If it's a large yard, you could opt for a tall obervation yard tower like the one in Bailey Yard in North Platte. Obviously no one is going to model a yard that big but you could build a tower like that.
bailey-yard.jpg (1400×522) (onlyinyourstate.com)
I think the higher you build the tower, the less obvious it will be that there is a post sticking out above it.
Make the bottom a small two-story yard office either by putting styrene walls with doors and windows around it or print something off the computer and wrap it around the post. Above that paint the rest blue sky and clouds, you'll never see it. If you extend the building out on one side it will make it seem like it is even less part of the post.
Put mirrors around it and you will just see railcars and track in the post.
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
7" square?
You can either wrap it with something that makes it look like something tall that is 50' square (haven't a clue what would qualify),
or,
you can wrap it with something much bigger. But is also pretty tall. A grain elevator comes to mind. Just look around for tall industrial buildings near railroad tracks. With the grain elevator, you can make rail deliveries, too!
Whatever you decide to build around it, there will come a point where it just can't be THAT tall, and your creation stops. And the column continues. So you paint it. My choice would be flat black, but there's also a neutral grey, or "sky" blue.
Ed
The way my room is laid out, I am going to have a post, about 7x7" that is going to be IN my layout. Its in a yard type area. Any creative ideas how I can hide or integrate it somehow? Ive tried redesigning things over and over but really can get "around" it.