It seems like the drivable car to the DMU on the other side of the train... Serie Ln 880 308/311, 4 units, built by Fiat Ferroviaria in 1976/77 (railfaneurope.net)
It is indeed the driving trailer, accompanied by an ALn 663 class diesel motor car. The Italian wiki on the FER mentions "diciassette Ln 880, costruite dalla Fiat Ferroviaria tra il 1971 e il 1983."