I would rather classify that as a Textura/Gothic, not a Fraktur (quadratic 'serifs', form of sc 'o', 'ö', 'r'). I think I have seen this logo in an ad in a telephone book of Vienna 1924, so it is probably hard to find their 'font' (if it is not custom, which I could imagine, sure based on letterforms). Their website does not give any hints on the logo or since when it is in use. Perhaps they can help you if you ask politely?