| ID | Route | Notes |
|---|
| A | Portarlington - Athlone East Jcn | |
| B | Dublin - Dundalk - border | Belfast line? |
| C | Dublin - Cork - Cobh | |
| D | | |
| E | Limerick - Ennis - Athenry - Claremorris | |
| F | Limerick Check - Foynes | |
| G | Dublin - Mullingar - Athlone - Galway | |
| H | Waterford - Rosslare Harbour | |
| I | | |
| J | New Ross - Abbey Jcn | |
| K | Drogheda - Navan - Kingscourt | |
| L | Limerick - Tipperary - Waterford | |
| M | Athlone West Jcn - Claremorris - Westport | Mayo line |
| N | Ballybrophy - Nenagh - Killonan Jcn | |
| O | Dublin docks | |
| P | | |
| Q | Howth Jcn - Howth | |
| R | Dublin - Wexford - Rosslare Strand | |
| S | Mullingar - Sligo | |
| T | Killarney Jcn - Killarney - Tralee | |
| U | Cement Factory Jcn - Castlemungret | |
| V | Tralee - Fenit | |
| W | Cherryville Jcn - Kilkenny - Waterford | |
| X | Manulla Jcn - Ballina | |
| Y | Glounthaune jcn - Youghal | |
| Z | | |