Final answer:
Without additional data on the usage rate of scouring powder, an exact figure for the annual usage in pounds cannot be determined. The question requires mathematical computation or estimation to be answered accurately.
Step-by-step explanation:
The question regarding the amount of scouring powder used at the average station in a year falls under the Mathematics category as it appears to involve mathematical computation or estimation. To provide an accurate answer, additional data such as the daily, weekly, or monthly usage rates would be required. Without this information, it is not possible to calculate or approximate the annual usage of scouring powder in pounds.