Since there isn't much basic information on this thread I thought I might provide some background from Tourret's book.
The design was from the Sudan railway 220 class of which 16 (220-235) had been built pre WWII by North British.
An additional 55 locomotives were built in 1942 by NBL for the WD, Contract L939, builder's numbers 24816 to 24870.
These had WD numbers 2800 to 2854, later 72800 to 72854.
Only 25 locomotives were used during WWII, becoming Sudan 236 to 260
10 additional locomotives sent to Africa but not used were taken into stock by the Sudan GR in 1946 and 1947, numbers 261 to 270
Of the remaining 20 locomotives which had been stored in the UK, 14 became WAGR U class and 6 went to the Trans Zambesia Railway as Class F, numbers 25 to 30.
Tourret reported that ten locomotives were still in use on the SGR in 1983, with many others stored.
I believe that some locomotives were repaired during the 1990s in an attempt to restore services during a relatively peaceful period.