He and his wife were watering the yard on Monday. When they came back outside to move the sprinkler, it was gone. A hole had formed in the middle of their lawn about three feet across and their sprinkler was at the bottom of a tunnel that had collapsed. They agree the structure was built after 1909 because railroad ties were used in the construction. That year is when the railroad first came to Lubbock from Plainview. Right now, the function of the structure is anyone's guess. "What it was used for, it would be nice to know, it really...