Thank you Jake, I found the "Feature Vertices To Points" does not have the function to find the highest or lowest? (as below copied from this tool's online help)
ALL —A point will be created at each input feature vertex. This is the default.
MID —A point will be created at the midpoint, not necessarily a vertex, of each input line or polygon boundary.
START —A point will be created at the start point (first vertex) of each input feature.
END —A point will be created at the end point (last vertex) of each input feature.
BOTH_ENDS —Two points will be created, one at the start point and another at the endpoint of each input feature.
DANGLE —A dangle point will be created for any start or end point of an input line, if that point is not connected to another line at any location along that line. This option does not apply to polygon input.
Do I still have to export the attribute of the points and compare the Z values of each pipeline?
Cheers,