\new Staff {
\once \set Staff.explicitKeySignatureVisibility = #end-of-line-invisible
% The next line is not needed in 2.11.x or later:
\once \override Staff.TimeSignature #'break-visibility = #end-of-line-invisible
\key f \major
\once \override Staff.TimeSignature #'stencil = ##f
\new Staff {
\once \set Staff.explicitKeySignatureVisibility = #end-of-line-invisible
% The next line is not needed in 2.11.x or later:
\once \override Staff.TimeSignature #'break-visibility = #end-of-line-invisible
\key f \major
\once \override Staff.TimeSignature #'stencil = ##f