Manfred, I think Group f/64 should send you a letter. You're clearly working in aperture ranges none of my lenses have ever been set to.
Post 1, picture 3: Excellent sense of direction. Makes me want a pack and some good boots to head straight down the river.
Post 2, picture 2: The cris-crossing direction lines form the bridge and canal are interesting. Two leading lines creating a sort of virtual subject at their intersection. Clever.
Post 2, picture 5: Congrats for taking a non-cliche railroad shot! I would have framed it a little lower - I think there's a tad too much sky. But the detail's great, and the colors are uniformly dead-on in each of these shots.