Hello Twitter! I’m excited to start tunneling under downtown SF for @Central_Subway this year. Learn about me here: ow.ly/iwOnQ

— Mom Chung (@MomChungtheTBM) March 07, 2013

San Francisco is building a subway using two tunnel boring machines. The best part? They gave them each twitter accounts! You can follow them here:

• @BigAlmatheTBM
• @MomChungtheTBM