The Dagsboro VFD was alerted for a reported vehicle fire at the NRG Power Plant. E731 under the command of Capt. J. Marvel responded with a staffing of 5. E731 was advised that a large bulldozer was reported on fire at the top of coal pile #4. Crews arrived to find the scene as reported with the bulldozer well off. Brush 73 arrived & sent up the coal pile to get a size up & begin fire attack, while NRG personnel & IC looked for a way to get the engine to the top. Brush 73 made its way to the top & began fire attack operations, knocking the baulk of the fire. Once an access was found for E731 & E732 crews began foam operations. Crews operated for over 2 hrs as metal plates had to be removed to get to the hydraulic pumps & lines. Once crews gained access to the hydraulic area the remaining fire was extinguished & fuel tank & hydraulic tanks cooled. The bulldozer was a total loss.