Wheel motors of HTK240 caught fire. Operators cleared truck; sustained no injuries. WTK applied approx 2000 gallons of water. Fire was not able to be extinguished completely. MSHA hotline was called at 30 minutes. EE called back with instructions to seize extinguishing efforts, evacuate area, issue J Order 9613334. Quantification of damage-No injuries/Property damage HTK240