The transport ministry wants to open a new tender for the Ruta del Sol 2 project.
Pampa acquired controlling stakes in each during 2016.
The US agency wishes to evaluate opportunities in aviation and rail infrastructure projects, as it has received funding requests from AA2000, Belgrano Cargas and air navigation agency EANA..
The operator will have to return control of the water supply network to Santa Marta city along with the information it has about users.
According to the state government, the recently approved reform to the local constitution regarding the provision of water services does not imply the participation of the private sector.
The divestment program's deadline is December 31.
The contracts for track repairs also include administration and maintenance of the lines.