Complex sentence: Since 1991, the "Fondazzjoni Wirt Artna-Malta Heritage Trust" has been restoring the fort and has opened it to the public as a Museum, though the steam engine and hydraulic machinery have not yet been replaced.
Split into simpler sentences: Since 1991, the "Fondazzjoni Wirt Artna-Malta Heritage Trust" has been restoring the fort, which is now open to the public as a Museum. Unfortunately, the steam engine and hydraulic machinery have not yet been replaced.