(Adds detail on hurdles to complete Peru deals; adds details of talks to sell Supervia)
By Tatiana Bautzer and Carolina Mandl
SAO PAULO, May 10 (Reuters) - Brazilian creditors of conglomerate Odebrecht SA are leading the efforts to sell the group's commuter rail unit, Supervia Concessionaria de Transporte Ferroviario SA, as banks raise pressure on the corruption-ensnared group to accelerate asset sales, three people with knowledge of the matter said.
Odebrecht hired Banco BTG Pactual SA as an adviser months ago to sell Supervia, the sources added, asking for anonymity because talks are still private.
But failure to reach an agreement with potential acquirers following talks with investors caused creditors, led by Itau Unibanco Holding SA, to intervene, joining the efforts to sell the company through their investment banking units.
According to one of the sources with knowledge of the matter, Odebrecht did not agree on Supervia's valuation with the first group interested, United Arab Emirates' sovereign wealth fund Mubadala Development Co PJSC.
Last month, Odebrecht's construction unit failed to repay $144 million in bonds and said Odebrecht SA was still in negotiations with Banco Bradesco and Itaú to receive new loans to make the repayment within the 30-day grace period.
Talks for the loans are still ongoing, but other two people with knowledge of the matter said no agreement has been reached yet. Banks say Odebrecht's asset sales program is proceeding more slowly than expected. Supervia was seen by the banks as an example of the delayed assets sale.
Odebrecht has not received all the proceeds from the deals it announced, mostly due to legal hurdles to close deals in countries such as Peru.
For instance, Odebrecht sold its hydroelectric plant Chaglla in northern Peru last August to a consortium led by China Three Gorges Corp for $1.39 billion, but so far has not received the proceeds.
But creditors say in the case of Supervia, there is no pending legal issue preventing the sale.
Since Mubadala expressed interest in Supervia, two other groups, Starboard Restructuring Partners and RTM Brasil, showed interest and plan a joint bid, according to one of the sources.
BTG Pactual, Itaú, Mubadala and Starboard did not immediately comment on the matter. Odebrecht said in an emailed statement to Reuters that its transportation unit "is in talks with another investor to sell its stake in Supervia."
Odebrecht acquired 60 percent of Supervia in 2011. The company operates urban commuter trains in 12 cities in the state of Rio de Janeiro and transports around 750,000 people daily. (Additional reporting by Stanley Carvalho in Abu Dhabi; editing by Jeffrey Benkoe and Leslie Adler)