There are 9 Doherty's in Mullingar, Co. Westmeath in the WM telephone book. You could use the addresses given to write to these folks. None were on Barrack St.
1911 Census. www.census.nationalarchives.ie
#11 Barrack St. Mullingar, North Urban.
Michael 50, born Meath, Bailiff
Eliza 45, wife born Meath, married 30 yr. 7 born 6 living
Mary 25, also born Meath, general servant
Rose 17, also born Meath, general servant
John 11 school born Meath
Michael 10 school born Meath
Philiomena 7 born Meath