The Boring Company has posted on X:

Prufrock-4 has begun testing in Boring Factory in Bastrop, TX. Prufrock-4 is 308 feet long (~1 football field), weighs 797,000 pounds (~150 SUVs), and produces up to 4.7 million pounds of thrust (~90% of Falcon Heavy liftoff thrust).

https://twitter.com/boringcompany/status/1822814802819129673

Prufrock 4 is the latest iteration of TBC’s tunnel boring machine (TBM), meaning it should be closer to beating Gary the Snail. 

https://www.teslarati.com/the-boring-company-prufrock-4-tests/