Section IX-11: Acceptance of provisions of Constitution.

  No railroad, transportation, transmission, or other public
service corporation in existence at the time of the adoption of
this Constitution, shall have the benefit of any future
legislation, except on condition of complete acceptance of all
the provisions of this Constitution, applicable to railroads,
transportation companies, transmission companies, and other
public service corporations:  Provided, That nothing herein shall
be construed as validating any charter which may be invalid, or
waiving any of the conditions contained in any charter.