SDO is normally used to allow one set of doors to be off the
platform, not an entire coach at each end.

The Southern 377s have the capability not to enable the doors on one or
maybe more coaches, and they make helpful automated (though not always
correct) announcements like 'Customers for XYZ should travel in the front 7
coaches; this is coach 4 of 8'.

Peter

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|| Peter CS ~ Epsom ~ UK | pjcs02 [at] gmail.com |