As new Montreal skyscrapers rise one after the other to vie for a place in the sun, a matching feat of engineering is taking place in the solid bedrock upon which they stand. Montreal's underground railway, now with half its tunnelling completed, is scheduled for preliminary operation in 1966 and completion in Canada's centennial year of '67. Outstanding feature of the Montreal Metro, which will be the most modern subway system in the world, will be the huge pneumatic-tired wheels of the subway cars, providing passengers with a quieter ride, smooth, rapid starts-and-stops and the ability to take steeper grades than conventional grinding metal wheels. For now, the work of hard-rock tunnelling, concreting, and station building proceeds apace as Canada's largest city digs deep to finish the world's first complete system of underground travel using the quiet luxury of rubber-wheeled trains.