The Secretary may extend the 3 - year period under subparagraph (A) up to a 30 - year period
for key stations in a rapid rail or light rail system which stations need extraordinarily expensive structural changes to, or replacement of, existing facilities; except that by the
last day of the 20th year following the date of the enactment of this Act at least 2/3 of such key stations must be
readily accessible to and usable by individuals with disabilities.