 After being an unused substitute for Leinster's inaugural Railway Cup win in 1927, O'Reilly was the first-choice full-back by 1932.He won his first Railway Cup medal on the field of play that year following a 6-8 to 4-4 defeat of Munster.The province made it two-in-a-row the following year, and a 4-6 to 3-6 defeat of Munster gave O'Reilly a second Railway Cup medal.