 As a result, it was decided that steel bodywork and cab sections could be welded directly to the chassis in places mainly for ease of construction and consequently adding additional stability to the chassis in a similar fashion to that of a coachbuilder converting an 'open' model.It should be stressed that this welded bodywork was not essential for maintaining acceptable levels of torsional chassis strength, the chassis design of the 'closed' back models should not be considered as 'unitary' for this reason.The correct definition in this case is a 'body reinforced separate chassis'.