Thanks to Ed Mello for this info: The "Fighting 71st" if from Arlington County Fire Station No. 1. I believe was made for the career personnel. Originally the fire companies were numbered 1 through 10. Then when mutual response began it was hard to distinguish between Arlington, Fairfax, and Alexandria companies so the equipment was renumbered. Each jurisdiction received a prefix...Arlington's was "7" so Company 1 became Company 71...thus the "71st." More recently there was another numbering change and the "7" was changed to "10." So now Company "1" or "71" is now Company "101."