Praefectus castrorum

The praefectus castrorum ("camp prefect") was, in the Roman army of the early Empire, the third most senior commander of the Roman legion after the legate (legatus) and the senior military tribune (tribunus laticlavius). His responsibility was looking after equipment and building works but he could command the legion when his seniors were absent. The post was usually held by men coming from the ranks of the centurionate, having already served as chief centurions (primus pilus) of a legion, and was therefore open to ordinary citizens. A camp prefect's job was to maintain and update the equipment, organize the legion, and make sure that the soldiers were properly trained. Prefects of this rank, including Sextus Vibius Gallus, were awarded prizes (dona) to mark their achievements.

...
Wikipedia