To maintain a true pocket size book technical information which is duplicated or readily available elsewhere (eg. Wikipedia) is left out, just the key data for locomotive and multiple unit train classes is provided.
The listing of locomotives and units details of numbers, names, owner/operators, shed allocations and any specific differences between class members. Multiple unit train formations are listed, allowing unit numbers to be identified from individual car numbers. The small number of locomotive hauled passenger coaches and the fleet of HST coaches are listed with number, allocation and any previous number for vehicles modified/rebuilt/renumbered, plus detail variations from similar vehicles.
The 2020 book retains the enlarged 160 page count needed to accommodate the large number of new EMU trains being delivered for the Great Western electrification, TfL Overground, Crossrail and other services which are supplementing rather than replacing existing trains.