concurring:
I agree with Judge Barrett that we can consider whether the acquisition of the sleeping quarters at issue in this case by the St. Louis Southwestern Railway Com*831pany (SSW) was equivalent to the “construction” prohibited by the Hours of Service Act as amended, see 45 U.S.C. § 62(a)(4). I also agree with the result reached in his opinion. I write separately because my reasoning differs somewhat from his.
We stretch somewhat when wé say that the issue whether “acquisition” is equivalent to “construction” was properly preserved and argued on appeal. The issue was argued to the district court. It was set out clearly in the docketing statement, but we have stated that raising an issue in a docketing statement without subsequently arguing it in the briefs results in waiver. Bledsoe v. Garcia, 742 F.2d 1237, 1244 (10th Cir.1984); Whitehead v. Salyer, 346 F.2d 207, 209 n. 2 (10th Cir.1965). The issue was not argued orally in our court and is presented in the briefs only through a most generous reading. But we have made exceptions to the rule of waiver when the issue involved is of substantial public interest. See Platis v. United States, 409 F.2d 1009, 1012 (10th Cir.1969); see also Consumers Union of United States, Inc. v. Federal Power Commission, 510 F.2d 656, 662 & n. 9, 10 (D.C.Cir.1974) (citing Platis for exception due to substantial public interest). The argument was pursued better here than in Platis, and I agree with Judge Barrett that a substantial public interest is at stake in this issue of first impression.
In addition, although the district court found for the agency on its motion for summary judgment, we are not prevented from deciding the issue in favor of the union without remanding for trial. The parties stipulated to the only legally significant fact, i.e., the acquisition. The question whether that acquisition amounts to “construction” under the statute is one of law, which we can dispose of on appeal.
Although Judge Barrett’s opinion asks whether SSW’s “rehabilitation” of the sleeping quarters was equivalent to construction, and refers to a “proposed reopening” of the sleeping quarters, his discussion makes clear that the truly dispositive question is whether SSW’s acquisition of the quarters — not the construction work on the building or its reopening for sleeping— was equivalent to construction. If SSW’s acquisition of the property in March 1980 was unprotected by the statute’s grandfather clause, SSW’s use of the property as a sleeping quarters from that point until May 1980 violated the statute and regulation.
With the issue so clarified, I agree that the reference in 49 C.F.R. § 228.-101(c)(l)(iv) to “[acquisition and use of an existing building” should not be read to cover grandfathered facilities acquired by purchase from another railroad. To hold otherwise is inconsistent with the plain language of the regulation and the evidence we have of the congressional intention behind the statutory amendments.
I answer the Federal Railroad Administration’s (FRA) argument that we defer to its current interpretation by observing that there is nothing in the record to suggest that the agency had taken the position it now advocates before this litigation arose. Significantly, the agency said in its memorandum supporting its summary judgment motion that it had never interpreted “existing buildings” in § 228.101(c)(l)(iv) to mean grandfathered sleeping quarters; yet it fails to cite any prior agency statements or actions that take a contrary position. R. I, 89. And it admits that on its face “existing buildings” appears to refer to “any building in existence at the time of the acquisition.” Id. (emphasis added). We have deferred often and properly to agency interpretations of statutes or regulations. But this does not include simple acquiescence to their litigating positions. Rather judicial deference generally is reserved for agency views that have been reflected in formal pronouncements or have been known through other means for a long time. In Udall v. Tollman, 380 U.S. 1, 85 S.Ct. 792, 13 L.Ed.2d 616 (1965), for example, the agency interpretation at issue “had, long prior to respondents’ applications, been a matter of public record and discussion.” Id. at 17, 85 S.Ct. at 802. And in Hoover & Bracken Energies v. *832United States Department of Interior, 723 F.2d 1488 (10th Cir.1983), we upheld an agency interpretation consistent with its own ruling in a similar case ten years earlier. Id. at 1491-92.
Our responsibility goes beyond mere rubber stamping of ad hoc agency decision making or after-the-fact rationalizations. Although judges should refrain from “substituting their own interstitial lawmaking” for that of an agency so long as the agency's position is not irrational, we cannot abdicate our “ultimate judicial responsibility to determine the law.” See Ford Motor Co. v. Milhollin, 444 U.S. 555, 568, 100 S. Ct. 790, 798, 63 L.Ed.2d 22 (1980).
The agency made no contemporaneous statements on whether acquisition of grandfathered facilities from another railroad would be permissible. The proposed and interim regulations did not contain the acquisition language. Rather they referred only to creation of a new facility or expansion of an existing facility. Construction of Railroad Employee Sleeping Quarters; Interim Rules, 41 Fed.Reg. 53,-028, 53,030 (1976); Proposed Amendment to Hours of Service Regulations, 41 Fed. Reg. 53,070, 53,073 (1976). The final regulations, however, contained the acquisition language and some relevant commentary. In its discussion of the final rule, the FRA stated that the “acquisition of an existing structure for use as sleeping quarters is listed as an event clearly within the purview of the statute and these regulations.” Construction of Railroad Employee Sleeping Quarters; Final Rules, 43 Fed.Reg. 31,-006, 31,008 (1978) (emphasis added). It gave the acquisition of a commercial hotel or motel for the purpose of housing employees as an example of acquisition equivalent to “construction” under the statute and said it also would not permit railroads to rent such quarters owned by others, because the railroad’s ownership was not relevant to employee safety. Id.
None of the cited statements explicitly rules in or out a situation like the one before us, but in my view they are more supportive of Judge Barrett’s interpretation than Judge Anderson’s. The plain meaning of the regulation is nonrestrictive. I cannot accept Judge Anderson’s conclusion that the agency’s use of hotel acquisition as an example in its explanation of § 228.101(c)(l)(iv) meant that it intended to limit the regulation’s application to that context. Nor does the distinction make safety sense. As the agency reasoned in its discussion of temporary structures, potential hazards to employees housed in acquired dormitories are no less serious than those imposed on employees housed in acquired hotels. See 43 Fed.Reg. at 31,008.
The bottom line to me is the congressional concern for safety. The legislative history of the statutory amendments demonstrates that Congress’ main motive was safety, not economics. Committee reports from both houses reflect congressional frustration with the FRA’s earlier inaction on safety matters. See S.Rep. No. 855, 94th Cong., 2d Sess. 2-3, reprinted in 1976 U.S.Code Cong. & Ad.News 1534, 1535-36; H.R.Rep. No. 1166, 94th Cong., 2d Sess. 11. The railroads were alarmed at the potential cost — the loss of their existing investment in sleeping facilities. Congress apparently added the grandfather clause as an afterthought, to soften but not eliminate the blow of the stricter statutory requirements.1 The afterthought should not be allowed to defeat the aim of the legislation as a whole. I read Congress’ broader intention to mean that a railroad should make no significant additional investment in sleeping quarters near hazardous railroad switching or humping operations after July 1976. Judge Anderson’s dissent raises some interesting problems concerning applying the regulation to mergers, reorganizations, and the like. The case before us, however, presents not a post-Act reorganization or merger of two railroads, but rather an outright purchase of less than all of the assets of a failed railroad. I do not see why that acquisition should be treated dif*833ferently from the purchase of a hotel, which is prohibited. SSW was not committed to this investment before the legislation passed Congress. I do not think Congress intended the benefit SSW seeks here. Neither the wording of the statute nor the wording of the regulation requires such a result.
Therefore I concur with Judge Barrett’s reversal and remand.
. The FRA recognized this priority order in its comments to the interim tules. See 41 Fed.Reg. at 53,028 ("primary impetus" for statutory amendments was a rail yard accident).
. For convenience, references to the majority opinion include the concurring opinion, since the points in this dissent relate equally to both.