Complex sentence: The open spaces of the Royal Carriage Works were similarly roofed over, and the area of its operations expanded; and a new Shot and Shell Foundry, completed in 1857, enabled manufacture of the latest types of ammunition.
Split into simpler sentences: The open spaces of the Royal Carriage Works were similarly roofed over, and the area of its operations expanded. A new Shot and Shell Foundry, completed in 1857, enabled manufacture of the latest types of ammunition.