[5] CIÉ previously maintained a full online list of the twenty five companies which constituted the Great Southern Railways in 1925.

[citation needed] Two companies that were not amalgamated but whose tracks the GSR retained operating rights over were the City of Dublin Junction Railway,[a] and the New Ross and Waterford Extension.

[13] Three railways remained completely outside of the amalgamation process, despite lying wholly within the Free State.

[2] The GS&WR was the dominant constituent in terms of area, route millage and rolling stock.

The former Dublin and South Eastern section in particular had become extremely run down and needed extensive remedial work on its rolling stock with about one-third condemned with immediate effect.

[15] Worldwide economic conditions continued to be difficult and affected Ireland also, passenger and freight revenue decreased to £1.27m and £2.05m by 1939.

[16] Although the Republic of Ireland was a neutral country, railway transport was severely disrupted by The Emergency.

The lack of high-quality coal fuel in Ireland and the need to import from England was severe and desperate alternatives such as turf-burning had only extremely limited success.

1925 records show 526 broad and 41 narrow gauge steam locomotives remaining inherited from the originating companies.

There was a parallel Inchicore scheme that used a letter to indicate the axle layout and a number to designate different groups within the class.

[7] The total number of passenger vehicles including post office, parcel, and brake vans was 1670 in 1925, falling to 1337 by 1944.