Minneapolis' $2 billion Southwest light-rail construction work uses Japanese equipment pressing (as opposed to pounding or vibrating) vertical steel sheet piles into the ground to create an interlocking wall that will serve as the framework for the concrete tunnel. They are doing it so to minimie the noise and other disruption as the constructions has to be done in a densely populated neighbourhood.

http://www.startribune.com/construction-begins-on-southwest-light-rail-tunnel/566978052/