A
couchette (kuşet) is
a shelf-like bed in a European-style
six-person seating compartment.
The six seats can be quickly converted
to six couchettes complete with
pillow and blanket.
A
couchette is not as comfortable or
as private as asleeping-car berth:
the six passengers in the compartment
may be strangers to one another,
but must sleep in close proximity.
But
a couchette is more comfortable to
sleep in than a standard seat because
you can lie down and stretch out.
It's
also cheaper than a sleeping
car berth, though these days sleeping-car
berths on Turkish trains are quite
moderately-priced.