Opinion by
Mb. Justice Chidsey,In this action of trespass the plaintiffs, Frank A. Scibelli, by his father and guardian, Joseph A. Scibelli, and Joseph A. Scibelli and Marion Scibelli in their own right, sought to recover damages for injuries sustained by the minor plaintiff when he attempted to steal a ride on the defendant’s train. The jury returned a verdict in favor of the minor plaintiff for $14,500 and for his parents in the sum of $7,500. The defendant filed a motion for a new trial which was withdrawn and a motion for judgment non obstante veredicto which the court granted. Plaintiffs appeal from the entry of the judgment for defendant.
For a proper understanding of the issue involved it becomes essential to depict the locus in quo. The defendant, Pennsylvania Railroad Company, operated a single track spur line through the City of Lebanon, Pennsylvania between its yards at Twelfth Street and the plant of the Bethlehem Steel Company east of its yards. The tract of land where the accident occurred, colloquially termed “The Willows”, is bounded on the east by Seventh Street, on the west by Eighth Street and on the south by Willow Street. A short distance west of and parallel to Seventh Street lies Chapel Street which leads into and comes to an end at Willow Street.
The Willows is. an open area but there are residences and other buildings on both Eighth Street and Willow Street, the rear of which buildings face the open area. The Quittapahilla Creek flows in an east-west direction approximately in the center of The Willows. The defendant owned all of The Willows south of Quittapahilla Creek, and on January 16, 1951 leased all of this land with the exception of its spur line and right-of-way to parties known as Altenderfer and Mar-*284got. North of the creek the defendant also owned land which its spur line traversed, although most of The Willows north of the track belonged to the Beading Company.
Tracing the spur line in the direction the train moved on June 25, 1951, the day of the accident, it proceeded westwardly parallel to Willow Street and as it crossed Chapel Street curved to the right into The Willows in a northwesterly direction. Proceeding on this course through The Willows it crossed a railroad bridge over the Quittapahilla Creek, continued in a northwesterly direction and then curved to the left to intersect Eighth Street. The track may be considered as constituting an elongated “S” with the western end at Eighth Street and the eastern end at Chapel Street where the latter intersects Willow Street, a distance of 762% feet.
The testimony offered by the plaintiffs which must be interpreted most advantageously to them discloses that on June 25, 1951 the minor plaintiff, who was seven years of age, along with several other children, was playing in the vicinity of a group of mulberry trees which grow a short distance east of the spur line on the south side of the creek. At about 2 P.M. the defendant’s train, consisting of eleven cars drawn by a diesel shifter engine, entered The Willows from the east, travelling about as fast “as a person could walk”. The last three cars were empty low flat cars with built-up ends and no sides, commonly designated as billet cars. All five members of the crew were in the cab of the diesel engine. As the diesel passed the children they were on the south bank of the creek west of the track picking mulberries. Nellie Croesus, age 12, a cousin of the minor plaintiff, held onto his shirt as the locomotive went by and then thinking that the children would continue picking mulberries, she released him. After most *285of the train passed the children, it came to a momentary-stop near the Eighth Street intersection, with at least three of its cars on the same side of the creek as the children. With the train in this “S” formation, three of Frank Scibelli’s playmates boarded one of the empty flat cars. Seeing this, Frank suddenly ran toward the train. Nellie Croesus shouted to him several times to keep away from the train. Frank testified that he heard someone calling “Come back, don’t go near the train”, but nevertheless, paying no heed to the warning, he attempted to board it. While he had his two hands on the ladder of one of the cars and his left foot on one of the rungs, the train jerked as a result of which Frank’s left leg slipped under the wheel and was severely crushed, requiring amputation below the knee.
The theory upon which the plaintiffs principally relied to establish negligence was the so-called playground doctrine. The basis of liability in cases coming within that doctrine is that where an owner permits children to use his premises as a playground, a duty arises to exercise ordinary care in keeping the premises safe. In Fitzpatrick v. Penfield, 267 Pa. 564, 572, 109 A. 653, Mr. Justice Kephaut said: “. . . When so used, ordinary care must be exercised to keep the premises in safe condition. Of course, this does not mean occasional or intermittent occupancy of another’s ground by children as a playground — or almost every foot of open or fenced land, would be under the exception to the general rule, and the general rule would then be the exception. The amount of use that will bring otherwise private ground within the playground rule must depend to a large extent on the circumstances of each case. It may be said that the use contemplated is such as to cause the place to be generally known in the immediate vicinity as a recreation center, and its occupancy should be shown to be of such frequency as to *286impress it with the obligation of ordinary care on the part of the owner.” See also Rahe et al. v. Fidelity-Philadelphia Trust Company et al., 318 Pa. 376, 178 A. 467; Gourley et ux. v. Pittsburgh, 353 Pa. 112, 116, 44 A. 2d 270.
The playing of various games by children on the land adjoining the defendant’s right-of-way was of sufficient frequency to bring it within the accepted definition of a playground. There was also some testimony, when viewed in a light most favorable to the plaintiffs, tending to establish that the tracks themselves formed a part of the playground. Mrs. Lillian Manz, who had lived for 18 years in a dwelling house overlooking The Willows, said that the children would see who could walk the rail the longest without falling off. William W. Uhrich, the janitor of a building overlooking the playground, testified that during the wintertime the children would take cinders and cover them with snow and slide over the tracks. Nellie Croesus, a participant in the alleged games, stated that the children did not exactly play on the tracks but used to run across them. Ealph Smith, who lived in the vicinity for three and a half years, testified that the children played around the railroad bridge and all along the railroad and to the east of the railroad.
However, even if the evidence be regarded as sufficient to show tacit assent by the defendant to the use of its tracks as part of the playground, the testimony will not support the claim that the defendant acquiesced in trespasses upon its trains. While there is some evidence that children had on occasions jumped on trains in the area of The Willows and had crossed over them when they were standing still for a period, the evidence was insufficient to establish this as a practice carried on with the knowledge and consent of the defendant. Considering the testimony most favorably to *287the plaintiffs in this respect, the boarding of trains was occasional only and there was no acquiescence in such conduct. On the contrary crew members made efforts to keep children from the trains. There was no testimony of a single instance when a child had been permitted to board or “take a ride” on a train passing through the area. A witness for plaintiffs testified that he had seen crew members chase boys off the train “quite often”, and from this counsel would have the inference drawn that there was an habitual practice of climbing or jumping on the trains. There was no amplification of this vague expression. Other witnesses testified that “sometimes” boys would attempt to board the trains. None of the witnesses could approximate the number or fix the times of such occurrences. The evidence was entirely too indefinite to establish the extent of such alleged practice or to supply the frequency and regularity required to bring it within the playground rule. Cf. Prokop et ux. v. Becker et al., 345 Pa. 607, 29 A. 2d 23; Riebel et al. v. Land Title Banh & Trust Co., 143 Pa. Superior Ct. 136, 17 A. 2d 742.
Thus while the testimony may have made the defendant chargeable with acquiescence in the use of the track as part of the children’s playground, this is not true of the trains which were operated on the track. A necessary element of the playground doctrine is permission or acquiescence in the use of the owner’s property. The presence of this element gives to the children the status of gratuitous licensees. The license, however, does not extend beyond the use to which the express or implied permission applies: See Prokop et ux. v. Becker et al., supra, at p. 609; Dumanski v. City of Erie, 348 Pa. 505, 507, 34 A. 2d 508; Eestatement, Torts, §341, comment b.
The case of Gawronski v. McAdoo, 266 Pa. 449, 109 A. 763, chiefly relied on by plaintiffs, is inapposite. *288There an eight-year old boy was injured while on the top of a freight car standing with other cars in a railroad yard containing an open area which had been used constantly for years as a playground without objection by the railroad company. Baseball had been played thereon for many years and defendant’s employes had frequently participated in the games. Freight cars which were left standing for some time were used by boys as grandstands to watch the ball games. For at least three-quarters of an hour before the accident the minor plaintiff and 14 other boys were seated on the freight car watching a ball game in full view of a number of defendant’s employes. Thus there was implied if not express permission to use the ears which customarily remained standing on the tracks for a considerable period of time. The injured boy had been in full view of the employes. Obviously the circumstances which were controlling in that case do not exist in the instant case where a train in normal operation was stopped only momentarily and the 'presence of the minor plaintiff on the train was unknown to defendant’s employes.
Counsel for the plaintiffs, however, insist that even if the train may not be considered a playground, the defendant owed a duty of care toward minor trespassers because it should have foreseen that children might attempt to board the train and taken measures to prevent such conduct. It is claimed that if one of the crewmen had been stationed toward the rear of the train, the accident could have been prevented.1
*289Needless to say, the operation of its trains by a railroad company over its right-of-way for the transportation of freight is an essential function. It is vital to commerce, and the public as well as the railroad company has an interest therein. The maintenance of service should not be made unduly burdensome. We have been referred to no case where a court has gone so far as to require a railroad company to patrol its tracks or police its trains with a sufficient number of guards to prevent children from attempting to board them. On the contrary, other jurisdictions have held that no such duty exists: See Smith v. Illinois Cent. R. Co., 214 Miss. 293, 313, 58 So. 2d 812, 819 (1952); Union Ry. Co. v. Williams, 6 Cir., 187 F. 2d 489, 493 (1951); Nolley v. Chicago, M., St. P. & P. R. Co., 8 Cir., 183 F. 2d 566, 569, 570 (1950); AngiUne v. Norfolk & W. Ry. Co. et al., 99 W. Va. 85, 128 S.E. 275, 277 (1925); Wilson v. Atchison, T. & S. F. Ry. Co., 66 Kan. 183, 186, 71 P. 282 (1903); The Oregon Ry. and Nav. Co. v. Egley, 2 Wash. 409, 26 P. 973 (1891). It is difficult to conceive how a proper operation of trains for the service of the public could be maintained if the standard of responsibility contended for received countenance.
In the present case the evidence adduced by the plaintiffs was conflicting as to which car of the train the minor plaintiff attempted to board and the plaintiffs’ testimony showed that the sporadic attempts to board a train occurred all along the railroad, both north and south of the railroad bridge which was in the middle of the area. Obviously a crewman stationed on *290the real* or any other car of the train could not adequately have prevented children from boarding the train at some other point, which might have been attempted from either side of the track. Especially was this true because of the winding course of the defendant’s right-of-way. But even if the track throughout the area had been straight, the orbit of duty sought to be imposed would have required the defendant to have an employe on practically every car of the train or watchmen stationed on both sides of the track throughout the area.
Under the facts of this case the impracticable and burdensome task of exercising police supervision over its trains would be out of proportion to the risk to minor trespassers involved.2 Determinative in this regard is our recent decision in the case of Shaw v. Pennsylvania Railroad Company, 374 Pa. 8, 96 A. 2d 923 (1953). There two of defendant’s freight trains had momentarily blocked a permissive crossing. The plaintiff, a boy of 12, undertook to climb over the cars. He had gone halfway across a flat car on the second track when the train started with a jerk and he was thrown under the wheels. He and other children and adults had climbed over the ears when they blocked the permissive path, and the plaintiff testified that this had been going on for a long time and that employes of the defendant knew about it. In affirming the entry of judgment n.o.v. for the defendant by the court below, we rejected plaintiff’s contention that the railroad company should have stationed guards at the permissive crossing. Certainly if there was no duty upon the railroad company to place guards to warn against the climbing over its cars at a permissive path across the tracks, there was no duty on the part of the defendant in the instant case to police its tracks throughout the area of The Willows.
*291We are obliged to hold that the unfortunate accident which occurred in the present case was not attributable to any negligence on the part of the defendant, but was proximately caused by the minor plaintiff’s own impulsive act.
Judgment affirmed.
It ia stated in appellants’ brief tbat on prior occasions when a train passed through the area a crewman was posted toward the rear of the train to warn or deter children from boarding it. The record does not support this assertion. The testimony showed that the trains operating on the spur line to and from the Bethlehem Steel plant consisted of a varying number of cars and would *289sometimes extend in length from Seventh Street to Eighth Street. One witness testified that on train runs he had observed a brakeman sometimes at the rear and sometimes on a car in the middle of the train. There was no testimony that such crewman was so stationed for any purpose other than the discharge of his duties in the operation of the train such as flagging at crossings, throwing switches, braking, etc.
Cf. Restatement, Torts, §339(d).