I can only guess, but there is a good chance that some track or other works are coming up where they want to disconnect just a shortish section of OH, and isolation from the Control Room would kill other lines as well. So they install this cheaper and simple insulator for local isolation later.

Nevertheless it is amazing how many insulators are placed in ‘nice and easy’ locations for the installers, making use of existing span poles, but being in totally hopeless places for tram drivers, like right at the departure from tram stops.

I occasionally got stuck on the one at the foot of Bourke St at Spencer St. Fortunately it is on the slightest of downgrades, enough for a B class to roll off when the brake release button was pressed - unless the tram’s 24v battery was flat when the charger went off!!

Richard

On 10 Jan 2019, at 4:19 pm, ma261065 mickalex@...> wrote:

Thanks Richard,

I wonder what the point of it is though, considering that it's bridged by the cable above it.

> On Thursday, January 10, 2019 at 4:06:58 PM UTC+11, Richard Youl wrote:

> I don’t recall seeing anybody reply to this.

>

> It looks to me like a basically standard break insulator, requiring the driver to cut power as the insulated material is almost certainly longer than the width of the pantograph.

>

> Usually bridging insulators have V shape wings to pick up the pantograph while it is still on the approach side section of overhead. These are quite common on the railways but there could be other designs more recently developed which I have not seen. I’ll have to keep an eye open in Melbourne next month.

>

> Regards,

>

> On 9 Jan 2019, at 9:01 pm, ma261065 mick...@...> wrote:

>

> Is this a breaking or no-break insulator (on Queen's Bridge)?