opinion: Mr. Justice Black
  delivered the opinion of the Court.
  The petitioner, a railroad switchman, was injured while performing duties as an employee of respondents in their railroad coach yard at Denver, Colorado. He brought this action for damages under the Federal Employers’ Liability Act.
  The complaint alleged that in the performance of his duties in the railroad yard it became necessary for him to walk over a wheel-pit on a narrow boardway, and that due to negligence of respondents, petitioner fell into the pit and suffered grievous personal injuries. The complaint further alleged that respondents had failed to furnish him a safe place to work in several detailed particulars, namely, that the pit boardway (1) was not firmly set, (2) was not securely attached, and (3) although only about 20 inches wide, the boardway had been permitted to become greasy, oily, and slippery, thereby causing petitioner to lose his balance, slip, and fall into the pit.
  The respondents in their answer to this complaint admitted the existence of the pit and petitioner’s injuries as a result of falling into it. They denied, however, that the injury resulted from the railroad’s negligence, charging that plaintiff’s own negligence was the sole proximate cause of his injuries. On motion of the railroad the trial judge directed the jury to return a verdict in its favor. The Supreme Court of Utah affirmed, one judge dissenting. -Utah-, 187 P. 2d 188.
  The opinion of the Utah Supreme Court strongly indicated, as the dissenting judge pointed out, that its finding of an absence of negligence on the part of the railroad rested on that court’s independent resolution of conflicting testimony. This Court has previously held in many cases that where jury trials are required, courts must submit the issues of negligence to a jury if evidence might justify a finding either way on those issues. See, e. g., Lavender v. Kurn, 327 U. S. 645, 652-653; Bailey v. Central Vermont R. Co., 319 U. S. 350, 354; Tiller v. Atlantic Coast Line R. Co., 318 U. S. 54, 68; and see Brady v. Southern R. Co., 320 U. S. 476, 479. It was because of the importance of preserving for litigants in FELA cases their right to a jury trial that we granted certiorari in this case.
  The evidence showed the following facts without dispute:
  Petitioner fell into the pit July 26, 1945. The pit, constructed in 1942, ran approximately 40 feet east and west underneath three or more parallel tracks which crossed the pit from north to south. The pit was 11 feet deep and 4 feet 2y2 inches wide with cement walls and floor. Car wheels in need of repair were brought to the pit, lowered into it, there repaired, and then lifted from the pit for return to use. When not in use the pit was kept solidly covered with heavy boards. These boards were used as a walkway by all employees. When the pit was in use the cover boards were removed except one 75 pound “permanent board” 22 inches wide and 4 feet 2% inches long. While the solid covering was off, this “permanent board,” built to fit snugly and firmly, was unquestionably used as a walkway by all employees up to about May 1, 1945.
  On this latter date, the railroad put up “safety chains” fastened to guard posts, inclosing 16% feet of the pit, on its north, south and west sides. The posts, 42 inches high, fitted into tubes imbedded in the ground, the tubes being larger than the posts — enough larger to allow the posts to work freely. The chains, attached 2 inches from the top of the posts, were to be kept up while the pit was in use and taken down when the pit was not in use. They were up when plaintiff slipped from the “permanent board” into the pit. At that time a tourist car was standing over the pit on track “23%.” This track “23%” was east of the two east chain posts, its west rail being about 36 inches, and the tourist car overhang about 7 inches from the two east chain supporting posts. The floor of the “overhang” was about 51 inches above the ground, or 9 inches above the top of the posts, thus allowing an unobstructed clearance of 51 inches under the overhang. The “permanent board” was inside the chain enclosure, the board’s east side being about 9% inches from the two eastern chain posts. Despite the proximity of the tourist car to the posts there was sufficient space east of each chain post so that pit workers had access to and used the board as a walkway. One of the defendant’s witnesses, a very large man weighing 250 pounds, passed through it, though according to his testimony, with “very bad discomfort.” Petitioner was a much smaller man, weighing 145 pounds, and it was by passing between one of these posts and the tourist car that petitioner reached the “permanent board” which bridged the pit. Oil from wheels would sometimes accumulate at the bottom of the pit, and as stated by the Utah Supreme Court the “permanent board” was “almost certain to become greasy or oily” from use by the pit-men.
  Neither before nor after the chains were put up had the railroad ever forbidden pit workers or any other workers to walk across the pit on the “permanent board.” Neither written rules nor spoken instructions had forbidden any employees to use the board. And witnesses for both sides testified that pit workers were supposed to, and did, continue to use the board as a walkway after the chains and posts were installed. The Utah Supreme Court nevertheless held that erection of the chain and post enclosure was itself the equivalent of company orders that no employees other than pit workers should walk across the permanent board when the chains were up. And the Utah Supreme Court also concluded that there was insufficient evidence to authorize a jury finding that employees generally, as well as pit workers, had continued their long-standing and open practice of crossing the pit on the permanent board between the time the chains were put up and the time petitioner was injured.
  It is the established rule that in passing upon whether there is sufficient evidence to submit an issue to the jury we need look only to the evidence and reasonable inferences which tend to support the case of a litigant against whom a peremptory instruction has been given. Viewing the evidence here in that way it was sufficient to show the following:
  Switchmen and other employees, just as pit workers, continued to use the permanent board to walk across the pit after the chains were put up as they had used it before. Petitioner and another witness employed on work around the pit, testified positively that such practice continued. It is true that witnesses for the respondents testified that after the chains were put up, only the car men in removing and applying wheels used the board “to walk from one side of the pit to the other . . . .” Thus the conflict as to continued use of the board as a walkway after erection of the chains was whether the pit workers alone continued to use it as a walkway, or whether employees generally so used it. While this left only a very narrow conflict in the evidence, it was for the jury, not the court, to resolve the conflict.
  It was only as a result of its inappropriate resolution of this conflicting evidence that the State Supreme Court affirmed the action of the trial court in directing the verdict. Following its determination of fact, the Utah Supreme Court acted on the assumption that the respondents “had no knowledge, actual or constructive, that switchmen were using the plank to carry out their tasks,” and the railroad had “no reason to suspect” that employees generally would so use the walkway. From this, the Court went on to say that respondents “were only required to keep the board safe for the purposes of the pit crewmen . . . and not for all the employees in the yard.” But the court emphasized that under different facts, maintenance of “a 22-inch board for a walkway, which is almost certain to become greasy or oily, constitutes negligence.” And under the evidence in this case as to the board, grease and oil, the court added: “It must be conceded that if defendants knew or were charged with knowledge that switchmen and other workmen generally in the yard were habitually using the plank as a walkway in the manner claimed by plaintiff, then the safety enclosure might be entirely inadequate, and a jury question would have been presented on the condition of the board and the adequacy of the enclosure.”
  We agree with this last quoted statement of the Utah court, and since there was evidence to support a jury finding that employees generally had habitually used the board as a walkway, it was error for the trial judge to direct a verdict in favor of respondents.
  There was, as the state court pointed out, evidence to show that petitioner could have taken a slightly longer route and walked around the pit, thus avoiding the use of the board. This fact, however, under the terms of the Federal Employers’ Liability Act, would not completely immunize the respondents from liability if the injury was “in part” the result of respondents’ negligence. For while petitioner’s failure to use a safer method of crossing might be found by the jury to be contributory negligence, the Act provides that “contributory negligence shall not bar a recovery, but the damages shall be diminished by the jury in proportion to the amount of negligence attributable to such employee . . . .”
  Much of respondents’ argument here is devoted to the proposition that the Federal Act does not make the railroad an absolute insurer against personal injury damages suffered by its employees. That proposition is correct, since the Act imposes liability only for negligent injuries. Cf. Coray v. Southern Pac. Co., 335 U. S. 520. But the issue of negligence is one for juries to determine according to their finding of whether an employer’s conduct measures up to what a reasonable and prudent person would have done under the same circumstances. And a jury should hold a master “liable for injuries attributable to conditions under his control when they are not such as a reasonable man ought to maintain in the circumstances,” bearing in mind that “the standard of care must be commensurate to the dangers of the business.” Tiller v. Atlantic C. L. R. Co., 318 U. S. 54, 67.
  There are some who think that recent decisions of this Court which have required submission of negligence questions to a jury make, “for all practical purposes, a railroad an insurer of its employees.” See individual opinion of Judge Major, Griswold v. Gardner, 155 F. 2d 333, 334. But see Judge Kerner’s dissent from this view at p. 337 and Judge. Lindley’s dissenting opinion, pp. 337-338. This assumption, that railroads are made insurers where the issue of negligence is left to the jury, is inadmissible. It rests on another assumption, this one unarticulated, that juries will invariably decide negligence questions against railroads. This is contrary to fact, as shown for illustration by other Federal Employers’ Liability cases, Barry v. Reading Co., 147 F. 2d 129, cert. denied, 324 U. S. 867; Benton v. St. Louis-San Francisco R. Co., 182 S. W. 2d 61, cert. denied, 324 U. S. 843. And cf. Bruner v. McCarthy, 105 Utah 399, 142 P. 2d 649, cert. dismissed for reasons stated, 323 U. S. 673. Moreover, this Court stated some sixty years ago when considering the proper tribunal for determining questions of negligence: “We see no reason, so long as the jury system is the law of the land, and the jury is made the tribunal to decide disputed questions of fact, why it should not decide such questions as these as well as others.” Jones v. East Tennessee R. Co., 128 U. S. 443, 445. And peremptory instructions should not be given in negligence cases “where the facts are in dispute, and the evidence in relation to them is that from which fair-minded men may draw different inferences.” Washington & G. R. Co. v. McDade, 135 U. S. 554, 572. Such has ever since been the established rule for trial and appellate courts. See Tiller v. Atlantic C. L. R. Co., 318 U. S. 54, 67, 68. Courts should not assume that in determining these questions of negligence juries will fall short of a fair performance of their constitutional function. In rejecting a contention that juries could be expected to determine certain disputed questions on whim, this Court, speaking through Mr. Justice Holmes, said: “But it must be assumed that the constitutional tribunal does its duty and finds facts only because they are proved.” Aikens v. Wisconsin, 195 U. S. 194, 206.
  In reaching its conclusion as to negligence, a jury is frequently called upon to consider many separate strands of circumstances, and from these circumstances to draw its ultimate conclusion on the issue of negligence. Here there are many arguments that could have been presented to the jury in an effort to persuade it that the railroad’s conduct was not negligent, and many counter arguments which might have persuaded the jury that the railroad was negligent. The same thing is true as to whether petitioner was guilty of contributory negligence. Many of such arguments were advanced by the Utah Supreme Court to support its finding that the petitioner was negligent and that the railroad was not. But the arguments made by the State Supreme Court are relevant and appropriate only for consideration by the jury, the tribunal selected to pass on the issues. For these reasons, the trial court should have submitted the case to the jury, and it was error for the Utah Supreme Court to affirm its action in taking the case from the jury.
  It is urged by petitioner that other fact issues should have been submitted to the jury in addition to those we have specifically pointed out. We need not consider these contentions now since they may not arise on another trial of the case.
  The judgment of the Supreme Court of Utah is reversed and the cause is remanded for further action not inconsistent with this opinion.
  It is so ordered.
  35 Stat. 65 as amended by 36 Stat. 291 and 53 Stat. 1404, 45 U. S. C. §§ 51-59.
  There was evidence that other types of cars had a wider overhang thereby reducing the space available for passage between the posts and the car. This evidence bore directly on the fact question as to the practice of employees generally in using the boardway as petitioner did here.
  Petitioner testified in part as follows:
  “Q. Mr. Wilkerson, I will ask you to state whether or not you have ever observed other switchmen or workmen working in the yards there in passing over that pit while cars were standing on 23% since the safety chains were up ?
  “A. Yes, sir, I have.
  “Q. What has that practice been, the practice of crossing over the pit?
  “A. Men that work around there, regardless of whether switchmen or car men that wanted to go that way went through there.
  “Q. Went through — you mean over the pit?
  “A. Over that pit, as I just described, from either side.
  “Q. I will ask you to state whether or not you observed any practice with reference to crossing over the pit when men were working on the cars there in the daytime before these chains were installed?
  “A. Walked right straight across the board.
  “Q. Was there a board usually there to walk over ?
  “A. Yes, sir.
  “Q. Was there any change in that practice after the chains were installed?
  “A. None, only they had to walk around the chains.
  “Q. What did you observe with reference to the number of times the occasions when men would cross over the pit.
  “A. Oh, I couldn’t say; I suppose maybe a hundred times; varies, men, both switchmen and car men or others working there in the yard necessary, pullman, employees and so forth.
  “Q. Crossed over the pit?
  “A. Yes, sir, it was a common practice for everybody to use that that way.
  “Q. Did you ever see — did you ever notice the board ever being used for any other purpose except men walking across ?
  “A. No, sir, I haven’t.
  “Q. Ask you to state whether or not you experience any difficulty in passing between the ear and the post and onto the board and over the board and between the car and the north post at the time you passed it, the first time in the morning?
  “A. No.”
  Another witness testified in part as follows:
  “Q. And what have you noticed with reference to the practice of men passing between the standing cars on 23% and the posts that hold the safety chains ?
  “A. Well, they would walk through and get on the board and walk to and from each side, and the men that work on the pit work on that board, and sometimes set on the board next to the— in next to the car there to perform their work, you know, like where they are up under, or working on the car, they use the board over from it to work on.
  “Q. What has been your practice in passing between cars that are standing on 23% and the posts that hold the stakes and chains when they have been in place ?
  “A. When I have occasion to pass through there, I put my hand on the post, step over on the board, and go around the other post, and that is the way I pass to and from on the pit.
  “Q. Have you observed other men passing over the pit under similar circumstances?
  “A. Yes, sir, I have.
  “Q. And what can you say with reference to the — such occurrences, as to how often they happen ?
  “A. O, I would judge that I saw the men pass through there dozens of times. . . .
  “Q. Have you seen any other switchman working there in the yards act similarly; that is, go around the post, between the post and the car and pass over the board?
  “A. Yes, sir, I have saw my helpers at different times and before the chains were placed, we used the board at all times, you know, just to cross the pit. I have walked across the pit a number of times that way, and also my helpers.”
  This witness later gave the names of two switchmen he had seen cross after chains were put up, but he did not thereby qualify his testimony previously given as to the practice of employees generally to use the walkway.
  The state court argued that “other and safer routes were open” to the petitioner. But contributory negligence does not exempt a railroad from liability for its own negligence.
  The state court also advanced the following argument: “In this particular case, the board appears adequate for the use of the pit crewmen, but entirely inadequate if intended to be a cross-walk for other employees. Employees climbing in and out of the pit approach more deliberately, use other and different hand holds, and are more careful of their footing, while employees swinging on to the plank in a hurry are apt to forget about the slippery condition of an oily board and forget about the dangers incident to crossing, as did the plaintiff, who swung himself around the chain post and onto the plank.” Aside from the apparent absence of direct evidence that pit crewmen would exercise greater care to protect themselves than would other employees, whether they would or not is patently a jury question.
  The state court also said: “Had they not intended to preclude the use of the board as a walk-way, the defendants would not have installed the chain posts so as to block an open straight approach to the board.” This argument of the state court ignores the absence of any direct evidence to show that the chains were erected to keep people from walking over the old “permanent board” walkway. Petitioner testified that it was his understanding that the chains were erected “to keep people from walking directly into the open pit.”
  Another argument of the State Supreme Court was: “Also, a sign not to cross would have afforded plaintiff no additional security or warning, for he disregarded the chain and he would no doubt have ignored another form of warning.” If such an inference was justifiable and was relevant at all on the question of railroad negligence, it was an inference to be drawn from facts by the jury, not by the court.