train tracks

Found this wheel at a railroad track about an inch or so under the ground. What is it? :icon_scratch:

Went to the train tracks today. Found a little grove of trees by an older house. Fist beep was super loud... up came this neat old wheel! Is it an old pram wheel? How old do ya think it is? There was tons of chunks of iron everywhere so I quit. But next year I'll go back with a good detector and...