Complex sentence: Once the manufacturing defects and corrosion damage were corrected, the R class proved to be a fine locomotive in its intended role of express passenger service, and individual R class locomotives were soon running upwards of each per week.
Split into simpler sentences: Once the manufacturing defects and corrosion damage were corrected, the R class proved to be a fine locomotive in its intended role of express passenger service. Individual R class locomotives were soon running upwards of each per week.