Catalysis of the reaction: adenosine57/adenosine58 in tRNA + 2 S-adenosyl-L-methionine = 2 H+ + N1-methyladenosine57/N1-methyladenosine58 in tRNA + 2 S-adenosyl-L-homocysteine.
tRNA (adenine-57, 58-N(1)-) methyltransferase activity