<ARTICLE> 5
<LEGEND>
This schedule contains summary financial information extracted from the
June 30, 1999 quarterly consolidated financial statements and is
qualified in its entirety by reference to such financial statements.
</LEGEND>
<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-START>                             JAN-01-1999
<PERIOD-END>                               JUN-30-1999
<CASH>                                           6,251
<SECURITIES>                                         0
<RECEIVABLES>                                  122,497
<ALLOWANCES>                                     2,385
<INVENTORY>                                      4,796
<CURRENT-ASSETS>                               169,558
<PP&E>                                         818,756
<DEPRECIATION>                                 295,049
<TOTAL-ASSETS>                                 695,394
<CURRENT-LIABILITIES>                          124,562
<BONDS>                                        222,060
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           319
<OTHER-SE>                                     278,034
<TOTAL-LIABILITY-AND-EQUITY>                   695,394
<SALES>                                              0
<TOTAL-REVENUES>                               556,577
<CGS>                                                0
<TOTAL-COSTS>                                  516,978
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0<F1>
<INTEREST-EXPENSE>                               7,488
<INCOME-PRETAX>                                 33,440
<INCOME-TAX>                                    13,543
<INCOME-CONTINUING>                             19,897
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    19,897
<EPS-BASIC>                                        .63
<EPS-DILUTED>                                      .61
<FN>
<F1>Provision for Doubtful accounts included in costs and expenses applicable
to revenues.
</FN>