The U.S. tax code, one of the few works guaranteed to fascinate and anesthetize, has acquired an important role in the Transportation Department's plans to sell Conrail to the Norfolk Southern Corp.

The question is whether the $1.2 billion in cash Norfolk Southern has offered to pay the federal government for the northeastern freight railroad is really a bargain-basement price because of the tax benefits Norfolk Southern would derive from the purchase.

Those in favor of the sale -- including Norfolk Southern and the Transportation and Treasury departments -- see those benefits as nothing more than what the tax code would make available to any purchaser.

Some of those opposed -- including Conrail's management, some members of Congress and Rolling Stone national editor William Greider, who wrote a piece on the subject entitled, "How to Steal a Railroad" -- find the tax situation outrageous.

The bottom line appears impossible to calculate, at least at this point. There are as many opinions as there are tax lawyers on how much Norfolk Southern could realize, and how soon.

L. Stanley Crane, Conrail's chairman and a man who favors the sale of Conrail's stock to the public, not Norfolk Southern, told a Senate hearing that, "Thanks to those financial benefits and tax breaks, it is conceivable that when all is said and done, a Norfolk Southern takeover of Conrail will have a net cash benefit to Norfolk Southern, perhaps in as little as five years, of hundreds of millions of dollars more than the $1.2 billion Norfolk Southern will pay for Conrail. Is that in the best interests of the taxpayers?"

The administration, on the other hand, has decided its proposed solution is appropriate. Ronald A. Pearlman, assistant treasury secretary for tax policy, told the Senate that, in his judgment, the negotiated agreement between the United States and Norfolk Southern provides "a very fair tax arrangement."

Pearlman said in an interview that, "The only sensible way I found to analyze this was to say, 'What would have happened had Conrail been sold by a private party? Is Norfolk Southern getting something in this deal it would not have gotten had it purchased from a private party?' The answer is no."

Pearlman added that, "if we want to criticize tax rules . . . that is a much broader issue than Conrail."

Norfolk Southern's purchase price is $1.2 billion for the federal government's 85 percent share of Conrail's stock, and $375 million for the 15 percent held by an employes stock ownership plan. Norfolk Southern agrees to surrender Conrail tax benefits called net operating loss carry-forwards and investment tax credits that total $2.4 billion.

Conrail has cash on hand of about $800 million, but Norfolk Southern has agreed to keep $500 million in reserve for five years. The other $300 million can be spent only on Conrail, according to Federal Railroad Administrator John H. Riley.

Norfolk Southern also would acquire Conrail's assets -- locomotives, rolling stock, track and real estate -- valued at $3 billion. Norfolk Southern-Conrail would be able over the years to claim tax benefits for the depreciation of that property. Those assets were there before the taxpayers created Conrail from the Penn Central and six other railroads, and therefore should remain with Conrail as they would with any property, administration officials say.

Conrail has used 10-year, straight-line depreciation rather than accelerated depreciation that would permit a much larger deduction in a given year. Norfolk Southern could not change that depreciation policy without seeking a difficult-to-get Internal Revenue Service tax ruling, all sources interviewed agreed.

Congress' Joint Committee on Taxation, in a seven-page letter to Sen. Howard M. Metzenbaum (D-Ohio), identified "four broad areas of concern" about the sale, but said, "The tax consequences . . . cannot be determined in the absence of details." The committee staff is continuing its study of the transaction and has reached no conclusions.

Metzenbaum issued a press release, however, that said, "If the analysis is correct, the sale could be one of the biggest tax shelters in history and one that is guaranteed by the federal government."

Conrail is obligated to file federal tax returns and is liable to pay taxes, but has never had to because of its early-year losses. It made $500.2 million last year.