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the sills. The cast-iron columns of the inside front have cast-iron blocks at foot, 17^ in. X 17-2-in. X 9 in., resting upon cut-stone blocks, 2 ft. square by 1 ft. thick, with a stone foundation, 4 ft.square. The outer wall above the foundation is of brick, built in panels, with pilasters both insideand outside, and an ornamental outside cornice. The thickness of brick in panels is 13 in., and onpilasters 22 in. There are two windows in each panel on the outside of the house, excepting at theback of the house, where the house butts against the retaining-wall of 31st Street. A flush arch isbuilt in the wall on the inside over every pair of windows, to provide against any injury to thecornice and roof in the event of the wall below being damaged by locomotives running beyond theirstall. The window-openings are square, 5 ft. io£ in. X n ft., with cast-iron sills and lintels on theoutside. The windows have two sash, each 24 lights 10 in. X 15 in. The cast-iron inner front ofthe building is ^ in., and the columns are J in. thick. The doors are in pairs, circle-top, and 3 in.thick, panelled and glazed as shown, and leaving a clear opening in width of n ft. o£ in., and inheight of 18 ft. at the centre of the circle. Three of the 18 pairs of doors have small wicket-doors.Each door has three heavy wrought-iron strap-hinges hung on lugs cast to the columns. All thedoors open inward, and are provided with the proper fixtures for locking them, and also for holdingthem in place when swung open.
The engine-pits in the stalls are 42 ft. 6 in. long by 4 ft. wide in the clear, 2 ft. 9 in. deep at front,and 2 ft. 6 in. deep at back. The sidewalls are of stone, 2 ft. thick. The bottom is dished 2 in. inthe middle, and is paved with brick laid on edge and grouted with cement. Each pit drains at thelower end through a 10-in. bell-trap into a 12-in. circular brick sewer that runs under the ends of allthe pits and discharges into the main sewer leading from the house. The rails on the pits rest on6-in. X 12-in. white-oak stringers, anchored every 4 ft. with a i-in. anchor-bolt to the side-wallmasonry. The top of the rail is flush with the floor-level in the house. The inner end of the pitis located 10 ft. 5 in. from the inside face of the door, and the rear end is placed 10 ft. 5 in. from theinside face of the outside wall. The track in the house outside of the pits is laid on oak ties beddedin ballast. The floor is made of cement, laid level with the top of the rails on the pits and slightlydished to insure better drainage.
The roof-trusses are built on the triangular system, of iron and wood, the span being 65 ft. 4 in.from centre to centre of end-pins, with a rise of 16 ft. 3 in. The cast-iron end-plate on the innerfront is firmly, fixed to the top of the column, while at the outer front it rests on a 4-in. X 14-in.white-oak wall-plate. The principal rafters are white pine, 8 in. X xr in., and the struts are white pine,4 in. X 8 in. and 3 in. X 8 in. The heel-blocks, king-blocks, strut-caps, and strut-shoes are of cast-iron, f in. thick. The main tie-rods vary from 2 rods J in. in diameter to 2 rods 1^ in. in diameter.The counter-rods are in. in diameter. The purlins are of white pine, 4 in. X 8 in. on the inner circle,and 4 in. X xo in. on the outer circle. The purlins are cambered or cut convex on the outer circle,the rise at the centre of the purlin being 3I in. at the outer wall and 2-J in. near the ridge ; and theyare cut hollow or concave on the inner circle, the depression at the centre of the purlin being \ in. atthe inner wall and if in. near the ridge. The purlins are sheathed with ij-in. hemlock boards,covered with slate laid on two layers of roofing felt. Gutters of tin are provided on the outer andinner fronts, from which a 4-in. galvanized corrugated-iron pipe-conductor carries the water downthe outside wall on every alternate pilaster, discharging into an 8-in. clay-pipe drain that runsaround the outside of the building, while a 3-in. conductor carries the water down the inside front atevery alternate column, the pipe being located at the back of the column on the inside of the houseand discharging through a 4-in. clay-pipe drain into the 12-in. circular brick sewer running under theends of the engine-pits, as mentioned above.
Ventilation is secured by 6-ft. octagonal ornamental louvred ventilators placed in ridge of roofon every alternate stall. A sheet-iron'smoke-flue is placed over every stall, the centre of the flue being13 ft. from the inside face of the outer wall. The flue is 2 ft. in diameter, made of No. 14 gaugesheet-iron, and provided with a bell-shaped movable hood at the lower end, the bottom of the hoodwhen raised being 14 ft. 11 in. above the top of the rail, and 13 ft. 7 in. when lowered. Water-plugswith 3-in. standard fire-hose connection, protected by cast-iron boxes and covers level with top offloor, are provided at the centre of the house in alternate stalls, supplied by a 6-in. cast-iron water-pipe. There is an 8-in. X 8-in. white-oak bumping-log with iron plate at centre fastened on the floor