Depends on what needs maintenance. Most of the common stuff can be done within the regiment or Cantonment itself by the EME regt responsible for maintenance, there is recently a somewhat increased focus on this.
At the EME college in Rawalpindi they have two separate Mechanical equipment training dept and electrical equipment training depts with one of each of the vehicles PA operates (or its corresponding electrical parts), they’re also used to train army techs that will form said mobile workshops.
If it’s a larger issue/repair they may be sent to the nearest major workshop like Gujranwala, Multan, Bahawalpur, Karachi etc. Plenty of artillery maintenance takes place at Gujranwala, Tanks at Bahawalpur. But for the newer equipment like SH-15 and VT-4 they might have to stick to 501/502/HIT until they can set up the necessary procedures to maintain these machines at other places (maybe they already have?). There’s currently a large amount of development and research work being done on the VT-4 of a certain nature, before we can entirely locally maintain it.
For further away regiments RWP is sort of a last resort and HIT is simply the army outsourcing it’s work for when it needs their advanced equipment, like gun barrel maintenance or electrical rebuilds/upgrades.
