Bar line problem

[Palmer, Ralph]

Greetings -

I'm a novice at LilyPond. I'm running LilyPond 2.8.4.1 on Windows XP
Professional, V. 2002, SP2.

I cannot figure out how to set a particular pair of bar lines. In the
following file, the default line breaks occur where I would like them -
after each 4 measures. At the end of Part B (which coincides with a
default line break), I would like to show a section break ( || ). I'd
also like to have an open repeat ( |: ) at the start of Part C (= the
start of the next line). I got the "||" to work properly, but there was
no "|:" to open the repeat section. When I forced the "|:" ( \bar "|:"
), the section break disappeared and became a regular bar line. I tried
forcing the line break after the section break at the end of Part B, but
that didn't work.

Does anyone have any suggestions?

Thank you for your time and attention,

Ralph
+++++++++++++++++++++++++
Ralph Palmer
Energy/Administrative Coordinator
Keene State College
Keene, NH 03435-2502
Phone: 603-358-2230
Cell: 603-209-2903
Fax: 603-358-2456
address@hidden


%%%%%%%%%%%%%%%%%%%%%%

%Gravel Walk
\version "2.8.4.1"
\header {
        title = "Gravel Walk"
        composer = "Traditional (Nova Scotia)"
}

melody = \relative c' {
        \clef treble
        \key a \dorian
        \time 2/2
        
        %Part A
        \repeat volta 2 {
                a'4 e'8[ a,] \times 2/3 {c[( b a])} e'[ a,]
                \times 2/3 {c[( b a])} e'[ a,] b a g b
                a4 e'8 a, \times 2/3 {b[( c d])} e fis
                g e d c b a g b
        }
        
        %Part B
        a16[ a a8] a' a, g' a, fis' a,
        a16[ a a8] e' a, b a g b 
        a16[ a a8] a' a, g' a, fis' a,
        g' e d c b a g b 
        a16[ a a8] a' a, g' a, fis' a,
        a16[ a a8] e' a, b a g b 
        a b c d e fis g a 
        g e d c b a g b 
        \bar "||"
        
        %Part C
        \repeat volta 2 {
                \bar "|:"
                \times 2/3 {c[( b a])} b g a4. b8
                c a a d b g b d 
                \times 2/3 {c[( b a)]} b g a b c d 
                e fis g e d b g b
        }
        
        %Part D
}

\score {
        { \melody }
}