Guild Wars 2

How do you get these things repaired?
They are both normally broken, but occasionally are in working order.
Pretty useful in the Centaur event if they work.

have not actually done this event. was reading:
https://www.reddit.com/r/Guildwars2/comments/2g1p21/about_that_new_world_event_at_nebo_terrace/
though and it sounds like when the event starts they will be in full working order but if they get destroyed they are destroyed till the next time the event is up

Thanks for that info.
Tried again yesterday and one of the Trebuchets was working so used it until a centaur champ climbed the scaffold and killed me .
Event failed again.
If you really want a tuff challenge try this event.
Id say its now as hard as Teq .