São Paulo state could enjoy cost reductions due to resulting competition.
Launched by prosecutors and federal police on Tuesday, the investigation is focused on potential wrongdoings involving public transportation contracts in Rio de Janeiro state.
The government is ramping up infrastructure investment as the country benefits from higher commodities export revenue.
The two consortiums have until July 2018 to deliver the structured projects.
Concessionaire Terminal Puerto Coquimbo (TPC) submitted an environmental impact study for the project.
The chosen advisor will help define the scope of the contract for the national backbone network and promote the project in order to define financing schemes.
The Transnordestina railway initiative is a major project that has been halted by the country's court of accounts.