If you use the train, mark the weekend of 12–13 September: Transport for NSW has listed planned trackwork that takes the Southern Highlands Line out for the whole weekend.
The details, straight from the alerts. From 9.50pm Friday 11 September until 2am, buses replace trains between Moss Vale and Campbelltown. Then all day Saturday 12 and Sunday 13 September, buses replace trains between Goulburn, Moss Vale and East Hills. Replacement route 6SH stops at all stations between Moss Vale and Campbelltown — which includes Menangle Park.
Two things worth knowing about the buses: bikes aren't allowed on replacement services, and most (but not all) are Opal-enabled — so carry another way to pay just in case.
Connecting toward the city that weekend? The same alert flags that T8 Airport & South Line trains run a modified timetable between East Hills and the City, so allow extra time for the second leg too.
The weekend before (5–6 September) has a smaller change: two afternoon departures from Central leave earlier than timetabled — the 16:06 to Moss Vale departs at 16:03 (3 minutes early) and the 17:54 to Goulburn departs at 17:45 (9 minutes early). If you're cutting it fine at Central, that 9 minutes matters.
And for completeness: no trackwork is listed for this coming weekend (29–30 August) — we checked the official weekend trackwork map.
As always, alerts can change closer to the date — check the trip planner ↗ before you set out. More on trains and buses on our Getting around page.
More: Trackwork alert — Sat 12 & Sun 13 Sep ↗ · Trackwork alert — Fri 11 Sep evening ↗ · Timetable change — 5–6 Sep ↗