The steam from the cylinders passes directly into a condenser placed on the top of the carriage.  The condenser is made of corrigated copper sheets millimeter thick.  Two sheets, about 15 to 18 inches wide and 15 feet long, are laid together and firmly soldered, forming a chamber.  Twenty of these chambers are placed side by side on the top of the carriage, connected with a tube at each end, so as to allow the steam to pass freely through them.  The lower corrugations in the several chambers are connected together, and thence a pipe with a siphon to stop the steam is carried to a water tank under the carriage, which thus receives the condensed water.  This arrangement afforded a condensing surface of about 800 square feet.  It should be mentioned that with larger engines Mr. Rowan employs as much as 1,600 feet of condensing surface.  The nearness of the chambers to each other tends no doubt to diminish the power of condensing the steam, but this is somewhat compensated by the artificial circulation of air produced by the movement of the carriage.  But in any case, if there is surplus steam, the pipe from the condenser causes it to pass under the grate, whence it rises superheated and invisible through the fire and up the chimney.

Under the carriage attached to the framing are four reservoirs, holding about three and a half cubic feet of water, of which water space one-half acts as a reservoir for cold feed water, and half for the condensed water.  A tube from the small reservoir on the engine communicates through valves with the reservoirs of hot and cold water on the carriage.

The consumption of cold water measured during two days was 2.86 lb. per kilometer; assuming that the boiler evaporated 6.5 lb. of water per pound of coal, the cold water formed one-fifth of the total feed water required.

The carriage, i. e., the part occupied by passengers, is 21 ft. 8 in. in length.  It holds seats for forty-five passengers, besides those who would stand on the gangway and platform.  The seats are placed transversely on each side of a central corridor, each seat holding two people.  The platform of the carriage is about 2 ft. 6 in. above the rails.  Passengers have access to the interior from behind by means of the end platform, and in front near the engine from the two sides.  As already mentioned, the hind part of the carriage rests upon two wheels, the front part being, as already mentioned, supported on the engine bogie.  To effect this support, the hinder part of the framing of the engine is formed in a half circle, with a broad groove, in which the ends of two springs are arranged to slide.  The centers of the springs form the support of the framing of the carriage.

The framing of the engine bogie is attached to the hind bogie truck of the carriage by two diagonal drawbars.  The coupling is effected by bolts close to the engine, and the car is drawn entirely by means of the bogie pin of the hind bogie.  The trucks are 16.5 ft. apart.