Question on BJ's WW1 mod

Now, my question is a thing that bugged me for a long while and it is what is the best anti-tank weapon in the game. Now I use Submarines, Siege Artillery,Armoured Train, Bombers and other Aircraft. Now each has it's flaws. First the Submarine, it's simple, it can knock out a tank but it can only attack if the Tank is on water or on a coastal province. Siege Artillery, well now there are 2 sub categories for this, the regular buildable ones, or the special Artillery like the Paris Gun or the Russian whatever. Well the buildable one outranges and does decent enough dammage but it can be dammaged by the Tsar tank and it is too weak as in HP. Armoured Train has proven to be the most harsh on the offensive but easily overrun and to be dammaged even with a general, and plus the small mobility. Bombers and Aircraft are pretty safe with range being afar and their HP doesn't matter much when they are afar but they do not deal that much dammage to the tank even with an Ace on it.