This part of IS0 8178 specifies the parameters to be applied for the determination of which engine specifications may be included in an engine family and for the selection of the parent engine of the family. This part of IS0 8178 is applicable to reciprocating internal combustion engines for land, rail traction and marine use, excluding engines for motor vehicles primarily designed for on-road operation. It may be applied to engines for power production and/or propulsion in e.g. agricultural equipment, road construction and earth moving machines, industrial trucks, generating sets, etc. _