1\version "2.19.36"
2
3\header {
4  texidoc = "The ledger-extra grob property increases
5the number of ledger lines drawn, but they are not
6drawn on top of staff lines."
7}
8
9notes = \relative {
10  \time 6/8
11  a4. b | c d | e f |
12  g4. a | b c | d e |
13  f4. g | a b |
14}
15
16\new Staff {
17  \notes
18}
19
20\new Staff {
21  \override Staff.StaffSymbol.ledger-extra = 1
22  \notes
23}
24
25\new Staff {
26  \override Staff.StaffSymbol.ledger-extra = 2
27  \notes
28}
29