A "train yard" refers to a large area where trains are stored, repaired, and organized. It is like a parking lot for trains where they can be connected, disconnected, or fixed. Full definition
My daughter likes to visit the local train yard. (rookiemoms.com)
Pass the road test in the same training yard that you have trained on. (vikingdrivingschool.com)
Traveling widely from her home in Brooklyn, Halvorson's experiential process reaches outside the more common studio - based painting practices of New York City, taking her to train yards in Tennessee, a slaughterhouse in Iceland, and the English countryside. (art21.org)