The rulings and directions of the court upon the trial were in all particulars correct.
*203It was made the duty of the plaintiffs, by special statutes enacted for that purpose, to do the work and perform the service for which compensation is sought to be recovered in this action. Sts. 1856, c. 296 ; 1857, c. 128. The work was executed under the supervision of a commissioner, the validity of whose appointment and authority cannot in this suit be contested. Fitchburg Railroad v. Grand Junction Railroad and Depot Co. 1 Allen, 552. And the change in the grade and track of the highways, town ways and passage ways necessary to its accomplishment, was made with the consent of the county commissioners of the county of Middlesex. After the completion of all the work required of them, the cost incurred by the plaintiffs in its execution was duly apportioned between the two corporations by the commissioner, and a demand of payment was made upon the defendants for the sums to which the plaintiffs were entitled, according to the terms of his apportionment. Payment having been refused, the plaintiffs became entitled by the express provisions of the statutes to recover, in an action at law, a fair and just proportionate part of the cost incurred in lowering the track and road beds, in furnishing materials for and in constructing the railroad bridge and its appendages, and in constructing a connecting track between the roads of the Fitchburg and the Boston and Lowell Railroads.
It is no valid objection to the right of the plaintiffs to maintain this action, that they did not ask or petition for the consent of the county commissioners to make changes in the grade and construction of the roads of the two corporations, or that such consent was given without its having been asked for. The plaintiffs were expressly authorized and required to lower the surface of the two railroads to one and the same common level, and, upon a true construction of the statute, the consent of the county commissioners was essential only in reference to the public and private passage ways which would be affected by the alteration in the grade and level of the railroads.
Nor can the plaintiffs be deprived of their right to recover a just and fair proportionate part of the expenses incurred by them in the execution of a work, the performance of which was *204expressly imposed upon them by lawful authority, either by the consideration that the acts in question were enacted upon their petition, or that in the supervision of the work and in making an apportionment of the expenses incurred, the commissioner conducted himself, if it were so, with partiality towards them. As to the one, it is sufficient that the statute was duly enacted, and that the authority was given and the duty imposed. And if the commissioner, acting in his official capacity under his appointment by the governor, was guilty of any delinquency or violation of his duty, he is amenable to the public authority for his misconduct; and his ultimate decision in the apportionment of the cost of the work between the two parties could not be the occasion of any injury or disadvantage to the defendants, since it was not conclusive or binding upon them, but on the contrary they had the privilege, from which the plaintiffs were excluded, of electing whether to abide by his award, or to submit to a jury to determine what was the fair and just proportion of the expenses incurred which they should be required to pay.
The proper rule in relation to the amount which the plaintiffs were entitled to recover was laid down in the instructions to the jury upon that subject. This rule is prescribed in clear and distinct terms in the language of the statute. It is, that they shall recover a fair and just proportionate part of the cost incurred. And this by necessary implication excludes from the estimate of the compensation to be recovered all considerations respecting the effect of the alteration upon the value of the defendants’ property in their franchise, or as to the expense of the future maintenance of their road, or the increased difficulty of transacting their business upon it. These are considerations upon which an appeal might well have been made to, and which it must be presumed were all duly regarded by, the legislature, in the establishment of the rule, which can now be the only standard by which the rights of the parties are to be determined.
All the evidence, therefore, which was offered by the defendants upon these subjects was rightly excluded by the court. The instructions to the jury were cautiously and guardedly -stated, making it essential to their right of recovery that the *205plaintiffs should prove every fact which the statute prescribes as a condition precedent to the maintenance of an action, and limiting the amount for which a verdict should be rendered to the just share of the expenses incurred which the defendants ought to pay, without any regard to the apportionment of the commissioner, or considering it as evidence upon the question to be determined.
To the more general objection that the statutes under which the plaintiffs proceeded to execute the work and perform the duties assigned to them are unconstitutional and void, as being violations of a contract, or as a taking of property for private use, or for public use without due compensation, there is a direct and decisive answer. The charters of all the railroad companies which were to be affected by these acts were subject to alteration, amendment or repeal at the pleasure of the legislature, under the several provisions of the law concerning corporations. Rev. Sts. c. 44, § 23. Under this broad reservation, it was within its power completely to determine in what manner the franchise granted, in the exercise of the right of eminent domain, for important public purposes, should be enjoyed and exercised. And having first rightly ordered that certain specific changes, required by public safety and convenience, should be made in the level, grade and surface of the road beds, and in their crossings and connections with each other, it is but a necessary consequence of the exercise of this authority that the legislature should prescribe by whom, in what manner and under whose supervision the work should be accomplished, and in what proportion, according to their respective interests, it should be paid for by the parties affected by it.
And as to the connecting track between the Fitchburg and the Boston and Lowell Railroads, which the plaintiffs were required to construct, and to which the defendants particularly apply this objection, upon the ground that it was not constructed at their request or upon them application, the answer is, that the connecting track became, upon the completion of the other alterations, essential to the defendants to give and preserve to them a continuity in the line of their own road, without *206which it would be impossible to run cars or transport passengers or merchandise from one end to the other upon it. And as it was their duty to keep up and maintain their whole road so that it could be thus used and enjoyed by the public, they might, in pursuance of alterations to which under their charter they were subject, be required to make the whole of such connecting track at their own expense; and therefore when it is ordered and made for the common benefit of them and of other parties, it is reasonable and lawful that they should be required to contribute a fair and just proportion of its cost; and this is all to which they are made liable by the statute. No contract is violated; no property is taken from them for private use, and none for the public without compensation ; but they are simply required to pay their just portion of the cost of structures essential to the enjoyment of their franchise, and which by law they are bound to maintain. Exceptions overruled.
Hoar, J. did not sit in this case.