Portugal 2-10-0T tank engine with a mixed passenger/freight train, 1968

It was a highly distinctive, articulated Mallet compound tank locomotive class. Built initially in 1910 and again in 1923 by Henschel & Son for the Portuguese railways, these uncommon mixed-traffic engines featured two separate sets of driving wheels (a 2-4-6-0 wheel arrangement) built on a single rigid frame. 

One of the surviving engines from this series (Class E, specifically No. E 38) has been set aside for preservation and static display on the tracks just north of the Pocinho Station in northern Portugal. It is located near the terraced vineyards of the Douro Valley (the pic likely shows the Duoro River), close to the Pocinho railway museum stop.