The first unofficial demonstration of the Christie M.1928, sanctioned by Charles P. Summerall (the Chief of Staff of the US Army from 1926 to 1930) occurred in October of 1928 in Fort Myer, Virginia. As a result, a decision was made to begin trials of the tank on Christie's dime. During a march from Fort Meade to Gettysburg and back, the tank achieved an average speed of 45 kph, while the maximum speed was 68 kph on tracks and 112 kph on wheels. After the first phase of trials, the tank returned to the US Wheel Track Layer Corporation factory in Rahway, New Jersey, where it underwent repairs. In June of 1929, army trials were completed, and the cavalry continued testing the tank.
The Christie tank ruined the Bureau of Ordnance's plans to replace over 200 M1917 tanks. Before the M.1928 appeared on the scene, the main contender for the main tank of American infantry was the Light Tank T1. In the summer and fall of 1928, the T1E1 tanks also marched between Fort Meade and Gettysburg. The average speed during the first run was 14.5 kph, the second was 16 kph. After such "impressive" results, the demonstration of the Christie tank was like a bomb falling on the military representatives.
Another two tanks were ordered in addition to the initial contract. There are varying opinions on what these tanks were. Peter Chamberlain writes that these tanks with six-speed gearboxes were tanks initially built for Poland. On the other hand, Polish sources say that only one tank was ordered. According to famous American tank historian Richard Hunnicut, only the seventh M.1931 had this gearbox, which only adds to the confusion. There is also no record of any such tank in the cavalry, and only one in the army (tank #7).
The first trial for the infantry's tanks was a march on June 17th, 1932, from Fort Benning to Fort McPherson, Georgia, and back. The tanks traveled 234 miles (377 km) on wheels. Tank #2 Tornado showed some issues with the oil system and tires. The other two tanks covered the distance without issues. The average speed of #6 Hurricane and #7 Cyclone was 21.6 and 24.18 mph (34.8 and 38.9 kph) respectively. The drivers did not feel fatigued after this prolonged march.
A report on the Convertible Medium Tank T3 dated January 17th, 1933, reads: "The infantry council is of the opinion that convertible drive tanks are the most appropriate for infantry and that Christie tanks surpass all other tanks built to this day."
The council recommended the standardization of the Christie Medium Tank T3 and supported the use of funds for modernization and purchase of new tanks of this type. By that time, F company's three tanks traveled a combined total of 1403 miles (2258 km). The tanks were worn out, especially in the suspension, but the results of the trials were positive. In addition to good mobility, the tank had powerful armament and was convenient to drive. The downside was the tank's think armour (up to 12.7 mm), but Christie's competitors were no better.