Rail in
Definition 1 of 2
Pro Tip 1/3Physical Barriers
Refers to using actual barriers like fences or walls to contain something. 
The new playground was railed in for safety.
Pro Tip 2/3Property Lines
Used to demarcate the borders of personal property or areas. 
They railed in their yard to mark its limits.
Pro Tip 3/3Control Purpose
Implies the intent to control or restrict movement for protection or organization. 
The museum railed in the exhibits to direct visitor flow.