Smoking jackets were all the rage in the upper crust during the middle of the last century. Usually associated with fine cigars and brandy after dinner. Like a robe but shorter like a blazer..
..Oh, you mean "Smoke Jacks!" Enginehouse/roundhouse ventilators! Of course. Yes they were rectangular or square or round if made of ventilator pipes. It all depends on the railroad and how they chose to build them. Normally they are capped to keep the weather out but open enough to let the heat and smoke leave the building. The rectanglular ones usually had vertical slats on the sides and a peaked or flat roof on the top. These would create a draft as the wind blew across them. Round ones were like large stovepipes with usually a cone shaped cover.