[farothel]

So standard manhole, no, but other (larger-sized) underground access, yes.  If they can get a backhoe down there ...

I think it was a flooding system (so not sewage, but only water), but the guys in Top Gear once drove a car through one (can't recall the episode though).  if they can fit a car, you can fit a troll.

[Raven2049]

that was germany Belfast i believe, but cant remember, and yes it was supposedly a sewer drain, but i dont believe that for a second. it was more than likely a stormwater run off. and besides that, it was the main (or close to the main) trunk of the line, the secondary lines are much smaller, and have much smaller access holes.   



EDIT. found the video: https://www.youtube.com/watch?v=-TbpgZ2Dt0A

[farothel]

That was the one.  And as I said before: In the big mains, you can fit a troll, in the smaller ones they will have difficulties.

But I think they will go in there with drones as then 1 person can watch a whole group of them and they only send teams down there if there's a problem the drones can't handle.

[Senko]

Mmmm Roto-rooter taking your jobs since 2057. I admit there's a lot of dangerous confined spaces where having automated drones do the basic maintenance would make sense. Even some industrial equipment it could be nice so you don't risk loosing a hand knocking an obstruction loose because some idiot ignore's the isolation tags.