The Milwaukee Railroad may negotiate and enter into agreements to sell, to another rail carrier or any other person, all or any portion of its rail properties used in railroad operations as of October 15, 1979
. Such sale agreements may in no event become final and effective until the occurrence of an event described in section 920(b) of this title
, or April 1, 1980
, whichever first occurs. In taking action under this subsection, the Milwaukee Railroad may consult with the Secretary of Transportation.