On May 19, 8:21*am, "Clive D. W. Feather" wrote:
In message , "

wrote:
I also notice that they have converted the signals in that area from
automatic to semi-automatic, or floodgate signals, as they are called
on the Northern Line. Why is that?
Not floodgate signals at all.
Just going on what they call them on the Northern Line,

Floodgate signals all have an F and an X in the number; e.g. FNX78 at
Leicester Square northbound.

The X indicates that they have to be treated as controlled and can't be
passed under the Rule. There are other X signals (e.g. CX81 at Leicester
Square southbound) that are so-numbered for train management or
signalling purposes even though they actually work automatically.

though yes, they are semi-automatic. The illuminated A under the signal
itself indicates that they are in automatic mode.

LU uses the term "semi-automatic" to mean what everyone else calls
"controlled", because they return to red behind a train even if the
controlling lever is reversed and because they'll clear again without
the lever being re-stroked. The ones with an illuminatible A are
"semi-automatic that can work automatically".

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I once read about a plan to turn Whitechapel into a Golders Green/
White City/Loughton/Arnos Grove type station with a central bi-
directional track. I guess that's ancient history?