diff --git a/src/calibre/ebooks/txt/processor.py b/src/calibre/ebooks/txt/processor.py
index 55213381c9..7e161f63bd 100644
--- a/src/calibre/ebooks/txt/processor.py
+++ b/src/calibre/ebooks/txt/processor.py
@@ -126,7 +126,7 @@ def separate_hard_scene_breaks(txt):
             return '\n%s\n' % line
         else:
             return line
-    txt = re.sub(u'(?miu)^[ \t-=~\/]+$', lambda mo: sep_break(mo.group()), txt)
+    txt = re.sub(u'(?miu)^[ \t-=~\/_]+$', lambda mo: sep_break(mo.group()), txt)
     return txt
 
 def block_to_single_line(txt):