Penn Central's wreck finally was cleared from the bankruptcy track yesterday, concluding a reorganization for the largest business failure in American history.

At a simple ceremony in Philadelphia sagas of the once-proud Pennsylvania Railroad and New York Central ended. The two roads had joined in 1968 for an ill-fated merger that collapsed on June 21, 1970.

Yesterday, three court-appointed trustees turned over what is left of the former Penn Central Transportation Co. to a 12-man board of directors for an entirely new enterprise.

And there is much irony in what is left. Although most railroad assets of the former Penn Central Transportation Co. have been taken over for a government-directed rail reorganization, the new business retains diverse real estate oil pipeline and amusement park holdings that make it one of the nation's largest companies.

The federal Treasury, meanwhile, is underwriting losses of the company's former main rail lines, which are important transportation links throughout the Midwest and Northeast.

Penn Central Corp. is the name under which the reorganized firm began business yesterday 8 years, 4 months and 3 days after its predecessorfailed. With assets that have been estimated at some $4 billion, the new company would rank among the 50 largest industrial firms in the country.

Named to head the company was Richard Dicker as chairman and chief executive. He nows well the problems suffered by the bankrupt railroad firm because he represented a major investor in the old Penn Central.

The 60-year-old executive was vice president and deputy general counsel of Equitable Life Assurance Society, which had invested more than $26 million in the railroad and owned more bonds than any other creditor.

He will oversee initial operations of a company with some 16,500 employes at subsidaries that include the Six Flags amusement parks, part of the Great Southwest real estate development firm with projects in California, Florida, Georgia, Missouri, New Jersey and Texas.

Penn Central Corp. also owns Buckeye Pipeline Co., a 4,427-mile system in the Northeast and Midwest; Edgington Oil Co., a California refinery and petroleum distributor; Arvida Corp., builder of residential communities in Florida and Georgia; and some 5,000 miles of unused rail lines as well as the profitable Pittsburgh & Lake Erie Railroad, which it wants to sell.

At an initial meeting of the new firm's board yesterday, Frank E. Loy was elected president and chief operating officer. Loy has headed Pennsylvania Co., of Arlington, a Penn Central subsidiary that controlled most non-rail assets.

It was a day of many developments associated with the beginning for any new venture although the transition had been prepared over many months and approved by creditors of the former bankrupt firm, which dated back to 1842. Among actions taken:

All trading on the New York Stock Exchange of the old Penn Central ended, with a final quote of $1.62 apiece - to be swapped for new common at the rate of one new share for each 25 owned.

Officers said they started to distribute to former creditors and claimants $1.4 billion of debt securities, 28 million shares of preference stock, 23 million shares of common and $220 million in certificates. It may be a decade before all $3.5 billion in claims are settled finally.

The company said it will remain based in Philadelphia, for the time being.

A report is being prepared for filing with the Securities and Exchange Commission, detailing the business, capitalization, management and financial structure.

Still unsettled is litigation involving the amount of money the new firm may recover from the U.S. government for properties transferred to the new Northeast rail firm, Consolidated Rail Corp.