Complex sentence: A Fire Engine was located within the hosiptal grounds in the event of a fire, (another still exists at Rhodes), although these motors were also in case of a fire/explosion at the then operating nearby Mortlake Gas Works.
Split into simpler sentences: A Fire Engine was located within the hospital grounds for use in the event of a fire; another was placed at Rhodes. These motors were also intended for use in case of a fire/explosion at the then nearby Mortlake Gas Works.