Hi Robin and welcome to the forum!
Not sure if you want response for the camera as a street photography tool or your black and white images. 
Certainly there are challenges in using B&W in low light... Personally I see the medium as allowing us to focus on texture, form and pattern when colour would otherwise be a distraction, but that generally requires a certain amount of light at the right angle to make the point. For people photography there needs to be something in their posture, expression, relative positions, grouping or action that draws us to the image and what is interesting must be able to be separated from the background, even if that is just an eye.. Taking B&W shots at night has its own challenges as you need enough dynamic range (i.e. tones) to allow the viewer to differentiate the subject from the background, something the 7D is not renowned for.
The first image has caught the different posture of people on the train - I am not sure about the blurring, but I like the character on the far right.
I particularly like your second shot, Light in the Dark: there is a hint of the buildings and I think it might be worthwhile to experiment with varying the dynamic range to see if bringing them out or totally suppressing them improves the result.
The Road Ahead is the classic texture and pattern shot, again worth experimenting with the contextual background.
City Lights is nicely done, perhaps increase the exposure and bring down the highlights slightly to avoid burning out the lit signs.
Capture Moods is more successful in gettig the character in the wash of light from the lamp and again brings out the texture of the road with a nice leading curve into the image top left. Maybe reduce highlights and bring up exposure slightly here too.
Tired of Rain for ME would work better if the figure was actually walking into the image, expecially since they are in front of the dark door.
Evening walk does not work for me. The figures are lost to the background - you might recoup something by the same method as suggested before.
I hope this helps...
