<ARTICLE> 5 <MULTIPLIER> 1,000 <PERIOD-TYPE> 3-MOS <FISCAL-YEAR-END> DEC-31-1998 <PERIOD-START> JAN-01-1998 <PERIOD-END> MAR-31-1998 <CASH> 22,166 <SECURITIES> 0 <RECEIVABLES> 330,411 <ALLOWANCES> 10,290 <INVENTORY> 39,387 <CURRENT-ASSETS> 420,827 <PP&E> 1,877,563 <DEPRECIATION> 955,483 <TOTAL-ASSETS> 1,369,453 <CURRENT-LIABILITIES> 294,344 <BONDS> 248,993 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 50,682 <OTHER-SE> 654,736 <TOTAL-LIABILITY-AND-EQUITY> 1,369,453 <SALES> 0 <TOTAL-REVENUES> 750,193 <CGS> 0 <TOTAL-COSTS> 692,657 <OTHER-EXPENSES> 0 <LOSS-PROVISION> 0 <INTEREST-EXPENSE> 3,916 <INCOME-PRETAX> 53,620 <INCOME-TAX> 21,260 <INCOME-CONTINUING> 32,360 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 32,360 <EPS-PRIMARY> 0.65<F1> <EPS-DILUTED> 0.63<F2> <FN> <F1>EARNINGS PER SHARE - BASIC (IN COMPLIANCE WITH SFAS 128) <F2>EARNINGS PER SHARE - DILUTED (IN COMPLIANCE WITH SFAS 128) </FN>