MARTA has gone to court to defend its right to outsource its bus service for the disabled and elderly to a private company.

In February an arbitration board overturned MARTA's 2015 decision to outsource its paratransit service to MV Transportation. MARTA says it made the move to save money, increase efficiency and improve on-time performance rates. But the Amalgamated Transit Union said the decision violated the terms of its MARTA labor contract, and the arbitration board agreed.

On Tuesday MARTA appealed that decision to Fulton County Superior Court. In a lawsuit filed against the union, it says the arbitration board overstepped its legal authority and asked the court to overturn the decision.