So question: Why are those tunnels so large if only a bunch of cables need to run through them? I can understand if they made it so you can walk through it to inspect them, but this tunnel is much larger than a person.,(reply>), Lars Hoeksema It could be the smallest tunnel available boring equipment could create, or to leave room to add more cables as demand increases. Making a tunnel like this is really expensive to begin with, so you want to make sure you don't have to do it again.,(reply>), @seigeengine That would be correct, not sure why I added the inflection in this case.,(reply>), @Barney Laurance Thats also true. Whatever the reason i'm sure its a good one given how much it cost.,(reply>), +Lars Hoeksema Presumably they need space for more than just the bikes. If something needed replacing they would have to take a truck/cart to carry the new parts.,(reply>), +Nillie I know, but why not make it a smaller circle? I mean even if its like half the size it is now you can easily walk/cycle in there. And as long as someone can pass you relatively easily I still don't see the benefit of making it larger.