the first thirty locomotives (nos.56001-56030) were built by electroputere in romania, but these suffered from poor construction standards, and many were withdrawn from service early. the remaining 105 locomotives were built by brel at doncaster works (nos.56031 to 56115) and crewe works (nos.56116 to 56135). enthusiasts nicknamed them "grids", likely due to the grid-like horn cover on the locomotive's cab ends. the 'grid' name was given due to the fact that class 56 locomotives were the main motive power used on merry-go-round coal deliveries to national grid power stations.