EE had exited cab of Komatsu excavator. EE turned & was holding the handrails to dismount. EE dropped EE's right foot to step on the step. Right foot slipped & went to the ground while EE's left foot remained on the track due to EE's boot catching on the track. During the slip EE held onto the handrail with left hand, overextending left leg & sustained a strain to thigh muscle.