Ted, the northern is pretty much completely rebuilt to add a fan driven smoke unit. Ed Goldin developed the conversion design and selected the specific parts. He has a video on his website of one of the engines operating. He now offers this as one of his standard modifications.
Mark is is sunlight and it was completely serendipitous. I went to the layout to take some quick pictures between conference calls I had scheduled. I noticed the sunlight and shadows when I posted the pictures. If I had more time I would have turned on all the building lights and moved a train onto the green bridge.
