Between 1956 and 1958, Córas Iompair Éireann built the 19 Maybach engined locomotives of class E401. These were intended to be six axle light mixed traffic locomotives and were fitted with the Maybach MD220, rated at 420hp. The transmission was the Mekydro KL64. Originally designed to run at up to 60mph, they were quickly limited to 25mph due to poor riding caused by the odd axle spacing. The locomotives were numbered E401-E419.
In 1962 Córas Iompair Éireann took delivery of the first 14 examples of an improved version of the E401. The 420hp MD220 was again used, although the transmission was the KL64u. These locomotives were classed as E421 and numbered from E421-E434. The most visible difference between the E401 and the E421 is the lack of an exhaust silencer hump on the E421. The E421's suffered the same riding problems as the E401's and were also restricted to 25mph.
There are some line drawings and more info, as well as modelling hints and tips on "Steve Johnsons Railway Pages":
http://website.lineone.net/~sjohnson40/Loco%20Profiles/EClass.html
Three E421'a are preserved: two on the Downpatrick Railway Museum's railway at Downpatrick, County Down, Northern Ireland, E421 & E432, and E428 preserved privately at CIE's main works at Inchicore, Dublin.
http://www.downrail.co.uk/locos.htm
In the early 1960's, CIE was looking for a solution to the problems they were having with their Crossley engined Metro-Vick locomotives. In 1965, they removed the 550hp Crossley V8's from two of their C class locomotives and replaced them with Maybach MD650 engines, which were derated to 980hp at 1200rpm to match the rotational limits of the existing M-V generator. The locomotives involved with this experiment were C233 & C234. Once re-engined they were reclassified as B class locomotives. While the Maybach re-engining was a success the programme was not continued across the remaining 32 C class locomotives as CIE really wanted General Motors engines to replace the Crossley engines. This finally happened between 1969 & 1972. Finally, 233 & 234 were re-engined with GM 8-645E engines in 1980 & 1979 respectively. All of what were originally the C class were withdrawn from CIE service between 1983 & 1986. 233 & 234 lasted about 5 years with their "new" GM engines.
The Irish Traction Group have preserved a C class, although it is obviously fitted with a GM engine, you can get an idea of what the loco looked like. Fourth photo down, C231 in green. The photo of A3R has the cab end of Maybach engined E428 visible in the background.
http://members.lycos.co.uk/MarkMaidment/itgpix.htm
On 17th April 2005, E421 worked as part of a special ITG organised running day on the Downpatrick Railway. Paul Fergusson kindly supplied this report:
"Ex- CIE Maybach engined E Class Diesel Hydraulic worked on the Downpatrick Railway last Sunday as part of a Special operating day organised by the Irish Traction Group (ITG). The lines two G-Class Deutz Diesel Hydraulics also worked. It is believed to be the first time E421 has worked since 1996. It hauled the 1600 and 1640 return workings from Downpatrick and performed very well with much thrash and clag being in evidence, despite the shortness of the line (two 1 mile branches).Earlier in the day it had seemed likely it wouldn't run but it received some hasty fitters attention and ran without problems.
For you info, E432 is also at Downpatrick unserviceable at present. E428 is at Inchicore and in good condition. It has been bought by someone who wanted to run it at his home (!). Unfortunately apparently he then redesigned his Garden or drive in such a way that it now cannot be delivered! This is the story we were told anyway...."