A Queens bus driver was arraigned today on disturbing charges that he repeatedly sexually assaulted three elementary school girls between the ages 7 and 9. Nelson Painchault, 69, was charged with 18 counts of sexual abuse and three counts of endangering the welfare of a child. Prosecutors allege that he continually touched the girls' private parts numerous times between Sept. 9 and Nov. 3. Painchault was fired from Adrilliz Transport this month after working as a private contractor for them for 11 years; his bus route this year included two elementary schools in Corona. He was held on $100,000 bail.