In Helsinki they have human accessible tunnels because the whole city is on bedrock and there is not much soil above it. It's just way too hard to make tunnels to rock so small that people can't go there, so they're forced to be more accessible.
Tv, gas and power can be digged relatively shallow and I have not hear of maintenance tunnels for them when there is no solid rock to deal with.
With sewers they usually put vertical wells to it in every corner. That makes the whole system more accessible.
Often they put empty plastic tubes to new buildings just in case. It's not very hard to get something crawling there when new Internet comes to house.
Tv, gas and power can be digged relatively shallow and I have not hear of maintenance tunnels for them when there is no solid rock to deal with.
With sewers they usually put vertical wells to it in every corner. That makes the whole system more accessible.
Often they put empty plastic tubes to new buildings just in case. It's not very hard to get something crawling there when new Internet comes to house.