In article , Stephen Furley
writes

Gap fillers, like those at South Ferry on the New York subway? For those
that haven't seem them, these consist of an area of platform comprised of
many parallel steel bars, running back from the edge of the platform edge
for a metre or so, and wide enough to cover the width of the open doors when
the train stops. The bars are in two sets, alternate ones being fixed and
movable, when the train arrives the movable set moves forward to fill the
gap between the train and the platform edge. There are chains at the sides
of them at various hights, to prevent passengers falling off the side.
Probably be banned of safety grounds here. The bars might need to be at a
closer pitch than those in New York, to prevent a wheel from falling down
the gap between them when extended. The New York ones are about the size of
the cleats on the steps on the old 'wooden' escalators.

I've used the NYC subway and the 'gap fillers' aren't wheelchair
compatible.

They simply stop someone falling into a void - they do not provide a
smooth, slat bridge between the platform adn the carriage.
--
Andrew
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