EXHIBIT 10.4

                               FIRST AMENDMENT TO
                            TRANCHE B LOAN AGREEMENT

          This  FIRST AMENDMENT TO TRANCHE B LOAN AGREEMENT, dated as of October
15,  2001  (this  "Amendment")  is among BRL UNIVERSAL EQUIPMENT 2001 A, L.P., a
                   ---------
Delaware  limited  partnership  ("Borrower"), the several financial institutions
                                  --------
listed  on  the  signature pages hereof as Tranche B Lenders, (each a "Tranche B
                                                                       ---------
Lender"  and  collectively  "Tranche  B  Lenders"),  BANKERS  TRUST  COMPANY, as
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Administrative  Agent  for  Tranche B Lenders (in such capacity, "Administrative
                                                                  --------------
Agent")  and  BANKERS  TRUST  COMPANY,  as  Collateral  Agent (in such capacity,
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"Collateral  Agent").
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                              W I T N E S S E T H:
                              - - - - - - - - - -

          WHEREAS,  Borrower, Administrative Agent, Collateral Agent and Tranche
B  Lenders  have  entered into that certain Tranche B Loan Agreement dated as of
February  9,  2001  (together  with  all amendments and supplements thereto, the
"Tranche  B  Loan  Agreement");  and
 ---------------------------

          WHEREAS,  the  parties  hereto desire to amend certain Sections of the
Tranche  B  Loan  Agreement.

          NOW, THEREFORE, in consideration of the premises and mutual agreements
contained herein and in the Participation Agreement, the parties hereto agree as
follows:

          1.     Definitions. Unless the context otherwise requires, capitalized
                 -----------
terms used herein and not otherwise defined herein shall have meanings set forth
or  referred  to  in  Appendix A to the First Amended and Restated Participation
Agreement  dated  as  of  October 15, 2001 (the "Participation Agreement") among
                                                 -----------------------
Universal  Compression Inc., Universal Compression Holdings, Inc., Borrower, The
Bank  of  New York, the Tranche B Lenders party thereto, BRL Universal Equipment
Management,  Inc.,  Administrative  Agent and Collateral Agent, which Appendix A
also  contains  the  rules  of  usage  that  shall  apply  hereto.

          2.     Effectiveness.  This Amendment shall become effective as of the
                 -------------
date first written above upon (i) the execution and delivery hereof by Majority
Tranche B Lenders, Lessee and Borrower and (ii) the First Amended and Restated
Participation Agreement becoming effective in accordance with the terms thereof.

          3.     Amendments.
                 ----------

               (a)  The introductory paragraph is hereby amended and restated as
     follows:

                    This  TRANCHE B LOAN AGREEMENT, dated as of February 9, 2001
          (the  "Agreement")  is  among  BRL UNIVERSAL EQUIPMENT 2001 A, L.P., a
                 ---------
          Delaware  limited  partnership  ("Borrower"),  the  several  financial
                                            --------
          institutions listed on the signature pages hereof as Tranche B Lenders
          or  who became party to the Participation Agreement (as defined below)


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          in  accordance  with  its  terms  (each  a  "Tranche  B  Lender"  and
                                                       ------------------
          collectively  "Tranche  B  Lenders"),  BANKERS  TRUST  COMPANY,  as
          Administrative  Agent  for  Tranche  B  Lenders  (in  such  capacity,
          "Administrative Agent") and BANKERS TRUST COMPANY, as Collateral Agent
           -------------------
          (in  such  capacity,  "Collateral  Agent").
                                 -----------------

               (b)  Section  2.1  is  hereby  amended  and  restated as follows:

                    "Subject  to  and upon the terms and conditions set forth in
          this  Agreement and the Participation Agreement, each Tranche B Lender
          agrees  to  make  one  or  more non-revolving loans in accordance with
          Section  4.1  of  the  Participation  Agreement."

               (c)  Section  2.2(b)  is  hereby amended and restated as follows:

                    "Each  Tranche B Note issued to a Tranche B Lender shall (i)
          be  executed  by Borrower, (ii) be payable to such Tranche B Lender or
          registered assigns and be dated the Funding Date therefor, (iii) be in
          a stated principal amount equal to the principal amount funded by such
          Tranche  B  Lender  on  such Funding Date, (iv) mature on the Maturity
          Date,  (v) bear interest as provided in Section 2.3.2, (vi) be subject
          to  mandatory  repay-ment  as  provided  in  Section  2.5 and (vii) be
          entitled  to  the  benefits  of this Agreement and the other Operative
          Documents."

               (d)  Section  2.3.2  is  hereby  amended and restated as follows:

                    "Borrower  agrees  to  pay  to each Tranche B Lender on each
          Floating  Payment Date interest accrued on the unpaid principal amount
          of  such  Tranche  B Lender's Tranche B Loan (or Tranche B Loans) from
          the  date the proceeds thereof are disbursed to Borrower in accordance
          with Section 2.2 until the date on which such Tranche B Loan (together
          with  accrued  and unpaid interest thereon) is repaid in full (whether
          on  the Maturity Date, by acceleration or otherwise) at the Applicable
          Tranche  B  Rate calculated for each day elapsed since the immediately
          preceding  Floating Payment Date, or in the case of the first Floating
          Payment  Date  following  the making of such Tranche B Loan, since the
          Funding  Date  therefor  as  follows:


                                      -2-
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               AR x P x 1/D

               where,

               AR  =  the  Applicable Tranche B Rate for such Tranche B Loan for
     such  day;

               P   =  the  unpaid  principal  balance  of such Tranche B Loan on
     such day;  and

               D   =  360 or, to the extent the Applicable Tranche B Rate is
     based on the Alternate Rate, 365 or 366 days, as applicable."

          4.   Authorization.  By  executing and delivering this Amendment, each
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Lender  hereby  authorizes and instructs Collateral Agent to execute and deliver
the  First  Amended and Restated Participation Agreement and the First Amendment
to  Equipment  Lease  Agreement,  in  each  case,  of  even  date  herewith.

          5.   Miscellaneous.  Sections  6.1,  6.2,  6.5,  6.7,  6.8, 6.10, 6.11
               -------------
and  6.12  of  the Tranche B Loan Agreement are incorporated herein by reference
mutatis  mutandis.


                                      -3-
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          IN  WITNESS  WHEREOF, the parties hereto have caused this Amendment to
be  duly  executed and delivered by their respective duly authorized officers as
of  the  date  first  above  written.

                                    BRL  UNIVERSAL  EQUIPMENT  2001  A,  L.P.,
                                       as Borrower

                                    By BRL Universal Equipment Management, Inc.
                                    Its  General  Partner

                                    By: /s/  Gregory C. Greene
                                       -------------------------------
                                       President


                                    BANKERS  TRUST  COMPANY
                                       as Administrative Agent

                                    By: /s/  Calli S. Hayes
                                       -------------------------------
                                       Managing  Director


                                    BANKERS  TRUST  COMPANY
                                       as Collateral Agent

                                    By: /s/  Calli  S.  Hayes
                                       -------------------------------
                                       Managing  Director


                                    FIRST  UNION  NATIONAL  BANK
                                       as a Tranche B Lender

                                    By: /s/  David E. Humphreys
                                       -------------------------------
                                       Vice  President


                                    BANK  ONE,  NA
                                       (Main  Office  Chicago)
                                        as a Tranche B Lender

                                    By: /s/  Dianne L. Russell
                                       -------------------------------
                                       Vice  President


                                -Signature Page-
                  [First Amendment to Tranche B Loan Agreement]

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                                    THE  BANK  OF  NOVA  SCOTIA
                                       as  a  Tranche  B  Lender

                                    By: /s/  F.C.H.  Ashby
                                       -------------------------------
                                       Senior Manager, Loan Operations


                                    CITADEL  HILL  2000  Ltd.,
                                       as  a  Tranche  B  Lender

                                    By: /s/  Stephen  Lockhart
                                       ----------------------------------
                                       Authorized  Signatory


                                    NATEXIS  BANQUES  POPULAIRES
                                       as  a  Tranche  B  Lender

                                    By:
                                       ----------------------------------
                                       Name:
                                       Title:


                                    LANDMARK  CDO  LIMITED,
                                       as  Tranche  B  Lender

                                    By:  Aladdin Asset Management
                                         LLC, as Manager

                                    By  /s/ Gilles Marchand
                                       -------------------------------
                                       Authorized  Signatory


                                    CSAM  FUNDING  I,
                                       as  Tranche  B  Lender

                                    By
                                       -------------------------------
                                       Name:
                                       Title:


                                    FIRST  DOMINION  FUNDING  I,
                                       as  Tranche  B  Lender

                                    By
                                       -------------------------------
                                       Name:
                                       Title:


                                    FIRST  DOMINION  FUNDING  II,
                                       as  Tranche  B  Lender

                                    By
                                       -------------------------------
                                       Name:
                                       Title:



                                -Signature Page-
                  [First Amendment to Tranche B Loan Agreement]

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