delivered the opinion of the court.

The deceased, Fetta, was at work in the repair yard of a railroad; other servants of the road, an engine and switching crew, ran a car needing repair from the general tracks into the special yard, and by their negligence killed him. There was no further relation between the parties than these facts disclose, and the question is certified whether they were fellow-servants within the rule that would exempt the railroad from liability in that case.

The doctrine as to fellow-servants may be, as it has been called, a bad exception to a bad rule, but it is established, and it is not open to courts to do away with it upon their personal notions of what is expedient. So it has been decided that in cases tried in the United States courts we must follow our own understanding of the common law when no settled rule of property intervenes. Kuhn v. Fairmont Coal Co., 215 U. S. 349. Northern Pacific R. R. Co. v. Hambly, 154 U. S. 349, 360.

The precedents in this court carry the doctrine as far as it is necessary to carry it in this case to show that the two persons concerned were engaged in a common employment. No testimony can shake the obvious fact that the character of their respective occupations brought the people engaged in them into necessary and frequent contact, although they may have had no personal relations. Every time that a car was to be repaired it had to be switched into the repair yard. There is no room for the exception to the rule that exists where' the negligence consists in the undisclosed failure to furnish a safe place to work in, an exception that perhaps has been pushed to an extreme in the effort to limit the rule. Santa Fe Pacific R. R. Co. v. Holmes, 202 U. S. 438. McCabe & Steen Construction Co. v. Wilson, 209 U. S. 275. The head of the switching crew and the deceased were as *89 clearly fellow-servants as the section hand and engineer in Texas & Pacific Railway Co. v. Bourman, 212 U. S. 536. Northern Pacific R. R. Co. v. Hambly, 154 U. S. 349. It may be that in the state court the question would be left to the jury, Gathman v. Chicago, 236 Illinois, 9; Indiana, Illinois & Iowa R. R. Co. v. Otstot, 212 Illinois, 429, but whether certain facts do or do not constitute a ground of liability is in its nature a question of law. To leave it uncertain is to leave the law uncertain. If the law is bad the legislature, not juries, must make a change. We answer the certificate, Yes..