Complex sentence: The other Piraeus mainline station ("Peloponnese Station",) was used by metric line trains until 2005, when it was converted to standard gauge, reopening in 2007.
Split into simpler sentences: The other Piraeus mainline station ("Peloponnese Station",) was used by metric line trains until 2005. Afterward, it was closed and the metric track lifted and converted to standard gauge, reopening in 2007.