The ‘Rail Blue’ colour scheme dominated Britain’s Railways for almost twenty years and at the time was considered some what drab and lifeless, especially when compared with the colourful variety of livery styles which had appeared on many of the new diesel and electric locomotive types since their introduction in the 1950s and 1960s. However, it is now clear that what the fleet may have lacked in colour, it certainly made up for in variety, as during those ‘blue years’ and compared to today, a host of different classes were to be witnessed plying their trade all over the country on a wide range of freight, passenger and parcels workings. This latest volume in the ‘BR Blue’ series, compiled by Gordon Wright, concentrates on the diesel classes within the ‘Type 4’ power range and includes such favourites as the Class 40 ‘Whistlers’, the Class 44 -46 ‘Peaks’, the much mourned ‘Western’ and ‘Warship’ hydraulics, the ever popular Class 50 ‘Hoovers’ and the ubiquitous ‘Brush’ Class 47s. In addition, the locations featured are just as varied, with locomotives to be seen in busy urban station platforms as well as remote rural settings: all the way from Wales to East Anglia and from Scotland to Cornwall. All of the above helps to create a fitting celebration of a time which, in retrospect, is now seen to be one of the most interesting and enjoyable on Britain’s Railways.