The main structure is 99% of a "Wills" kit and the adjoining retaining wall is made from the matching "Wills" embossed sheets (English bond to match that from the kit)
I then picked out individual bricks or groups of bricks with a lighter shade of Umbrol enamel (Light Blue)
Finally the whole job was given a couple of washes of watered down matt black emulsion to tone things down a bit,
The next job will be to glue the bridge and wall to the layout and add the road deck. The road deck will be made from thick card and painted an appropriate colour. But, I will have to ballast the section of track that passes under the bridge first as it will be awkward to do that once the bridge is fixed in place.
Another update soon!