The “Tracked” Steam Tank

Original post.

Author: P Radley

This large tank weighed 50 American tons (45 tonnes), had ½-inch thick (maximum) armour, a crew of 8, and had two 2-cylinder steam engines developing a total of 500hp, which moved it at 4mph (maximum). It was 34ft 9in (10.6m) long, 12ft 6in (3.8m) wide, and 10ft 4½in (3.2m) high. It was based on the British rhomboids, but had a distinctive shape all its own. Perhaps the most notable feature of it was the mud-clearing spikes on the front horns.

Its main armament was a new flame-thrower designed by Captain Henry Adams, an officer in the US Army Engineer Corps. A separate 35hp petrol engine provided 1,600lbs per sq in of pressure, to shoot the flame up to 90 feet (27m). As fitted, the flame projector was in the front plate, but it was proposed to later relocate this to a small turret above the front cab. However, there is no photographic evidence to show this actually happened. The tank also had a secondary armament of four 0.30-in machine guns in the sponsons.

Two 2-cylinder steam engines provided the motive power, and in the planning stage it was hoped they could also provide pressure for the flame projector, however, it was discovered that they did not provide sufficient pressure and a separate engine was installed for the flame thrower. The main engines, one per track, were activated by two kerosene burning boilers.

The Steam Tank was built in Boston and demonstrated in April 1918. It took part in some parades, but often broke down, as this passage from The Tech, volume 38, number 6, illustrates, “While on her way to the christening exercises, which were scheduled to take place at 5 o’clock Wednesday (17th April, 1918 -Ed) afternoon at Copley Square before a gathering of public officials and Army and Navy officers, the “America” stalled on the Cambridge bridge and it was some time before the mechanics could coax her to move again. This was due to some misadjustment of the mechanism and the huge caterpillar engine was removed to the garage for repairs, and the christening was postponed until Thursday.”

It seems the tank did get shipped to France (probably because the US Tank Commission was based in Paris and would not accept any tank for operational service with US forces until they had seen it and tested it) as there is this article, allegedly posted by a journalist in Paris, in The New York Herald of Saturday, June 22, 1918. “The first tank constructed in America will be ploughing its way across the battlefield in France to spread terror in Hun trenches. It has taken months to construct it, at a cost of $60,000. It is a giant in size, however, and is expected to overcome almost any obstacle that can be placed in its path by the enemy. The tank was constructed in a city near Boston. It crawled into Boston under its own power and was christened in historic Copley Square. Some idea of the tremendous size may be gained from the fact that a man may stand erect under the peak of its stern, which is but half the height of the land craft. It will be known as the America.”

The Tracked Steam Tank was not adopted by the US Army and did not enter service. Only the one example was built. Although little is known about the fate of the tank, it is believed she may have languished until perhaps the early 1930s before being broken up for scrap.


B.T. White. 1970. Tanks and and other Armored Fighting Vehicles 1900-1918. Blandford Press, London, England.
R.E. Jones, G.H. Rarey and R.J. Icks. 1930. The fighting tanks since 1916. The National Service Publishing Company, USA.
Vilkata. Landships Forum. August 7, 2005, and May 16, 2007.
Centurion. Landships Forum. July 1, 2006.
The Tech, Volume 38, Number 6. April 20, 1918.
The New York Herald. June 22, 1918, referenced in Mario Doherr, Landships Forum, August 9, 2005.