Alison,
Derryola is about a mile south of Redhills station on the line from Clones to Cavan which closed in 1957, but it isn’t far from Ballyhaise either (They were only about 2 miles apart). Ballyhaise used to be called Belturbet Junction till it was renamed in 1885. George could have worked at either station, but obviously McCoy’s information points to Belturbet Junction/Ballyhaise. His employer seems likely to have been the Great Northern Railway (Ireland), as they owned that line. See map attached, taken from Johnsons Atlas & Gazetteer of the Railways of Ireland.
The 1922 timetable for the line lists 4 trains each way per day (none on Sundays). There was also a shuttle service from Ballyhaise to Belturbet. Again 4 a day. So it doesn’t sound as though he would have been rushed off his feet.
I found a photo of Ballyhaise taken in August 1956 by the late Gerry Douglas. It features in Tom Ferris’s book “Irish Railways in Colour.” The big house on the hill behind the station looks to have been built in the same style as the station (similar chimneys and similar crossed wooden bits). I wondered if perhaps that was the stationmaster’s house. (Though obviously if George lived in Derryola, then it can’t have been his home).