Catalyzes the folate-dependent formation of 5-methyl-uridine at position 54 (M-5-U54) in all tRNAs. (6R)-5,10-methylene-5,6,7,8-tetrahydrofolate + H(+) + NADH + uridine(54) in tRNA = (6S)-5,6,7,8-tetrahydrofolate + 5-methyluridine(54) in tRNA + NAD(+) (6R)-5,10-methylene-5,6,7,8-tetrahydrofolate + H(+) + NADPH + uridine(54) in tRNA = (6S)-5,6,7,8-tetrahydrofolate + 5-methyluridine(54) in tRNA + NADP(+) Belongs to the MnmG family. TrmFO subfamily.