The invention relates to a vehicle or machine (1 ) suitable for operation on uneven or inclined surfaces, the vehicle or machine being a forest work unit and comprising at least three frame parts (2, 3, 4) and two rotational planes (A, B), each of which rotational planes (A, B) is arranged to be formed, in each particular case, on an interface between two successive frame parts (2, 3, 4) of the vehicle or machine (1 ). The rotational planes (A, B) are, in each particular case, planes perpendicular to the longitudinal axis (C) of the vehicle or machine (1 ) in the neutral position. Said frame parts (2, 3, 4) are thus arranged to be mutually rotatable in relation to said rotational plane (A, B).
