There are some good suggestions here and I will also add to them in a minute but lets stop for a second and consider the situation. As far as the layout goes I am a one man band except for the electrical and the operation plan, everything else I do myself, everything, which includes locomotives and rolling stock and preparing the layout for running every week. So as much as I would like to add endless detail to the layout I can't, I just don't have the time, but your suggestions are always welcome don't be put off because of what I have said here because who knows I might just use some of them one day indeed I am thinking of cutting a piece of Black foam core and fitting it under the bridge to see what it looks like as Andre suggested.
While thinking about this bridge I thought of two other ways to go about this the first was to make up a much wider bridge which would almost be a tunnel and on top place a small shopping centre. You might remember a few years ago I did this to fill in a corner (See Photos). The second much easier was to make the bridge ONE lane wider and make the extra lane into a "Bus" lane for the commuters this was tempting as it would not interfere with the Backdrop as the lane would finish just before it reached the backdrop therefore the large factory would not be blocked off.
So what it comes down to I have decided due to lack of time to make just a simple two lane bridge with pavements on both sides and some plastic non working street lights and of course the usual motor vehicles and people. If later I decide I don't like that I will think of some alternatives then.
Don't forget I am getting closer to laying the four double slip switches soon that will be an interesting exercise in patience ! 
Thank you all. Roo.
