SECURITIES AND EXCHANGE COMMISSION
   WASHINGTON, D.C.  20549

   SCHEDULE 14D-1
   AMENDMENT NO. 12
   TENDER OFFER STATEMENT PURSUANT TO SECTION 14(D)(1) OF THE SECURITIES
   EXCHANGE ACT OF 1934

   SANTA FE PACIFIC CORPORATION
   (NAME OF SUBJECT COMPANY)

   UNION PACIFIC CORPORATION
   UP ACQUISITION CORPORATION
   (BIDDERS)

   COMMON STOCK, PAR VALUE $1.00 PER SHARE

   (TITLE OF CLASS OF SECURITIES)

   802183 1 03
   (CUSIP NUMBER OF CLASS OF SECURITIES)

   RICHARD J. RESSLER
   ASSISTANT GENERAL COUNSEL
   UNION PACIFIC CORPORATION
   EIGHTH AND EATON AVENUES
   BETHLEHEM, PENNSYLVANIA  18018
   (610) 861-3200
   (NAME, ADDRESS AND TELEPHONE NUMBER OF PERSON AUTHORIZED TO
   RECEIVE NOTICES AND COMMUNICATIONS ON BEHALF OF BIDDERS)

   with a copy to:

   PAUL T. SCHNELL, ESQ.
   SKADDEN, ARPS, SLATE, MEAGHER & FLOM
   919 THIRD AVENUE
   NEW YORK, NEW YORK  10022
   TELEPHONE:  (212) 735-3000

          Union Pacific Corporation, a Utah corporation ("Parent"),
     and UP Acquisition Corporation, a wholly owned subsidiary of
     Parent (the "Purchaser"), hereby amend and supplement their
     Statement on Schedule 14D-1 ("Schedule 14D-1"), filed with the
     Securities and Exchange Commission (the "Commission") on November
     9, 1994, as amended by Amendment No. 1, dated November 10, 1994,
     Amendment No. 2, dated November 14, 1994,  Amendment No. 3, dated
     November 18, 1994, Amendment No. 4, dated November 22, 1994,
     Amendment No. 5, dated November 23, 1994,  Amendment No. 6, dated
     November 29, 1994, Amendment No. 7, dated December 2, 1994,
     Amendment No. 8, dated December 8, 1994, Amendment No. 9, dated
     December 15, 1994, Amendment No. 10, dated December 16, 1994, and
     Amendment No. 11, dated December 19, 1994, with respect to the
     Purchaser's offer to purchase 115,903,127 shares of Common Stock,
     par value $1.00 per share (the "Shares"), of Santa Fe Pacific
     Corporation, a Delaware corporation (the "Company").

          Unless otherwise indicated herein, each capitalized term
     used but not defined herein shall have the meaning assigned to
     such term in Schedule 14D-1 or in the Offer to Purchase referred
     to therein.

     ITEM 3.  PAST CONTACTS, TRANSACTIONS OR NEGOTIATIONS WITH
             THE SUBJECT COMPANY.

          The information set forth in Item 3(b) of Schedule 14D-1 is
     hereby amended and supplemented by the following information:

          On December 20, 1994, Parent issued a press release
     announcing that Parent was reviewing its options concerning its
     proposal to acquire the Company.  The press release also
     announced that Drew Lewis, Chairman and Chief Executive Officer
     of Parent, sent a letter, dated December 20, 1994, to the
     Company.  A copy of the press release and the letter are attached
     hereto as Exhibit (a)(25) and incorporated herein by reference.

     ITEM 11.  MATERIAL TO BE FILED AS EXHIBITS.

          (a)(25)   Text of Press Release issued by Union Pacific
                    Corporation on December 20, 1994.


                                 SIGNATURE

          After due inquiry and to the best of my knowledge and
     belief, I certify that the information set forth in this
     statement is true, complete and correct.

     Dated:  December 22, 1994

                                     UNION PACIFIC CORPORATION

                                     By: /s/ Gary M. Stuart
                                        __________________________
                                     Title: Vice President and 
                                              Treasurer



                                 SIGNATURE

          After due inquiry and to the best of my knowledge and
     belief, I certify that the information set forth in this
     statement is true, complete and correct.

     Dated:  December 22, 1994

                                     UP ACQUISITION CORPORATION

                                     By: /s/ Gary M. Stuart
                                         _______________________
                                     Title: Vice President and 
                                              Treasurer




                               EXHIBIT INDEX

     Exhibit No.         Description

          (a)(25)   Text of Press Release issued by Union Pacific
                    Corporation on December 20, 1994.





                                                    EXHIBIT (A)(25)

          (UNION PACIFIC            NEWS RELEASE
          CORPORATION - LOGO)

                                    Contact:  610-861-3382
                                    Gary F. Schuster
                                    Vice President - Corporate Relations
                                    Martin Tower
                                    Eighth and Eaton Avenues
                                    Bethlehem, PA  18018

                                              FOR IMMEDIATE RELEASE

              UNION PACIFIC TO REVIEW OPTIONS REGARDING SANTA FE

          BETHLEHEM, PA, DECEMBER 20, 1994 -- Union Pacific
          Corporation (NYSE: UNP) said today that it was reviewing
          its options concerning its proposal to acquire Santa Fe
          Pacific Corporation (NYSE: SFX).

               Drew Lewis, Chairman and CEO of Union Pacific, said
          in a letter today to Robert Krebs, Chairman and CEO of
          Santa Fe, "The recent actions of Santa Fe are but a
          continuation of Santa Fe's ongoing efforts to pursue its
          sale to Burlington Northern, and to prevent a transaction
          with Union Pacific, at all costs.  We object to Santa Fe's
          grant of "lock-ups" to Burlington Northern to deter
          competing bids, and to Santa Fe's repeated refusal to
          address our objections to its flawed sales process."

               Mr. Lewis added, "With regard to Santa Fe's efforts
          to deter competing bids, we note with interest that a
          Burlington Northern representative, who would speak only
          on the condition of anonymity, was quoted today in the
          press as stating:  'This is a carefully crafted plan
          designed to accomplish the merger and to make it
          prohibitively expensive for UP to top.'"

               The text of Lewis' December 20 letter to Krebs, and
          Lewis' December 18 letter sent to Krebs prior to the
          revised sale agreement with Burlington Northern Inc.
          (NYSE: BNI) are attached.

                                   *   *   *

                                        December 20, 1994

          Mr. Robert D. Krebs
          Chairman, President and CEO
          Santa Fe Pacific Corporation
          1700 East Golf Road
          Schaumberg, IL  60173

          Dear Rob:

               The recent actions of Santa Fe are but a continuation
          of Santa Fe's ongoing efforts to pursue its sale to
          Burlington Northern, and to prevent a transaction with
          Union Pacific, at all costs.

               We object to Santa Fe's grant of "lock-ups" to
          Burlington Northern to deter competing bids, and to Santa
          Fe's repeated refusal to address our objections to its
          flawed sales process.

               With regard to Santa Fe's efforts to deter competing
          bids, we note with interest that a Burlington Northern
          representative, who would speak only on the condition of
          anonymity, was quoted today in the press as stating: 
          "This is a carefully crafted plan designed to accomplish
          the merger and to make it prohibitively expensive for UP
          to top."

               As we have announced, we will be reviewing our
          options concerning our acquisition proposal.

                                        Sincerely,

                                        /s/ Drew Lewis


                                   *   *   *

                                        December 18, 1994

          Mr. Robert D. Krebs
          Chairman, President and CEO
          Santa Fe Pacific Corporation
          1700 East Golf Road
          Schaumburg, IL  60173

          Dear Rob:

                    I understand that you sent a letter to my office
          Saturday.

                    We continue to be troubled by Santa Fe's refusal
          to address in any way our concerns about your process for
          considering acquisition proposals.

                    As we have repeatedly stated, and said to your
          advisors yesterday, we want to be in a position to make an
          improved proposal.  We see no reason why you cannot
          address our concerns, and hope you will give consideration
          to the specific suggestions made by our advisors.

                                        Sincerely,

                                        /s/ Drew Lewis