<ARTICLE>                     5
<LEGEND>
This schedule contains financial information extracted from SEC filing Form 10-K
and is qualified in its entirety by reference to such financial statements.
</LEGEND>
<MULTIPLIER>                                            1,000
       
                               
<PERIOD-TYPE>                  12-MOS
<FISCAL-YEAR-END>                                 DEC-31-1997
<PERIOD-START>                                    JAN-01-1997
<PERIOD-END>                                      DEC-31-1997
<CASH>                                                 $8,671
<SECURITIES>                                                0
<RECEIVABLES>                                          97,374
<ALLOWANCES>                                            2,162
<INVENTORY>                                             7,758
<CURRENT-ASSETS>                                      122,795
<PP&E>                                                571,422
<DEPRECIATION>                                        246,236
<TOTAL-ASSETS>                                        853,781
<CURRENT-LIABILITIES>                                       0
<BONDS>                                                     0
<PREFERRED-MANDATORY>                                       0
<PREFERRED>                                                 0
<COMMON>                                                    0
<OTHER-SE>                                                  0
<TOTAL-LIABILITY-AND-EQUITY>                                0
<SALES>                                               641,950
<TOTAL-REVENUES>                                      641,950
<CGS>                                                       0
<TOTAL-COSTS>                                         526,195
<OTHER-EXPENSES>                                      (9,203)
<LOSS-PROVISION>                                            0
<INTEREST-EXPENSE>                                      8,698
<INCOME-PRETAX>                                       116,260
<INCOME-TAX>                                           47,461
<INCOME-CONTINUING>                                    68,799
<DISCONTINUED>                                              0
<EXTRAORDINARY>                                             0
<CHANGES>                                                   0
<NET-INCOME>                                          $68,799
<EPS-PRIMARY>                                           $1.81
<EPS-DILUTED>                                           $1.80