A mobility concept tested in several forms
The Christie M1928 and M1931 development line explored a tank that could travel on tracks across country and on large rubber-tired road wheels when its tracks were removed. Published accounts describe the M1928 demonstrator, improved M1931, Infantry T3, and Cavalry T1 as connected but distinct stages. Their common emphasis was speed and suspension travel, not a single unchanging fighting configuration. Sources
The repeated names are easy to misread. “Model 1940” was a forward-looking designation attached to the earlier demonstrator, not evidence of a 1940 construction date. The Christie Combat Car T1 was also not the Cunningham/Ordnance Light Tank T1 covered in account 052. Sources
The demonstrator and the Army’s interest
The interwar Army was attempting to improve mobility while working with a small budget and much older equipment. The account frames Christie's vehicle against that situation and against differing Infantry, Cavalry, and Ordnance priorities. Branch terminology shaped the names used for experimental vehicles; calling a machine a combat car does not by itself explain its mechanical configuration. Sources
The 1928 demonstrator contrasted dramatically with slow First World War tanks. It combined a powerful Liberty aircraft engine with large road wheels and considerable suspension movement. The source account explicitly says it lacked a normal completed turret-and-armament system. Demonstration speeds commonly quoted around 45 mph on tracks and 70 mph on wheels therefore belong to that particular experimental vehicle and source context, not to every later Army T3 or T1. Sources
The demonstrations attracted attention, but a fast chassis still needed weapons, a workable crew arrangement, protection, maintenance, and an acceptable procurement relationship. The available evidence describes the tension between Christie's inventive strengths and Army requirements without equating publicity success with standardization. Sources
M1931 procurement and the seven-vehicle allocation
The M1931 was the improved military form. Published accounts give conflicting contract chronologies: one account emphasizes a June 1931 order for seven vehicles, while others describe an earlier pilot contract and an intermediate order that was later expanded or consolidated. These may describe different procurement events, but the available material does not justify silently treating that explanation as proved. Sources
The more consistent service allocation is three vehicles for Infantry as T3s and four for Cavalry as T1s. The published account’s broader nine-vehicle figure is retained as an accounting question rather than added to the seven. Prototypes, contracts, exports, and Army deliveries may fall within different counting boundaries. Until a hull ledger is established, the family overview cannot claim an exact worldwide production total assembled by summing incompatible source numbers. Sources
Hull, turret, and the two-man crew
The military vehicle had a pointed front, a forward driver, a small turret, and a rear powerpack. Its large wheels and suspension housings shaped both its appearance and its usable internal space. With only two crew members, the second man had to combine command and weapon duties. that compressed arrangement is described as a limitation alongside the mobility advantages. Sources
The Army historical account cited by the available evidence says the Army had to provide the turrets because Christie's work did not supply a complete ordnance system. This separates the mobility chassis from its fighting equipment and helps explain why a turretless export or demonstration photograph cannot establish an American service armament fit. Sources
Armor was light, with reported figures around half an inch to five-eighths of an inch for the T3. Those are not a complete plate map. Exact ammunition stowage and sight nomenclature are not established in the cited sources. An apparently simple gun arrangement cannot invite guessed ammunition capacities or a sight model borrowed from another tank. Sources
Armament is not settled by a branch label
The Infantry T3 is consistently associated with a turreted 37 mm gun, usually identified as the M1916, and a coaxial.30-caliber machine gun. Cavalry T1 descriptions are less consistent. Some summaries make a.50-caliber weapon the general distinction, while another source argues that several Cavalry vehicles retained the gun arrangement and that a particular under-armed vehicle distorted later accounts. Sources
Published accounts describe those competing descriptions. It does not use one photograph to assign identical armament to all four Cavalry vehicles, nor does it automatically caption every T1 as a machine-gun-only tank. The Fort Knox photograph is specifically described as retaining the 37 mm mounting. Its dated configuration is evidence to connect to a vehicle record, not a substitute for examining the entire allocation and subsequent modifications. Sources
Power, suspension, and convertible running
The Liberty engine rating is another source-dependent figure. The Army history used in Published accounts describe 338 hp for the demonstrator and service vehicles; other summaries quote approximately 449 hp. The available evidence proposes possible rating differences but does not establish their cause. Published accounts describe the conflict instead of declaring gross-versus-net output to be the solution. Sources
Large road wheels with long suspension travel allowed movement on wheels after removal of the tracks. Track carriage and the conversion procedure were part of the system's practical burden. Demonstration mobility is separate from the lower tracked and wheeled figures reported for service-trial vehicles, and from claims about track life or sustained cross-country reliability. Sources
The layout promised operational flexibility but did not remove the need for durable tracks, accessible machinery, usable crew space, and appropriate fighting equipment. Radio installations and later mechanical alterations also varied. The account does not confirm a single model of radio or identical final equipment across the whole family. Sources
Trials, modifications, and related development
The Army used the T3s and T1s for experimental mechanization, marches, and demonstrations, including work associated with Fort Benning and Fort Knox. The account does not assign them a U.S. combat history. Names such as Tornado, Hurricane, and Cyclone refer to individual vehicles or records, not automatically to new variants. Sources
Individual vehicle histories remain incomplete. Sources
Foreign interest is also distinct from U.S. Army use. Soviet purchases and the subsequent BT path, British connections, and the uncertain Polish procurement story are separate questions. The available evidence supports a discussion of influence and transfer, but not a claim that every later fast tank was merely another M1931 configuration or that one invention alone produced later wartime success. Sources
The surviving image record
The pictures show a Rahway demonstration vehicle, an American Cavalry test configuration, and a composite of two Soviet trial photographs. The composite is one stored image file containing two views; it is not evidence of two additional American production vehicles. Its turretless state also makes it unsuitable as an unqualified illustration of the armed Infantry T3. Sources
The original provenance references remain attached, including Hunnicutt book citations and the source assertions about government or public-domain status. Those references do not mean every underlying book or archive has already been examined. Sources
Photograph and image credit
Background reading and references. Each photograph has its own source and credit.
Sources and further reading
Background reading and references. Each photograph has its own source and credit.
- U.S. Army Ordnance Corps Hall of Fame, "Mr. J Walter Christie" — Accessed May 31, 2026
- Konrad F. Schreier Jr., "U.S. Army Tank Development 1925-1940," ARMOR / U.S. Army eARMOR — Accessed May 31, 2026
- Michael Green, American Tanks & AFVs of World War II, preview text — Accessed May 31, 2026
- George F. Hofmann, "The American Roots of Blitzkrieg," ARMOR, November-December 2001 — Accessed May 31, 2026
- John Rickard, "Christie M1931/ Medium Tank T3/ Combat Car T1," HistoryOfWar.org, 20 April 2016 — Accessed May 31, 2026
- Armor Archives, "Christie M1931," 18 November 2016 — Accessed May 31, 2026
- U.S. Army Center of Military History, "U.S. Army Armor & Cavalry Training Support Facility" — Accessed May 31, 2026
- Wikimedia Commons, File:Christie M.1931 Rahway.jpg — Accessed May 31, 2026
- Wikimedia Commons, File:Convertible Combat Car T1.png — Accessed May 31, 2026
- Wikimedia Commons, File:Tank M.1940.jpg — Accessed May 31, 2026
