Then the vocal barlines are separate for each vocal part, but the piano barlines are connected. Organ A systemic barline connects all 3 staves. Then barlines connect all staves, except for the percussion part, which has a separate barline after the beginning systemic barline. A systemic barline connects all staves. Then connecting barlines are used on all staves.
Length is determind the same way as with single barlines.
Mark the end of a section of music, and usually precede a key or meter change. The 2 lines should be approx.