The Sumida type 91 So-Mo model is here
Kindly corrected by mr Akira Takizawa
In 1930 was produced the Sumida model P armored car by Ishikawajima. This vehicle was only used by the landing forces of the Imperial Japanese Navy (SNLF: Special Naval Landing Forces). We must not forget the ceaseless struggle for influence between the Army (IJA: Imperial Japan Army) and the Navy (IJN: Imperial Japan Navy) which also had its own land forces (landing forces identical to the American Marines) . This version was on the other hand intended only for the road
In September 1931 the invasion of Manchuria began, and in these vast expanses devoid of any road network, rail was of paramount importance just as in Russia. Originally equipped with armored trains, the need was quickly felt to have lighter and more responsive vehicles. Note that the reflection was the same in Russia. In addition, the envisaged threats could be supported by this type of vehicle even light. A first prototype was asked to Ishikawajima because this firm had the necessary experience, it was the Sumida type RSW (four wheels) which was deployed in Manchuria. Then the same company proposed to upgrade its Sumida P to develop a mixed rail / road version under the name Ishikawajima PA-type tractor. It is this model that was later produced by Tokyo Gas and Electric Industry under the name type 91 So-Mo (So is for Soko (armored), Mo is unknown). Note that the name armored car is flattering, the Japanese themselves call the types 91 « rail tractors for wide track ». On type 91, there was no fixed machine gun in turret because the army reserved the fixed weapons for the infantry, the artillery and the cavalry, the type 91 being considered as railway vehicle and was used only by the Railway Corps, only the weapons of the soldiers on board were used. In 1933, a small modification made it possible to use a fixed machine-gun in turret. Note that type 93 is a wrong designation used in the west. Note that armor was also removable so we can see photos with unarmored type 91 tractors
On the Japanese name of military vehicles, the situation is very complex because it refers to the reign years of different emperors: Meiji (1867 to 1912), Taisho (1912 to 1926), Hirohito (1926 to 1989). As far as we are concerned, the vehicles were produced during the reign of Emperor Hirohito, but for this period, the year used is that of the Japanese calendar which is 660 years ahead of the western calendar, So, type 91 corresponds to the year 2591 which makes for the Westerners 1931. That’s why one can find type 2591 which is in fact a false appellation. Note that the word « type » is the reference of the year of production, so we can find several totally different vehicles called type 92 for example.
The change of the road / rail wheels was done by removing the full tires or metal bandages and storing them on the sides. For this, the vehicle was lifted via four jacks attached to the front and rear. Normally, it lasted 10 to 20 minutes for the maneuver. The width of the track was not a problem because the spacing could be adapted according to, in fact, the spacing in Manchuria (1435 mm) or China (1524 mm). The So-Mo could not run on the Japan narrower 1372 mm. The speed ranged from 40 km/h on the road to 60 km/h on rail. With the invasion of China in 1937, these vehicles proved their usefulness in monitoring the rail network. Since the vehicle was based on a truck chassis, it only had one speed in reverse, which required it to drive slowly in the event of a recoil, which is why two vehicles were often coupled at the rear in order to move quickly. in both ways. These vehicles were used almost exclusively in China and Manchuria. The crew consisted of six men and a 6.5 mm or 7.7 mm machine gun. The 5mm max armor was sufficient for the type of threats encountered. Note that the production number of 1000 usually used seems very exaggerated compared to the usual Japanese production especially for this type of very particular vehicle and in regards of the needs. It should also be noted that a gas generator kit was provided to the front left of the vehicle.
Characteristics :
Production year: 1931
number: about 1000 (probably exaggerated)
weight: 7 t
length: 6.58 m
width: 1.9 m
height: 2.95 m
crew: 6
armor: 5 mm max
armament: 1 machine gun 6.5 mm or 7.7 mm
engine: 4 cyl gasoline of 45 HP
range: 241 km
speed: 40 km/h on the road / 60 km/h on the rail
