This was an item on a particularly set of bad temporary timetables that underestimated travel demand over the summer of 2013-14. They were still in effect in late January by which time many people had already returned to work. They had some big gaps between trips and offered insufficient capacity.
This was the last (or one of the last) occurrences of reduced service summer timetables. In later years the regular timetables ran right through summer (except for public holidays). Although there are often construction works scheduled so trains on some lines may be replaced by buses.
https://web.archive.org/web/20131228034729/http://www.metrotrains.com.au/travelling-with-metro-over-summer
Note: Item added retrospectively for posterity.
