When you go down to the jubilee line at southwark. Can't see any reason for any since it's an interchange?
Instead you have to go through two sets?
Suppose you are located between the Waterloo East NR barrier line and the LU Southwark barrier line, and the fire alarm goes off. Is the strategy to evacuate into the paid area of the unaffected station, or is there a direct fire escape from the intermediate unpaid area?
I think the question is, what fire alarm system activation will open the gates, that of Waterloo East, or Southwark, stations?
I would imagine that the Southwark and Waterloo East fire alarm systems are linked together, so one going off would trigger at least a warning on the other.
It is relatively simple to understand once you accept the Oyster PAYG ticketing logic that you must touch in and then out to make a journey. What you can't do is have an interchange gateline which could mean people touch in then out then out again.
At Southwark LU gated their station first. Waterloo East was ungated. The plan a long time ago was that there would be an exit to the street between where LU had a gateline and where Waterloo East's boundary was. It was never built meaning that you exited LU's paid area and were then immediately inside South Eastern's paid area. In the old days you could, in theory, wander through Waterloo East and then exit to the street without any intervention as the station was open. When South Eastern toddled along and gated Waterloo East they had no option but to put a gateline near the Southwark Gateline. This is so that people enter and exit each paid area in the proper sequence so the PAYG ticket logic can work correctly.
I'll stop you there because that's not quite right. The gateline for Waterloo East at the entrance to the overbridge from Waterloo proper is quite a recent installation, 2013 or 14.