Snow Plough: MS of bulldozer backing up after clearing path through heavy snow. MLS of bulldozer ploughing through snow at foot of Rocky Mountain ridge. CS of snow being pushed ahead of plough of bulldozer. LS of snow blowing up high into canyon from snowblower as road is being opened at foot of Rocky Mountain ridge. TRAVELLING HASs of ploughed section of highway in canyon, of canyon and snow-covered hills beyond. LS across canyon of snow ploughed highway and railway tracks on mountainous ridge. LS and HAMLS of men and bulldozers clearing snow from railway track. LSs looking across stream of bulldozers and men clearing snow from railway track. LSs of men shoveling snow from snowed in passenger train in the Rockies, including TILT DOWN mountain to snowed-in train. MS and Cus of revolving wheel of snowblower. TRAVELLING SHOTs from machine moving along cleared road, of snow flying from snowblower into canyon below. CS of rotating wheel of snowblower disc.