Yeah they are.. they have a few, their first was just off-the-shelf technology, the second is a hybrid, and their third one is apparently fully designed by Boring Co.:
I did more research and still came up blank - I saw a number of headlines talking about "boring company caves in" - but they use it as a metaphor for them abandoning plans to extend the tunnel significantly. Not an actual cave in.
If I am not mistaken the boring co test tunnels are actually slightly larger in diameter than the London tube tunnels (3.8m vs 3.6m), so you could actually run "standard" trains through those.
reply