Original configuration of structure east of W 8th st?

[Passenger]

That is two level station near the NY Aquarium.

What is there now and has been since the 1960s when I first saw it -- The tracks from the Brighton line to the east for to the upper level, and the Culver line from the north go underneath.

However the structure from the east has two outer structures that would support tracks but don't have any. These branch off from the Brighton line tracks and merge with the structures that go underneath.

What were these used for when there were tracks? And when? Non-revenue moves?

Here's a picture for reference:
http://nycsubway.org/perl/show?109709

Thanks.

[Kamen Rider]

When the line was opened in 1920, Culver service was an afterthough south of Kings Highway. Most service on non peak times (such as high beach traffic days) were El shuttle trains. West 8th lower was feed from the Brighton Local tracks, allowing four track brigton service the whole way to Coney Island. The concetion was finnaly pulled in 1954, after the Culver ramp was routed through and the D train made full length, full time culver service a nessisty.

[Passenger]

Thanks.