Those who infiltrate often, do you stumble across service tunnels frequently (if at all)? Do you have any stories related to them?

Oh sure. They can be useful. Do be aware of what it feels like to be in bad air. Some service tunnels do not have ventilation. I prefer ones where I can feel wind.

In modern construction they're rarer, usually on campuses with underground steam tunnels (hospital, college). Pipes just don't need such frequent maintenance anymore. And since the entries are usually controlled, it's not so simple to get into places.

Once I nearly went into the VERY WRONG BUILDING through a tunnel, but I became aware of which basement I was about to enter. They hardly ever come out in bank basements anymore.

My favourite type of tunnel, but as I got older I stopped doing them due to the potential of getting caught, convicted & it affecting my job.

I find there is an adrenaline rush you don't get in many other tunnels.

Usually pretty fun to explore, but often have some kind of electronic security (though the extent can vary wildly) and are usually classified as critical infrastructure.

I find it really easy to find certain areas that seem like they would have said tunnels and just fuck around and find out. Sometimes you can get in through buildings, sometimes an exterior entrance like a manhole lid or hatch. But as stated previously in the thread beware of electronic security. I just like pokin' around with a butterknife and see where that takes me.

Posted by AnAppleSnail ...Some service tunnels do not have ventilation. I prefer ones where I can feel wind.... In modern construction they're rarer, usually on campuses with underground steam tunnels (hospital, college). Pipes just don't need such frequent maintenance anymore.

This should be obvious if you think about it, but rusting is oxidation and a confined space with a lot of rusting metal in it might have no oxygen. Apparently this kills a whole bunch of people in commercial maritime shipping every year, blew my mind to find out