The Last Years of the Wee Donegal by Robert Rowbotham and Joe Curran, Colourprint Books, 1998. ISBN 1 898392 43 9. Superb, atmospheric photo-study of the CDR in the 1950's, with track plans of some of the many stations. Very worth looking at for general inspration, even if Irish lines aren't really your thing.
The Wee Donegal Revisited, by Robert Rowbotham and Joe Curran, Colourprint Books,, 2002. ISBN 1 904242 02 2. Slightly less exciting from a landscape and atmposphere point of view, but many good close-ups of rolling stock, with a small number of diagrams included.
The County Donegal Railways Companion - A Handbook for Ralway Modellers and Historians by Roger Cromblehome Midland Pubishing 2005 ISBN 1 85780 2055
An essential guide for anyone wishing to model the County Donegal. With literally dozens of drawings of rolling stock, signals and railway buildings and structures, a well as timetables and operational details. From a modelling perspective this is far and way the most comprehensive book on any Irish railway.
Narrow Gauge Rolling Stock - An Irish Railway Pictorial Desmond Coakham Ian Allan 2007 ISBN 978-0-7110-3194-4. A brilliant collection of good clear photos of rolling stock from may Irish narrow gauge lines. There are a few drawings, but such is the quality of many of the photos, it is possible to make your own. There is also plenty of historical detail on vehicle numbering, suppliers etc. If you are keen on building your own Irish rolling stock, a book to look out for.
Smoke Amongst the Drumlins - The Cavan and Leitrim in the 1950's - Anthony Burges Colourpoint Books 2006 ISBN 1 904242 62 6. A small collection of photos from The C&L in the 1950's. What makes this book a little special is that manages to really capture the atmosphere of the line. Many of the shots just show the railway in the landscape - some without any visible rolling stock (only the inevitable chickens!), If you want to evoke 1950's Ireland this is a real inspiration..
The Irish Narrow Gauge, Vols 1 and 2 - Tom Ferris, Midland Publishing. ISBN 1-85780-010-9 and 1-85780-017-6. A black-and-white pictorial history of all the narrow gauge lines in Eire. Volume One, "From Cork to Cavan," covers the southern lines; Volume Two covers "The Ulster Lines," including the cross-border County Donegal and Londonderry & Lough Swilly. Each chapter covers a different railway and includes sections of OS maps showing the right of way--particularly useful for planning a railway archaeology excursion.
The West Clare Railway - Patrick Taylor, Plateway Press, 1994. ISBN 1 871980 16 X. A thorough history of the last of the Irish narrow gauge lines, with numerous photographs and drawings for the aspiring modeler (though the coach drawings are less than accurate in some critical proportions).
Narrow Line Extra Number Six--The Irish Narrow Gauge; scale drawings described by David Lloyd. 7mm Narrow Gauge Association, 1988. ISBN 0 9513300 0 4. A collection of drawings of Irish narrow gauge locomotives rendered in 7mm scale, mostly steam locomotives, but also many of the Donegal railcars and the West Clare Walker diesel. Most are very good quality, though the Emslie drawings of the C&L locos have some major flaws.
In the Tracks of the West Clare Railway by Edmund Lenihan, The Mercier Press, 1990. ISBN 0 85342 909 X. Edmund Lenihan, storyteller and Clare man, walked the length of the roadbed of the West Clare from Ennis to Kilrush and Kilkee with his son beginning in the winter of 1987. The book describes what they found--not just the remains of the railway, but the memories of the people they met and the stories long told of the land they hiked through.