The Chinese rating agency best known for downgrading US sovereign debt last year has come under fire domestically for giving the country’s embattled railway ministry a higher rating than the government.

The controversy was sparked when Dagong Global Credit Rating reiterated its long-standing triple A rating on short-term financing paper issued by the railway ministry. The rating had garnered little attention previously. However, in the past six months the railway ministry’s reputation has been tarnished by a corruption scandal, soaring debt and a high-speed collision last month in which 40 people were killed.

The central government, which is ultimately responsible for railway debts, is rated one notch lower by Dagong at double A plus, an inconsistency Chinese media have pounced on.