"We need to extend our investigation to be able to make a final decision," a spokesman for the cartel office said. The watchdog can examine the plans for an additional three months.

The deal, first announced in August, foresees Vossloh selling the unit to CRRC Zhuzhou Locomotive for a low single-digit million euro sum.

An industry source told Reuters earlier this month that Germany's Economy Ministry was mulling a veto against the deal, which would expand CRRC's foothold in Europe.

(Reporting by Matthias Inverardi; Writing by Christph Steitz; Editing by Tassilo Hummel)