The German giant mortar Mörser Karl Gerät Nr. III to Odin, used against the Soviet fortress of Brest, in the early stages of Operation Barbarossa in June 1941. Beside's the Munitionsschlepper (ammunition loader), PzKpfw IV converted.
T-46 was developed in an attempt to improve the mobility of the T-26. T-26 suspension consisted of eight small road wheels carried in pairs on small bogies. The bogies were supported in pairs by leaf springs. This was less effective than the Christie suspension used on the BT series of fast tanks, and so in 1935, S. Ginzburg of the OKMO team at Zavod No.185 was ordered to produce a new version of the T-26 using the Christie suspension. A small production run of seventy tanks was planned.