What's stopping big Bertha?

[Clodfobble]

But two weeks ago, a thousand feet into her near two-mile journey, Bertha came to a grinding halt.

Here's what I don't get. My kids watch this old show called "Popular Mechanics For Kids," which originally ran from 1997 to 2001. In one of the episodes, they do a segment on Big Bertha, including video footage of it up and running, so it's not like they were just profiling some future machine design that hadn't been built yet. At the latest, this episode was part of the final season in 2001, which would mean it's taken 12 years to dig 1,000 feet? What was the holdup?


Edit: nevermind, I'm dumb. I think the same machine gets moved from one construction site to another, and the video was from sometime earlier in its tunnel-digging career.