This detail is pretty weird but it was also shown in Das Finale so it must be canon. If we imagine that Senshadou was founded after WW1 (1918) or WW2 (1945), since Tank has only been a thing from WW1The Winter Continuous Track Cup poster contains very important information.
Among the sponsors is "Senshado 200th anniversary planning committee", which places the story at least 200 years after our time.
This is the most accurate time marker so far.