Ключевые слова: arrow, attention, black, blue, caution, danger, direction, gravel, green, industry, information, iron, journey, line, metal, nature, old, perspective, rail, railroad, rails, railway, red, road, road sign, roadsign, safety, sign, signpost, sky, speed, station, steel, stone, street, symbol, track, tracks, traffic, traffic sign, train, transit, transport, transportation, travel, triangle, warning, way, yellow,