The major railroad in town was the Frisco, now BNSF. I spent an afternoon watching trains at Sapulpa, but traffic is not as heavy as the transcon, so it's a spin of the wheel of fortune. Santa Fe pulled out years ago, and the Midland Valley was truncated on both sides of town. However, there are two switching outfits that are kind of interesting.
There's the Sand Springs Railway which used to keep its little EMD's so clean you could eat off of the floor.
Another is the Tulsa Sapulpa Union Railway which also runs small EMD's.