delivered the opinion of the Court:
The chief error assigned consists in the refusal of the court, at the conclusion of tho taking of the testimony, to grant the request of defendants for an instructed verdict, “on the ground that the condition complained of in the declaration was part of a. plan or design adopted by the railroad company with the approval of the District of Columbia; and that the municipality was not liable for injury due to inadequacy of a plan or device.” ^Exception was reserved by each of the defendants.
By reference to the acts of Congress affecting the construction of the street railway in question, we find in see. 2 of the Act of February 18, 1875 (18 Stat. at L. 328, chap. 82), which is the charter of the Anacostia & Potomac River Railroad, the branch of defendant’s line upon which this accident happened, it is provided “that in the manner of laying its tracks, and paving the same, this company shall be under the control of the executive authority of the District of Columbia; and it shall pave its tracks, and the spaces between them, and for the space of 2 feet beyond the outer line thereof, and keep the same in good order, without expense to the United States or the District of Columbia ;„ and that said pavement shall be as prescribed by the said executive authority of the District of Columbia.”
The Act of Congress approved March 3, 1905 (33 Stat. at L. 981, chap. 1412), extending the Anacostia line of Nichols arc-*101imp, provides in sec. 3 “that all plans of location and construction shall be subjected to the approval of the commissioners of the District of Columbia;” and in sec. 5, “that the said railway and its appurtenances shall be constructed in a substantial and durable manner, subject to inspection by the commissioners of the District of Columbia;” and in sec. 7, “that the company shall keep the space between its rails and tracks and 2 feet exterior thereto in good condition, to the satisfaction of the commissioners of the District of Columbia.” t
, We think, in the light of the allegations of negligence and of the testimony, the defendant railway company must be relieved from liability. It was required to construct its track under the supervision of the executive authority of the District of Columbia. The engineer of the railway company who had charge of the construction of the railway testified “that the construction work was done in the fall and winter of 1911, with the permission and under the supervision of the District of Columbia; that the District of Columbia wras represented by an assistant engineer during this period of construction; that in the construction of the tracks there were inserted between the rails what are known as breakers or headers, which are placed on heavy grades to prevent the washing of the surface matter or gravel from the track. That they wrere placed about 50 feet apart; that they were made of a lighter section than the track rail; that they were placed crosswise in the tracks, embedded in the ground, laid on top and fastened to the railroad ties at right angles to the rails; that these headers were almost the width of the track, but not the entire width, because it was necessary to leave room for the wheels of the cars to pass along the track; that the space varied approximately from 3 to Sjdj inches; * * * that this plan of construction at the end of the header, between the rail and the end of the header, did not contemplate the filling in of the space by sand or dirt; that there was enough space for the wheel to freely operate upon the track; that the flange on the inner side of the wheel comes on the inside of the rail; that the space between the end of the header and the rail was obvious to a person using the track.”
The assistant engineer of the District testified that he “had *102been assistant engineer acting as assistant superintendent of suburban roads for about five or six years; that ho bad charge of the roads in the District outside of the city limits in connection with the maintenance of the surface and the drainage conditions.” After describing the construction on Nichols avenue and his familiarity with the conditions there, he stated “that the designing was usually left to the railroad company; that when a plan' of railroad construction was proposed, his work on behalf of the District of Columbia came into play in determining the desirability of that plan to accomplish the purpose for which it was designed; that he had a professional knowledge of the propriety, desirability, efficiency, and effectiveness of the device at the point in question on Nichols avenue; * * * that the device which was installed between the tracks of the Washington Railway & Electric Company at that time, for the purpose of preventing the washing of the surface, was good engineering.” It is true that this witness, expressing his opinion as to the size of the space left between the end of the header and the rail, said: “I would not like it as well as I would the narrower space, because it gives a larger wheel a chance to get in there, and it will wash out quicker. As a rule, that space is filled with stones all the while, and the flange of the wheel makes its own impression there as to the width of it.” He also stated that he would regard it as good engineering to keep these spaces filled.
But whether the spaces in some instances were kept open or were allowed to become filled is unimportant, since it appears that the open space was the approved plan, and the style of construction adopted and approved, and that- was the exact condition of the space when the accident occurred. It further does not appear that the assistant engineer of the District here testifying was the one who supervised the construction of the railway. There is no evidence that the District, subsequent to the construction of the tracks, notified the railway company to change the plan originally adopted and to thereafter keep the spaces filled. It clearly appears that the cause of the accident, as laid in the declaration and proved, was due to a condition in the tracks growing out of the plan of construction originally *103adopted by the railway company and supervised and approved by the District.
The nonliability of the railway company does not consist in the fact that the tracks may have been laid in accordance with a general plan submitted by it to conform to conditions similar to those existing on Nichols avenue, but in the fact that the plan there decided upon was used with the approval of the District. The courts are practically unanimous in holding that when a railway company constructs its railroad as directed by the municipal authorities when acting within the powers conferred upon them, no negligence can be imputed to it. Thomp. Neg. 2d ed. sec. 1364; Campbell v. Frankford & S. C. R. Co. 139 Pa. 522, 21 Atl. 92; Seibert v. Missouri P. R. Co. 188 Mo. 657, 70 L.R.A. 72, 87 S. W. 995; Morie v. St. Louis Transit Co. 116 Mo. App. 12, 91 S. W. 962.
It must, however, be clearly understood that we by no means commit ourselves to a rule that a street railway company may place an obstruction in the street notoriously dangerous, with knowledge of the existence of comparatively safe appliances which it could have originally installed or substituted for the dangerous device, and then take refuge behind municipal approval. But, as here, where no attempt has been made to show a safer plan of construction in common or known use, and nothing more is shown than that on one or two previous occasions wheels had caught in the spaces in question, a common occurrence in driving vehicles over and about railway tracks, we think it wmuld be equivalent to totally ignoring the general rule of nonliability in this class of cases to hold that, under the declaration and the proof before us, a case has been made out against the railway company, which should have been submitted to the jury. The sharp distinction involved in the above exception should be clearly alleged and supported by proof to justify the submission of the question to the consideration of a jury.
In Morie v. St. Louis Transit Co. supra, where, as here, plaintiff was injured by being thrown from a vehicle, caused by a wheel catching in a switch plate, the distinction is clearly pointed out, as follows: “Kailway tracks are a source of some *104danger to such persons; for it is not uncommon for the wheels of a vehicle to be wrenched off in driving diagonally over tracks, and occasionally someone is thrown to the ground in that way and hurt. Such occurrences happen with comparative frequency in driving over the intersections of ordinary switches or of sidewalks with main lines. Freight wagons often get caught in street car tracks. Those instances must be borne with, for the sake of the public service rendered by the railways. As we have stated, the lawfulness of the obstruction depends on the necessity for maintaining it, its utility, and the degree of inconvenience and danger it entails. And this is recognized in the decisions on the subject, despite the broad propositions often declared. Of course, the need to maintain an appliance is to be considered. Its danger may be so great that no necessity will justify its use. Comparisons must be instituted. A given implement may be somewhat dangerous, but not too much so to be used, if there is nothing safer; when, if a safer one can be obtained, it would be remiss to use the other. But this latter consideration would come up only in a case for negligence in choosing an inferior appliance. The present case does not require us to commit this court to. any extreme doctrine regarding what structures in a street are permissible. Without doing so, we need not hesitate to declare that no evidence was adduced tending to show the switch in question was either unnecessary, or obstructed or endangered travel to an extent which rendered its presence in the street a nuisance, .as alleged' and thereby made defendant answerable, as a tort-feasor, to plaintiff.”
We come now to the more difficult question of the liability of the District of Columbia. We are here called upon to distinguish between those powers of municipal corporations which are discretionary or judicial in character and those powers which are purely ministerial. We are not concerned in this case with those powers of municipal corporations which embrace governmental duties delegated to the municipality by the legislature, and in which the municipality acts as the agent of the State. In selecting and adopting a general plan of public improvement, such, for example, as a sewer system, the municipal corporation exercises judicial discretion, but in carrying out the plan it *105acts ministerially, and must perforin the work in a reasonably safe and skilful manner. Acting in good faith, it, therefore, would not be liable for an error of judgment in constructing such a system.
This distinction finds expression in the case of Johnston v. District of Columbia, 118 U. S. 19, 30 L. ed. 75, 6 Sup. Ct. Rep. 923, as follows: “The duties of municipal authorities, in adopting a general plan of drainage, and determining when and where sewers shall be built, of what size and of what level, are of a quasi judicial nature, involving the exercise of deliberate judgment and large discretion, and depending upon considerations affecting the public health and general convenience throughout an extensive territory; and the exercise of such judgment and discretion, in the selection and adoption of the general plan or system of drainage, is not subject to revision by a court or jury in a private action for not sufficiently draining a particular lot of land. But the construction and repair of sewers, according to the general plan so adopted, are simply ministerial duties; and for any negligence in so constructing a sewer, or keeping it in repair, the municipality which has constructed and owns the sewer may be sued by a person whose property is thereby injured.”
The plan here was formulated and adopted by the railway company, and it was approved, and the construction supervised and directed, by the District, acting, under the direction of Congress, through its assistant engineer. The duty was not imposed upon the District of formally preparing and adopting any general plan, but of approving and supervising the construction under the plan prepared and presented by the railway company. But the relation of the District to the present controversy is the same, whether the tracks were constructed by the railway company upon a general plan furnished by the District, or upon its own plan approved and supervised by the District. Hayden v. Fair Haven & W. R. Co. 76 Conn. 355, 56 Atl. 613; McKillop v. Duluth Street R. Co. 53 Minn. 532, 55 N. W. 739; Miller v. Lebanon & A. Street R. Co. 186 Pa. 190, 40 Atl. 413. In the McKillop Case,; the court announced the general rule in cases involving municipal supervision as follows: “A municipal *106corporation lias, through its council, control and charge of the streets, and may regulate the Dying of street railway tracks upon them; and if the council directs the railway company to lay the tracks upon a specified level or grade, and so Dying them makes the street unsafe for ordinary travel, the municipal corporation would doubtless be liable for injuries resulting therefrom. But it could hardly be said that so laying them would be an act of negligence on the part of the railway company.”
We think the liability of the District here must be treated as arising primarily from the paramount duty imposed upon it of maintaining the streets in reasonably safe condition. The liability of the District in damages for accidents due to failure to maintain the streets in reasonably safe condition is settled. In District of Columbia v. Sullivan, 11 App. D. C. 533, 541, the court said: “And it is held by express and repeated decisions of the Supreme Court of the United States, that the municipal corporation of this District is liable for injuries to persons arising from the negligence of its officers and agents in constructing and maintaining in safe condition, for the use of the public, the streets, avenues, alleys, public roads, and bridges, and all public sidewalks of the city of Washington and of the District of Columbia. Barnes v. District of Columbia, 91 U. S. 540, 23 L. ed. 440; District of Columbia v. Woodbury, 136 U. S. 450, 34 L. ed. 472, 10 Sup. Ct. Rep. 990.”
But, adopting the reasoning of the District, as we must, that the approval of the plan presented by the railway company was equivalent to its ad ption by the District, to what conclusion does it logically lead ? Having adopted a plan and created an existing condition on the street in pursuance thereof, if it subsequently appears that the condition thus created renders the street unsafe, the District must go further and perform the duty cast upon it, growing out of its general supervision of the streets, to exercise ordinary care and take the necessary additional steps to make the street, thus encumbered with the product of its plan, reasonably safe for travel. Loewer v. Sedalia, 77 Mo. 431; Chicago v. Gallagher, 44 Ill. 295.
We think the duty imposed upon the District to keep the *107streets in reasonably safe condition is controlling, whether a dangerous condition is the result of a general plan of improvement, or not. The action is not for negligence because of a defective plan, but for maintaining the streets in an unsafe condition. For example, a general plan for a sewer system may be adopted; but, in its construction, let us assume that the tops of the manholes in the street are sunk a foot below the surface of the pavement, creating a hole or depression, and as a result thereof a person sustains injury. The action would not be based upon a defective plan, or, technically speaking, upon the defective construction of the sewer, but upon the negligence of the municipal authorities in permitting a dangerous condition to exist in the street, as the result of defective construction. So, here, the question is whether the plan of construction followed, which wholly affected the condition of the surface of the street, coincided with the plan approved, and tended to make the street reasonably safe for travel. If so, the plan must be held to be a reasonable one, and the city would not be liable for injury occurring as a result of its adoption and installation. But if it left the street in a dangerous and unsafe condition, it could not be held to be a reasonable plan, when measured in the light of the paramount duty imposed of keeping the streets at all times in a reasonably safe condition.
Considering' a similar situation in the case of Finney v. District of Columbia, 41 App. D. C. 48, where the plaintiff was suing for injuries sustained from stepping into a tree space in the sidewalk, the court said: “If it [the condition complained of] wras dangerous it could not be held to conform to any reasonable plan of construction, irrespective of the condition of spaces in other parts of the city. If constructed according to plan, or otherwise, the District could not avoid liability if it was allowed to become dangerous. If the plan adopted was a reasonable one, and the space in question conformed to that plan, the District would not be liable; but if the plan was not reasonable, or through neglect the space had become dangerous, then the duty of the District would be the same as that imposed upon it with respect to any condition of the street or sidewalk which is permitted to become a menace to the safety of persons traveling *108thereon. A municipal corporation is liable for personal injuries caused by defects in a lawful obstruction in a street caused by want of proper supervision. District of Columbia v. Duryee, 29 App. D. C. 327, 10 Ann. Cas. 675.”
The whole question of the liability of the District was one for the jury. While the real question here involved was to somq extent touched upon in the instructions of the court below, the instructions were given, and the case tried, upon the theory of the joint liability of the railway company and the District, and we think was not so clearly presented upon the question of the separate liability of the District as to obviate possible confusion in the minds of the jury. We think, for this reason, that there should be a new trial.
The judgment is reversed, with costs, and the cause remanded for a new trial. Reversed and remanded.