Ключевые слова: background, building, city, concrete, construction, earth, engineering, equipment, ground, heavy, industrial, industry, iron, job, large, laying, light, line, machine, man, master, material, mechanical, metal, mound, new, operation, people, railroad, railway, reconstruction, repair, road, safety, sleepers, spark, stacking, steel, stone, technology, track, train, tram, transport, transportation, vehicle, welding, work, worker,