This is a proceeding by mandamus to compel appellant railways to comply with relator’s order that an interlocking plant be installed at the intersection of their lines at Aurora, Missouri.
The order referred to, in so far as material to the issues, reads as follows:
“Ordered: 1. That the St. Louis, Iron Mountain & Southern Railway Company and B. F. Bush, its receiver, and the St. Louis & San Francisco Railroad Company and James W. Lusk, Wm. C. Nixon and Wm. B. Biddle, its receivers, be and they are hereby ordered to construct, maintain and operate an interlocking plant at Aurora, Missouri, in accordance with the plans filed with the Commission within six months after the effective date of this order.
“Ordered: 2. That the actual work of construction, operation and maintenance be carried out by the St. Louis, Iron Mountain & Southern Railway and B. F. Bush, its receiver. '
*462“Ordered: 3. That the cost of construction, maintenance and*operation he divided as follows: St. Louis & San Francisco Railroad Company and its receivers, 75 per cent, and the St. Louis, Iron Mountain & Southern Railway Company and its receivers, 25 per cent.
“Ordered: 4. That the St. Louis & San Francisco Railroad’s portion of the cost of construction, maintenance and operation of said interlocking plant be paid in monthly installments to the St. Louis, Iron Mountain & Southern Railroad Company.
“Ordered: 5. That this order shall be in full force and effect on and after the 20th day of June, 1916, and that the Secretary of the Commission shall forthwith serve a duly certified copy of this order .and report on each of the parties hereto, and that the parties hereto notify the Commission within ten days after receipt of a copy of said order and report, whether the terms of the order are accepted and will be obeyed.”
Appellants are, respectively, the successors of • the defendants named in the order. For brevity, relator is hereinafter referred to as the Commission, and appellants as the Missouri Pacific and the “Frisco.” The predecessor of the Missouri Pacific accepted the order. The Frisco sued out a writ of certiorari in the Cole Circuit Court, which proceeding it subsequently dismissed. Thereafter, appellants took no steps looking to the carrying out of the Commission’s order, and that tribunal directed its counsel to institute this proceeding, which was done in April, 1918. Upon a hearing, the circuit court made the alternative writ mandatory, and both companies appealed.
On the hearings before the Commission and in this case in the circuit court the Frisco offered in evidence a contract, dated June 2, 1904, wherein the Iron Mountain, in consideration of a grant of “the right to construct, maintain and operate a single-track main-line railroad over and across” the Frisco right-of-way and railroad at Aurora, agreed, among other things, that whenever an interlocking plant ■ should be required at this crossing, either by tli'e Frisco or by law, the Iron *463Mountain would install sucia plant at its own cost and that the expenses of operation and maintenance should thereafter be borne by the two companies equally.
Appellant Frisco Company contends there is no basis in the evidence for a writ of mandamus against it; that the order of the Commission is invalid in that it unreasonably, arbitrarily and unlawfully ignores and violates the contract between appellants; that it impairs the 'obligation of that contract, takes and damages its property for public use without just compensation, takes its property without due process of law, abridges its privileges and immunities, and denies it the equal protection of the laws.
The Missouri Pacific, though appealing, aligns itself in support of the order of. the Commission and the judgment of the tidal court.
Mandamus. I. It is not contended the Commission lacks power to compel the installation of interlocking plants at proper places and on terms which |re just as betweeaa the companies affected. There seems to be no real opposition to the installation of such- plant at Aurora. The contention arises over the portion of the order apportioning* the expense. That question is not open for determination in this case. So far as concerns the Frisco Company the only duty attempted expressly to be imposed upon it by the order is simply one to pay iponthly a named proportion of the expenses of construction, operation and maintenance as they accrue. No duty to pay arises until the Missouri Pacific has proceeded with the work for at least one month.. There is nothing expressly required of the Frisco until that time has come. Assuming for present purposes that mandamus would lie to enforce a payment of money which had become due under this order, we do not think it can be held that the record justifies the judgment of the trial court. In order to warrant control by mandamus there must be an existing, clear, unconditional, legal right in relator and a corresponding present, imperative, unconditional duty *464upon the part of respondent, and a default by respondent therein. [State ex rel., v. Associated Press, 159 Mo. 410; State ex rel. v. Thomas, 245 Mo. 65; State ex rel. v. Stone, 269 Mo. 334:.] .Many other decisions cited in the briefs announce the same doctrine. The duty of the Frisco under the- Commission’s order is conditioned upon the doing* in the future of prescribed things by the Missouri Pacific. Nothing had been done' under the order when this proceeding was' instituted. The Frisco was not in default.
Respondent cites cases supporting the doctrine that: “All persons concerned in the separate but cooperative steps in the attainment of the result sought may be joined in one writ of mandamus. One writ of mandamus may issue against all the officers concerned in the separate but co-operative steps in the attainment of one result in the performance of a general duty.” The cases cited relate to the use of the writ against several public officials whose co-operative, though successive, action is essential to the end sought. This is not such a'case. The public is chiefly interested in the crossing protection. The division of expenses more particularly concerns appellants. When the plant is constructed and operated the purpose which constitutes the foundation of the right of the State to interfere is accomplished. This object is covered by the writ against the Missouri Pacific. It does not depend at all upon the payment of the sums which may become due from the Frisco to the Missouri Pacific.
Access to Right Way. II. It is suggested that the writ was necessary to give the Missouri Pacific access to the Frisco right-of-way for the purpose of'constructing the plant. There is no express mention of this in the order of the Commission. None was necessary. The order of the Commission became and is full authority for yie Missouri Pacific to proceed to perform its duties thereunder. Under that order, concededly authorized in so far as it directs the construction of the interlocking plant, the Frisco *465has no right or authority to deny the Missouri Pacific access to the crossing for the purpose of carrying out the order. The letters which are offered; to show a refusal of the Frisco to permit such access were written after this proceeding was begun, and are not, in our opinion, subject to that construction. In brief, they seem to have been designed merely to avoid any admission which might impair the right of the Frisco to continue to insist upon the termls of its contract; and the contract, also, gives the Missouri Pacific the right to enter.
Apportionment of cost. III. In the view we take of the case it is the duty of the Missouri Pacific to proceed with the construction of the plant. In the event the Frisco fails to pay the sums which may become due under the terms of the order of the Commission, the Missouri Pacific ^ }U\°ke Pr0Per meanS to Collect> if under the law and the facts collection is legally possible. The public is served when the plant is installed. The proper apportionment of expense is rather a matter between appellants. In that proceeding the other questions attempted to be raised in this case may be more relevant to the issues.
The judgment as to the Frisco is reversed; that as to the Missouri Pacific is affirmed.
Walker, C. J., and Williams and Williamson, JJ., concur; Goode, J. concurs in the result; Graves, J., concurs in separate opinion; Woodson, J., not sitting.