3-ton Special Tractor M1918.
This tank is armed with the Browning tank machine gun in the original ball mount. The driver was provided with a nonrotating vision cupola with vision slits. The axle for the idler wheels can be seen on the front bow plate, and the suspension springs were protected by plating. (Picture from Development of Armored Vehicles, volume 1: Tanks.)
This vehicle is armed with the Marlin machine gun in the redesigned ball mount. The gunner had a rearward-opening hatch on top of his position, but the only entry and exit was provided by the hatch in front of the driver. The leaf springs for the track return rollers can better be seen in this image. (Picture available from the National Archives.)
The tailpiece that assisted with trench crossing can be seen in this picture. An air intake louvre for the engine surmounts the rear hull, and an engine exhaust pipe exited on each side of the rear of the hull. Also note the arrangement of the sprocket teeth, with two teeth grouped together to grip the track links.
The hinges on the top of the crew access hatch can be better seen in the light in this image. The armament in this machine is a replica.
The attachment points for the tailpiece can be seen from the rear, and the engine exhausts at the top of the rear hull are now obvious. (Picture available from the National Archives.)
The driver was provided with no vision devices besides the slits in his cupola. (Picture available from the National Archives.)
The driver's door is open now, revealing the cramped position inside. Two 1 quart (1L) Pyrene fire extinguishers would be stowed inside as well.
The bottom of the front hull and inner side of the suspension bogies can be seen here.
The lower rear of the hull is detailed in this image.
Not much remains of the interior after over a century of existence, but the driver's steering levers and a pedal can be seen.
The twin engines and transmissions are seen here, with the driver's control levers to the front. The levers put the transmissions to which they were attached into low or high range by swinging them to the rear or front, respectively, with neutral in the center. A single 6-volt battery provided electrical storage. (Picture available from the National Archives.)
The rear of this tank was redesigned to improve cooling, and the engine exhaust pipes were rerouted to exit the tank behind the drive sprockets. (Picture from Development of Armored Vehicles, volume 1: Tanks.)
The very small size of the vehicles is apparent when their test crews are seen standing beside them. (Picture available from the National Archives.)
