| O'Mara, John A.; 1899 Red Book; 1899 | 1899 Red Book | 1899-00-00 | NORTHERN KING | Chief Engineer |
| O'Mara, John A.; 1901 Red Book; 1901 | 1901 Red Book | 1901-00-00 | NORTHERN KING | Chief Engineer |
| O'Mara, John A.; 1902 Red Book; 1902 | 1902 Red Book | 1902-00-00 | NORTHERN KING | Chief Engineer |
| O'Mara, John A.; 1903 Red Book; 1903 | 1903 Red Book | 1903-00-00 | NORTHERN KING | Chief Engineer |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | CONEMAUGH | Oiler |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | GORDON CAMPBELL | Oiler |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | CONEMAUGH | Oiler |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | FRED MERCUR | First Assistant |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | CLYDE | First Assistant |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | H. E. PACKER | First Assistant |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | CLYDE | First Assistant |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | VIRGINIA | First Assistant |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | OSWEGO | First Assistant |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | FRED MERCUR | First Assistant |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | CHEMUNG | First Assistant |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | NORTH STAR | First Assistant |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | NORTH STAR | Chief Engineer |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | NORTH STAR | Chief Engineer |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | NORTH STAR | Chief Engineer |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | NORTH STAR | Chief Engineer |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | NORTHERN KING | Chief Engineer |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | NORTHERN KING | Chief Engineer |
| O'Mara, John A.; Mansfield, 1899 | Mansfield, 1899 | 1899-00-00 | NORTHERN KING | Chief Engineer |