<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
STATEMENT OF INCOME FOR THE THREE MONTHS ENDED MARCH 31, 1998 AND THE BALANCE
SHEET AT MARCH 31, 1998 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               MAR-31-1998
<CASH>                                           7,975
<SECURITIES>                                         0
<RECEIVABLES>                                  135,366
<ALLOWANCES>                                     8,827
<INVENTORY>                                      1,413
<CURRENT-ASSETS>                               164,126
<PP&E>                                       1,678,550
<DEPRECIATION>                                 878,996
<TOTAL-ASSETS>                                 979,143
<CURRENT-LIABILITIES>                          225,679
<BONDS>                                        227,784
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                       191,968
<OTHER-SE>                                     143,895
<TOTAL-LIABILITY-AND-EQUITY>                   979,143
<SALES>                                              0
<TOTAL-REVENUES>                               155,755
<CGS>                                                0
<TOTAL-COSTS>                                  116,388
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               4,479
<INCOME-PRETAX>                                 35,212
<INCOME-TAX>                                    14,413
<INCOME-CONTINUING>                             20,799
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    20,799
<EPS-PRIMARY>                                        0
<EPS-DILUTED>                                        0