Cool video, thanks for sharing!!!!
More power will make track spin worse. Wider tracks or heavier equipment reduces track slipping.
They are using some heavy iron, probably the biggest they could get on site. The next bigger sizes, are more typical for quarry and mining.
Excavators
349E - very new design, 49ton machine, 13L, inline 6 engine, - very likely one of the new EPA Tier 4 Interim emissions engines
345C - 45-49ton machine, 13L, inline 6,
345D - 45-49ton machine, 13L, inline 6,
Track Type Tractors
D8T - ~43ton machine, 15L, inline 6,
D7E - ~29ton machine, 9.3L, inline 6 - This is one of Cat's revolutionary new designs, diesel over electric tractor.