Shots of men at work in tunnel at night, hosing down concrete floor, walls with steam hose, carrying out various jobs, much steam in the air. HAS of pouring of cement, of engineers discussing job. HAS of tractor-mounted tool being driven ahead. HAS of men at work, much steam. Shots of welder at work, bulldozers dozing. TILT DOWN, TILT UP to men operating jackhammers. PAN from men holding high pressure hose to water jetting out of nozzle as men hose down rocks. MLSs of bulldozers at work, men standing by, engineers with transit, bulldozers in background, man with jackhammer.