(a) This account must include the cost of power operated equipment used in construction or repair work exclusive of equipment includible in other accounts. Include, also, the tools and accessories acquired for use with the equipment and the vehicle on which the equipment is mounted.

(b) This account must include the following items:

(1) Air compressors, including driving unit and vehicle.

(2) Back filling machines.

(3) Boring machines.

(4) Bulldozers.

(5) Cranes and hoists.

(6) Diggers.

(7) Engines.

(8) Pile drivers.

(9) Pipe cleaning machines.

(10) Pipe coating or wrapping machines.

(11) Tractors—Crawler type.

(12) Trenchers.

(13) Other power operated equipment.

(c) It is intended that this account include only the large units that are generally self-propelled or mounted on movable equipment.