brief and probably is where a new wire comes in and the other ends. There is certainly no catenary on the closer track.

>

> For comparison I took a photograph at Parkwood East today, the second image below.

>

> I think this looks less intrusive than the French design which no doubt is intended to be stylish. The crossarms of the first mast include feeder wires coming from underground whereas the second mast is standard and is 40 m away, the standard mast spacing. Note the thinner pipe used in the top half.

>

> One feature of best design overhead is that the wires for the two tracks should be as independent as possible from each other so that if a pantograph or anything else snags the overhead, the wire for the second track is very much less damaged, or better still escapes damage.

>

> The Gold Coast support arms are attached by hinged pivots and a pantograph damaging one wire should have little affect on the other. It’s debatable whether this isolation is adequately designed into the ‘stylish’ French equipment.

>

> Richard