Hi Petra,
Thank you for posting more coolness :8
The colour version looks better now, but I definitely like the B&W cone better. To really get rid of the double colour cast in the colour version you'd need to brush in even more e.g. White Balance corrections, you'll have to do this split; one end needs more green tint, the other more magenta. Not easy to do perfect… But as I think the B&W version already is so very nice I wouldn't bother with this (even if you do it perfectly, you probably will like the B&W much more anyway).
Some feedback on the new images (as always, this is my personal opinion so feel encouraged to disagree

:
Walkway: Nice, very nice, really like the dark mood. I'd basically only correct the tilt/perspective of the of the image to get it perfectly straight.
Light: Interesting! Here, I'd add a bit more colour and enhance the “structure” (a lot) to make it even more interesting.
Valve: Like it! But see previous comment (though this one would work very well in B&W too).
Open space: Hmm, this one doesn't seem to work for me. Too many (distracting) things going on without a real subject (for me at least). Perhaps if you straightened it, it would bring back some “balance”.
The first three are definite keepers though

Thanks for sharing,
Hayo