The class 57 locomotives were rebuilt by Brush between 1997 and 2004 for Freightliner. Class 47s were used to supply a core bodyshell with the 47s Sulzer engine and generator being replaced by a 12 cylinder EMD 645 engine allied to a refurbished Brush alternator recovered from withdrawn class 56 locomotives. Freightliner subsequently opted to order new class 66 locomotives to expand their fleet and as sufficient of the new locomotives entered service the 57s were sold on to other operators. DRS currently roster 9 of them, though most are usually stored serviceable ready for use on a 'spot hire' basis.