43123 was delivered into service on 14 April 1979 and 43065 on 15 October 1977 and both power cars have had their operational life extended by the fitting of MTU power units at Brush Traction, 43123 being the last of the Valenta engine HSTs. Both cars are easily identified by virtue of the buffers that were fitted during the 'surrogate' DVT period and by the fact that they were redesignated as Class 43/4 following their conversion to MTU power. 43123 was renumbered as 43423 on 31 January 2011 and given the name 'VALENTA 1972-2010' on 15 May 2011, while 43065 was renumbered 43465 on 31 December 2010, retaining the name 'City of Edinburgh' that it had first received on 25 February 1996.