On Thu, 07 Aug 2014 15:43:27 +0100, Paul Corfield wrote:

On Thu, 7 Aug 2014 09:29:56 +0100, Roland Perry
wrote:

That's been done 600 times already, so we have to assume the mechanical
aspects are well understood.

And of course every installation works perfectly, there are no site or
system or comms issues etc etc. You know as well as I do that all sorts
of issues can arise in the real world.

I doubt that after 600 installations over the Greater London area there's
any real potential for a new "not already been solved somewhere once"
issue to arise. The worst cases might involve running new copper or fibre
for a comms line, or needing to increase the capacity of the electricity
feed to the station, but these are everyday occurrences in the
telecommunications and electricity supply world. The requirements from
the physical and connectivity side are fairly straight forwards:

- A suitable point between the ticket office and the platform for
barriers (or possibly just a touch in / out pillar?)
- Sufficient electrical and comms links
- Space for any supporting equipment in a suitable equipment room

Perhaps a "2 platforms with bus shelters and a footbridge halt" might
need a new lineside cabinet style "equipment room" installed, but that's
probably about the limit of exceptional circumstances in such
installations.

--
Denis McMahon,