Whenever I'm around Broadmeadows I often see one or two maintenance vehicles stabled in the siding there. They seem to come and go quite often. Does anyone know of their movements? Are they scheduled or as required? If you're after a number or type of vehicle I saw "Unimat 4S", I think. Anyway, it would be good to know when they move as it would be interesting seeing them in action going from one place to another. Thanks.
A 'Unimat 4S
' is a tamping machine
, specifically a switch tamper. They are often seen working in tandem with a smaller track machine known as a ballast regulator
Marcus Wong has a good selection of photos of track machines seen around the Melbourne network: https://railgallery.wongm.com/track-machines/
As for scheduling and movements: they're moved around the network as required. For a layperson the best chance of seeing rail maintenance machines in action is to check Metro's website for where and when planned maintenance works are occurring. Ballast tampers and ballast regulators are the easiest track machines to see in action as they take a while to do their work and are used quite frequently. They are always deployed after a ballast train has been run, but they are also run on an opportunistic basis by piggybacking on other line occupations for rail maintenance & construction works such as rail replacement, overhead renewals, station rebuilds and track occupations for level crossing removals and so on.