In Donnelly v. Southern Pacific Co. (1941) 18 Cal.2d 863, the plaintiff was injured in a train collision while traveling on a free pass provided to the spouses of the defendant's employees. The pass contained a provision that the defendant would not be liable under any circumstances for any injury incurred by the user of the pass. The evidence showed that the collision occurred when an employee improperly set a switch. The jury was instructed that the plaintiff could recover only for gross negligence. After a plaintiff's verdict the defendant appealed. The California Supreme Court noted that federal law applied and that under federal law a railroad could contract to release itself of liability for negligence, but not for willful and wanton negligence. It was thus necessary to determine what was meant by willful and wanton negligence. In this connection the court explained: "Negligence is an unintentional tort, a failure to exercise the degree of care in a given situation that a reasonable man under similar circumstances would exercise to protect others from harm. A negligent person has no desire to cause the harm that results from his carelessness , and he must be distinguished from a person guilty of willful misconduct, such as assault and battery, who intends to cause harm. Willfulness and negligence are contradictory terms. If conduct is negligent, it is not willful; if it is willful, it is not negligent. It is frequently difficult, however, to characterize conduct as willful or negligent. A tort having some of the characteristics of both negligence and willfulness occurs when a person with no intent to cause harm intentionally performs an act so unreasonable and dangerous that he knows, or should know, it is highly probable that harm will result. Such a tort has been labeled 'willful negligence,' 'wanton and willful negligence,' 'wanton and willful misconduct,' and even 'gross negligence.' It is most accurately designated as wanton and reckless misconduct." ( Donnelly, supra, at p. 869.) The court found no sufficient evidence of wanton and reckless misconduct, and thus reversed the judgment. ( Id., at p. 872.)