Type 91 Armored Railroad Car "So-Mo"
- Introduced Year : 1930
- Weight : 7 ton
- Dimensions: 6.58 x 1.9 x 2.95(h) m
- Armor (max) : 6 mm
- Speed (max) : 40 km/hr (ground), 60km/hr (railroad)
- Engine : Gasoline Engine 50 HP
- Armaments : No fixed weapons. Crews carried a rifle or a machine gun.
- Crew : 6
- Production Qty : 1,000
Type 91 Armored Car could run on both railway and road by changing wheels. It was used in order to guard railways in Manchuria by railway engineers.