On May 24, 2012, the contract with TBA to operate the Mitre and Sarmiento lines was revoked by the Government of Argentina after the Once station rail disaster. As a result, UGOMS took over the Mitre Line until it was granted in concession. The San Martín Line was granted to UGOFE, a consortium formed by railway companies Ferrovías, Metrovías and TBA, although TBA would be excluded from it a few days later.