<PAGE>
                                                                    EXHIBIT 10.6


                                                                         ANNEX A


                      UNIVERSAL COMPRESSION HOLDINGS, INC.
                           UNIVERSAL COMPRESSION, INC.
                              4440 BRITTMOORE ROAD
                              HOUSTON, TEXAS 77041


                                                                October 16, 2001


Deutsche Banc Alex. Brown Inc.
First Union Securities, Inc.
Banc One Capital Markets, Inc.
Scotia Capital (USA) Inc.
c/o    Deutsche Banc Alex. Brown Inc.
       130 Liberty Street
       New York, New York  10006

               Re: Universal Compression Synthetic Lease Financing

Ladies and Gentlemen:

                  Reference is made to that certain letter agreement dated
January 21, 2001 among Deutsche Banc Alex. Brown Inc. ("DBAB"), BRL Universal
Equipment 2001 A, L.P. ("BRL"), BRL Universal Equipment Corp. ("BRLC") and
Universal Compression, Inc. (the "Company") (the "Letter Agreement") and the
indemnity letter referred to in Section 3(c) thereof (the "Indemnity Letter")
(the Letter Agreement and the Indemnity Letter (not including the supplement
thereto dated February 6, 2001) are referred to collectively herein as the
"Engagement Letter"). Capitalized terms used herein without definition have the
meanings given such terms in the Engagement Letter.

                  In consideration of (i) the intention of BRL to acquire
additional domestic gas compression equipment with an aggregate appraised value
of at least $122.0 million from the Company and (ii) the intention of BRL, BRLC
UCH and UCI to raise additional funds of $122.0 million in the aggregate
pursuant to the provisions of the documents governing the Financing to finance
the acquisition of the additional equipment, the parties to the Engagement
Letter wish to execute this letter agreement (this "Agreement") supplementing
certain provisions of the Engagement Letter. Contemporaneously herewith the
Initial Purchasers are entering into a purchase agreement with BRL and BRLC (the
"Purchase Agreement") relating to the purchase of $100,000,000 aggregate
principal amount of 8-7/8% Senior Secured Notes

<PAGE>
                                      -2-

due 2008 of BRL and BRLC (the "Notes") offered pursuant to the offering
memorandum dated the date hereof prepared by UCH, UCI, BRL and BRLC (the
"Memorandum").

                  Section 1. Representations and Warranties. Each of UCH and
UCI, severally and jointly, represents and warrants to (provided, each such
representation and warranty shall be true and correct on the date hereof and at
and as of the Closing Date unless expressly stated to relate to another date)
and agrees with each of the Initial Purchasers that:

                  (a) Neither the Memorandum nor any amendment or supplement
         thereto as of the date thereof and at all times subsequent thereto up
         to the Closing Date (as defined in the Purchase Agreement) contained or
         contains any untrue statement of a material fact or omitted or omits to
         state a material fact necessary to make the statements therein, in
         light of the circumstances under which they were made, not misleading,
         except that the representations and warranties set forth in this
         Section 1(a) do not apply to the Initial Purchaser Information or the
         Issuer Information.

                  (b) The audited and unaudited consolidated financial
         statements of UCH and UCI included or incorporated by reference into
         the Memorandum present fairly in all material respects the financial
         position, results of operations and cash flows of each of UCH and UCI
         at the respective dates and for the respective periods to which they
         relate and have been prepared in accordance with generally accepted
         accounting principles applied on a consistent basis, except as
         otherwise stated therein. Deloitte & Touche LLP, and, to the knowledge
         of UCI and UCH, Arthur Andersen LLP and KPMG LLP (the "Independent
         Accountants") are independent public accounting firms within the
         meaning of the Act and the rules and regulations promulgated thereunder

                  (c) The pro forma financial statements (including the notes
         thereto) and the other pro forma financial information included or
         incorporated by reference in the Memorandum (i) comply as to form in
         all material respects with the applicable requirements of Regulation
         S-X promulgated under the Exchange Act, (ii) have been prepared in all
         material respects in accordance with the Commission's rules and
         guidelines with respect to pro forma financial statements, and (iii)
         have been properly computed on the bases described therein; the
         assumptions used in the preparation of the pro forma financial data and
         other pro forma financial information included in the Memorandum are
         reasonable and the adjustments used therein are appropriate in all
         material respects to give effect to the transactions or circumstances
         referred to therein.

                  (d) The statistical and market-related data included in the
         Memorandum are based on or derived from sources which UCH and UCI
         believe to be in all material respects reliable and accurate.

<PAGE>
                                      -3-


                  (e) Neither UCH nor UCI nor any agent acting on their behalf
         has taken or will take any action that might cause this Agreement or
         the sale of the Notes to violate Regulation T, U or X of the Board of
         Governors of the Federal Reserve System, in each case as in effect on
         the Closing Date.

                  (f) Each of UCH and UCI (i) makes and keeps books and records
         which, in reasonable detail, accurately and fairly reflect the
         transactions and disposition of assets of such entity and (ii)
         maintains internal accounting controls which provide reasonable
         assurance that (A) transactions are executed in accordance with
         management's general or specific authorization, (B) transactions are
         recorded as necessary to permit preparation of its financial statements
         and to maintain accountability for its assets, (C) access to its assets
         is permitted only in accordance with management's authorization and (D)
         the reported accountability for its assets is compared with existing
         assets at reasonable intervals.

                  (g) The Notes, the Indenture, the Registration Rights
         Agreement (as defined in the Memorandum) and each of the Operative
         Documents (as defined in the Memorandum) will conform in all material
         respects to the descriptions thereof in the Memorandum.

                  (h) No holder of securities of UCH or UCI will be entitled to
         have such securities registered under the registration statements
         required to be filed pursuant to the Registration Rights Agreement (as
         defined in the Memorandum) other than as expressly permitted thereby.

                  (i) Neither UCH nor UCI nor any of their respective affiliates
         as defined in Rule 501(b) of Regulation D under the Act ("Affiliates")
         have directly, or through any agent, (i) sold, offered for sale,
         solicited offers to buy or otherwise negotiated in respect of any
         "security" (as defined in the Act) which is or could be integrated with
         the sale of the Notes in a manner that would require the registration
         under the Act of the Notes or (ii) engaged in any form of general
         solicitation or general advertising (as those terms are used in
         Regulation D under the Act) in connection with the offering of the
         Notes or in any manner involving a public offering within the meaning
         of Section 4(2) of the Act.

                  (j) Neither UCH nor UCI has taken, nor will it take, directly
         or indirectly, any action designed to, or that might be reasonably
         expected to, cause or result in stabilization or manipulation of the
         price of the Notes.

                  (k) Neither UCH nor UCI nor any of their Affiliates or any
         person acting on its or their behalf (other than the Initial
         Purchasers) has engaged in any directed


<PAGE>
                                      -4-


         selling efforts (as that term is defined in Regulation S under the Act
         ("Regulation S")) with respect to the Notes.

                  (l) On the Closing Date, all the representations and
         warranties made by UCH and UCI in the Participation Agreement (as
         defined in the Memorandum) shall be true and correct.

                  (m) This Agreement and the Registration Rights Agreement have
         been duly authorized, executed and delivered by each of UCH and UCI.

                  Section 2. Covenants. Each of UCH and UCI covenants and
agrees, jointly and severally, with each of the Initial Purchasers that:

                  (a) UCH and UCI will not amend or supplement the Memorandum or
         any amendment or supplement thereto of which the Initial Purchasers
         shall not previously have been advised and furnished a copy for a
         reasonable period of time prior to the proposed amendment or supplement
         and as to which the Initial Purchasers shall reasonably object to in
         writing; any objection to such amendment or supplement shall be made
         within two business days after receiving a draft copy thereof. UCH and
         UCI will promptly, upon the reasonable request of the Initial
         Purchasers or counsel for the Initial Purchasers, make any amendments
         or supplements to the Memorandum that may be necessary or advisable in
         connection with the resale of the Notes by the Initial Purchasers.

                  (b) If, at any time prior to the completion of the
         distribution by the Initial Purchasers of the Notes or the Private
         Exchange Notes (as defined in the Registration Rights Agreement), any
         event occurs or information becomes known as a result of which the
         Memorandum as then amended or supplemented would include any untrue
         statement of a material fact, or omit to state a material fact
         necessary to make the statements therein, in the light of the
         circumstances under which they were made, not misleading, or if for any
         other reason it is necessary at any time to amend or supplement the
         Memorandum to comply with applicable law, UCH and UCI will promptly
         notify the Initial Purchasers thereof and will prepare, at the expense
         of UCH and UCI, an amendment or supplement to the Memorandum that
         corrects such statement or omission or effects such compliance.

                  (c) UCH and UCI will, without charge, provide to the Initial
         Purchasers and to counsel for the Initial Purchasers as many copies of
         the Memorandum or any amendment or supplement thereto as the Initial
         Purchasers may reasonably request.

<PAGE>
                                      -5-


                  (d) For a period of one year after the Closing Date, UCH and
         UCI will furnish to the Initial Purchasers copies of any reports or
         financial statements furnished to or filed by UCH or UCI with the
         Commission or any national securities exchange on which any class of
         securities of UCH or UCI may be listed.

                  (e) For so long as any of the Notes remain outstanding and
         have not been registered pursuant to the Act, UCH and UCI will make
         available at their expense, upon reasonable request, to any holder of
         such Notes and any prospective purchasers thereof the information
         specified in Rule 144A(d)(4) under the Act, unless UCH or UCI, as the
         case may be, are subject to Section 13 or 15(d) of the Exchange Act.

                  Section 3. Conditions Precedent. The obligation of the Initial
Purchasers to fulfill any obligation to BRL and BRLC as contemplated by the
Purchase Agreement shall, in the sole discretion of the Initial Purchasers, be
subject to the satisfaction or waiver of the following conditions on or prior to
the Closing Date (and BRL and BRLC so agree):

                  (a) The Initial Purchasers shall have received a certificate
         of each of UCH and UCI, dated the Closing Date and addressed to BRL and
         the Initial Purchasers, signed on behalf of UCH and UCI by their
         respective duly authorized officers to the effect that:

                           (i) The representations and warranties of UCH and UCI
                  contained in this Agreement are true and correct in all
                  material respects on and as of the Closing Date, and UCH and
                  UCI have performed in all material respects all covenants and
                  agreements and satisfied all conditions on their part to be
                  performed or satisfied hereunder at or prior to the Closing
                  Date;

                           (ii) At the Closing Date, since the date of the
                  Memorandum or since the date of the most recent financial
                  statements in the Memorandum (exclusive of any amendment or
                  supplement thereto after the date of the Memorandum), no event
                  or development has occurred, and no information has become
                  known, that, individually or in the aggregate, has or would
                  reasonably be expected to have a material adverse effect on
                  the business, condition (financial or otherwise) or results of
                  operations of UCH and UCI, taken as a whole (any such event, a
                  "Material Adverse Effect"); and

                           (iii) The sale of the Notes has not been enjoined
                  (temporarily or permanently).

                  (b) On the Closing Date, the Initial Purchasers shall have
         received the opinions to be delivered to the parties pursuant to the
         Participation Agreement, dated

<PAGE>
                                      -6-


         as of the Closing Date and addressed to the Initial Purchasers, of King
         & Spalding, Gardere Wynne Sewell LLP and Mark Carlton, counsel for UCH
         and UCI, in form and substance satisfactory to counsel for the Initial
         Purchasers.

                  (c) The representations and warranties of each of UCH and UCI
         contained in this Agreement shall be true and correct on and as of the
         date hereof and on and as of the Closing Date in all material respects
         as if made on and as of the Closing Date; the statements of the
         officers of UCH or UCI made pursuant to any certificate delivered in
         accordance with the provisions hereof shall be true and correct in all
         material respects on and as of the date made and on and as of the
         Closing Date; each of UCH and UCI shall have performed in all material
         respects all covenants and agreements and satisfied all conditions on
         its part to be performed or satisfied hereunder at or prior to the
         Closing Date; and, except as described in the Memorandum (exclusive of
         any amendment or supplement thereto after the date hereof), subsequent
         to the date of the most recent financial statements in such Memorandum,
         there shall have been no event or development, and no information shall
         have become known, that, individually or in the aggregate, has or would
         reasonably be expected to have a Material Adverse Effect.

                  (d) Subsequent to the date of the most recent financial
         statements of UCH or UCI incorporated by reference in the Memorandum
         (exclusive of any amendment or supplement thereto after the date
         hereof), neither UCH nor UCI shall have sustained any loss or
         interference with respect to its business or properties from fire,
         flood, hurricane, accident or other calamity, whether or not covered by
         insurance, or from any strike, labor dispute, slowdown or work stoppage
         or from any legal or governmental proceeding, order or decree, which
         loss or interference, individually or in the aggregate, has or would
         reasonably be expected to have a Material Adverse Effect.

                  (e) On the Closing Date, the Initial Purchasers shall have
         received the Registration Rights Agreement executed by UCH and UCI and
         the other parties thereto.

                  (f) On the Closing Date, all conditions of UCH or UCI to the
         consummation of the transactions contemplated by the Operative
         Documents shall have been satisfied and each Operative Document shall
         be in full force and effect as to UCH and UCI. Since the date of this
         Agreement, except in connection with the offering of the Notes or as
         previously disclosed to the Initial Purchasers and reasonably
         acceptable to them, there have been no amendments, modifications,
         restatements or waivers to any Operative Documents which would be
         required to be disclosed in the Memorandum and are not so disclosed.

<PAGE>
                                      -7-

                  On or before the Closing Date, the Initial Purchasers and
counsel for the Initial Purchasers shall have received such further documents,
opinions, certificates, letters and schedules or instruments relating to the
business, corporate, legal and financial affairs of UCH and UCI as they shall
have heretofore reasonably requested from UCH and UCI.

                  All such documents, opinions, certificates, letters, schedules
or instruments delivered pursuant to this Agreement will comply with the
provisions hereof only if they are reasonably satisfactory in all material
respects to the Initial Purchasers and counsel for the Initial Purchasers. UCH
and UCI shall furnish to the Initial Purchasers such conformed copies of such
documents, opinions, certificates, letters, schedules and instruments in such
quantities as the Initial Purchasers shall reasonably request.

                  Section 4.  Indemnification and Contribution.

                  (a) UCH and UCI agree to indemnify and hold harmless the
Initial Purchasers and each person, if any, who controls any Initial Purchaser
within the meaning of Section 15 of the Securities Act of 1933, as amended (the
"Act") or Section 20 of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), against any losses, claims, damages or liabilities to which any
Initial Purchaser or such controlling person may become subject under the Act,
the Exchange Act or otherwise, insofar as any such losses, claims, damages or
liabilities (or actions in respect thereof) arise out of or are based upon:

                  (i) any untrue statement or alleged untrue statement of any
         material fact contained in any Memorandum or any amendment or
         supplement thereto; or

                  (ii) the omission or alleged omission to state, in any
         Memorandum or any amendment or supplement thereto, a material fact
         required to be stated therein or necessary to make the statements
         therein, in light of the circumstances under which they were made, not
         misleading

and will reimburse, as incurred, the Initial Purchasers and each such
controlling person for any legal or other expenses reasonably incurred by the
Initial Purchasers or such controlling person in connection with investigating,
defending against or appearing as a third-party witness in connection with any
such loss, claim, damage, liability or action; provided, however, UCH and UCI
will not be liable in any such case to the extent that any such loss, claim,
damage, or liability arises out of or is based upon any untrue statement or
alleged untrue statement or omission or alleged omission made in the Memorandum
or any amendment or supplement thereto in reliance upon and in conformity with
written information concerning the Initial Purchasers furnished to UCH or UCI,
as the case may be, by the Initial Purchasers specifically for use therein. This
indemnity agreement will be in addition to any liability that UCH or UCI may
otherwise have to the indemnified parties. UCH and UCI shall not be liable under
this

<PAGE>
                                      -8-

Section 4 for any settlement of any claim or action effected without their
prior written consent, which shall not be unreasonably withheld, delayed or
conditioned. The Initial Purchasers shall not, without the prior written consent
of UCH and UCI, effect any settlement or compromise of any pending or threatened
proceeding in respect of which UCH and UCI are or could have been a party, or
indemnity could have been sought hereunder by UCH and UCI, unless such
settlement (A) includes an unconditional written release of UCH and UCI, in form
and substance reasonably satisfactory to UCH and UCI, from all liability on
claims that are the subject matter of such proceeding and (B) does not include
any statement as to an admission of fault, culpability or failure to act by or
on behalf of UCH and UCI.

                  (b) The Initial Purchasers agree to indemnify and hold
harmless UCH and UCI, their respective directors, officers and each person, if
any, who controls UCH and UCI within the meaning of Section 15 of the Act or
Section 20 of the Exchange Act against any losses, claims, damages or
liabilities to which UCH and UCI or any such director, officer or controlling
person may become subject under the Act, the Exchange Act or otherwise, insofar
as such losses, claims, damages or liabilities (or actions in respect thereof)
arise out of or are based upon (i) any untrue statement or alleged untrue
statement of any material fact contained in the Memorandum or any amendment or
supplement thereto, or (ii) the omission or the alleged omission to state
therein a material fact required to be stated in the Memorandum or any amendment
or supplement thereto, or necessary to make the statements therein not
misleading, in each case to the extent, but only to the extent, that such untrue
statement or alleged untrue statement or omission or alleged omission was made
in reliance upon and in conformity with written information concerning such
Initial Purchaser, furnished to UCH or UCI, as the case may be, by the Initial
Purchasers specifically for use therein; and subject to the limitation set forth
immediately preceding this clause, will reimburse, as incurred, any legal or
other expenses reasonably incurred by UCH or UCI or any such director, officer
or controlling person in connection with investigating or defending against or
appearing as a third party witness in connection with any such loss, claim,
damage, liability or action in respect thereof. This indemnity agreement will be
in addition to any liability that the Initial Purchasers may otherwise have to
the indemnified parties. The Initial Purchasers shall not be liable under this
Section 4 for any settlement of any claim or action effected without their
consent, which shall not be unreasonably withheld. Neither UCH nor UCI shall,
without the prior written consent of the Initial Purchasers, effect any
settlement or compromise of any pending or threatened proceeding in respect of
which any Initial Purchaser is or could have been a party, or indemnity could
have been sought hereunder by any Initial Purchaser, which settlement or
compromise would be applicable to the Initial Purchasers unless such settlement
(A) includes an unconditional written release of the Initial Purchasers, in form
and substance reasonably satisfactory to the Initial Purchasers, from all
liability on claims that are the subject matter of such proceeding and (B) does
not include any statement as to an admission of fault, culpability or failure to
act by or on behalf of any Initial Purchaser.

<PAGE>
                                      -9-


                  (c) Promptly after receipt by an indemnified party under this
Section 4 of notice of the commencement of any action for which such indemnified
party is entitled to indemnification under this Section 4, such indemnified
party will, if a claim in respect thereof is to be made against the indemnifying
party under this Section 4, notify the indemnifying party of the commencement
thereof in writing; but the omission to so notify the indemnifying party (i)
will not relieve it from any liability under paragraph (a) or (b) above unless
and to the extent such failure results in the forfeiture by the indemnifying
party of substantive rights and defenses and (ii) will not, in any event,
relieve the indemnifying party from any obligations to any indemnified party
other than the indemnification obligation provided in paragraphs (a) and (b)
above. In case any such action is brought against any indemnified party, and it
notifies the indemnifying party of the commencement thereof, the indemnifying
party will be entitled to participate therein and, to the extent that it may
wish, jointly with any other indemnifying party similarly notified, to assume
the defense thereof, with counsel reasonably satisfactory to such indemnified
party; provided, however, that if (i) the use of counsel chosen by the
indemnifying party to represent the indemnified party would present such counsel
with a conflict of interest, (ii) the defendants in any such action include both
the indemnified party and the indemnifying party and the indemnified party shall
have been advised by counsel in writing that there may be one or more legal
defenses available to it and/or other indemnified parties that are different
from or additional to those available to the indemnifying party, or (iii) the
indemnifying party shall not have employed counsel reasonably satisfactory to
the indemnified party to represent the indemnified party within a reasonable
time after receipt by the indemnifying party of notice of the institution of
such action, then, in each such case, the indemnifying party shall not have the
right to direct the defense of such action on behalf of such indemnified party
or parties and such indemnified party or parties shall have the right to select
separate counsel to defend such action on behalf of such indemnified party or
parties. After notice from the indemnifying party to such indemnified party of
its election so to assume the defense thereof and approval by such indemnified
party of counsel appointed to defend such action, the indemnifying party will
not be liable to such indemnified party under this Section 4 for any legal or
other expenses, other than reasonable costs of investigation, subsequently
incurred by such indemnified party in connection with the defense thereof,
unless (i) the indemnified party shall have employed separate counsel in
accordance with the proviso to the immediately preceding sentence (it being
understood, however, that in connection with such action the indemnifying party
shall not be liable for the expenses of more than one separate counsel (in
addition to local counsel) in any one action or separate but substantially
similar actions in the same jurisdiction arising out of the same general
allegations or circumstances, designated by the Initial Purchasers in the case
of paragraph (a) of this Section 4 or UCH or UCI in the case of paragraph (b) of
this Section 4, representing all of the indemnified parties under such paragraph
(a) or paragraph (b), as the case may be, who are parties to such action or
actions) or (ii) the indemnifying party has authorized in writing the employment
of counsel for the indemnified party at the expense of the indemnifying party.
After such notice from the


<PAGE>
                                      -10-

indemnifying party to such indemnified party, the indemnifying party will not be
liable for the costs and expenses of any settlement of such action effected by
such indemnified party without the prior written consent of the indemnifying
party (which consent shall not be unreasonably withheld), unless such
indemnified party waived in writing its rights under this Section 4, in which
case the indemnified party may effect such a settlement without such consent.

                  (d) In circumstances in which the indemnity agreement provided
for in the preceding paragraphs of this Section 4 is unavailable to, or
insufficient to hold harmless, an indemnified party in respect of any losses,
claims, damages or liabilities (or actions in respect thereof), each
indemnifying party, in order to provide for just and equitable contribution,
shall contribute to the amount paid or payable by such indemnified party as a
result of such losses, claims, damages or liabilities (or actions in respect
thereof) in such proportion as is appropriate to reflect (i) the relative
benefits received by the indemnifying party or parties on the one hand and the
indemnified party on the other from the offering of the Notes or (ii) if the
allocation provided by the foregoing clause (i) is not permitted by applicable
law, not only such relative benefits but also the relative fault of the
indemnifying party or parties on the one hand and the indemnified party on the
other in connection with the statements or omissions or alleged statements or
omissions that resulted in such losses, claims, damages or liabilities (or
actions in respect thereof). The relative benefits received by UCH and UCI on
the one hand and any Initial Purchaser on the other shall be deemed to be in the
same proportion as the total proceeds from the offering of the Notes (before
deducting expenses) received bear to the total discounts and commissions or
other compensation received by such Initial Purchaser with respect to the Notes
purchased by such Initial Purchaser. The relative fault of the parties shall be
determined by reference to, among other things, whether the untrue or alleged
untrue statement of a material fact or the omission or alleged omission to state
a material fact relates to information supplied by UCH and UCI on the one hand,
or such Initial Purchaser on the other, the parties' relative intent, knowledge,
access to information and opportunity to correct or prevent such statement or
omission or alleged statement or omission, and any other equitable
considerations appropriate in the circumstances. UCH and UCI and the Initial
Purchasers agree that it would not be equitable if the amount of such
contribution were determined by pro rata or per capita allocation or by any
other method of allocation that does not take into account the equitable
considerations referred to in the first sentence of this paragraph (d).
Notwithstanding any other provision of this paragraph (d), no Initial Purchaser
shall be obligated to make contributions hereunder that in the aggregate exceed
the total discounts, commissions and other compensation received by such Initial
Purchaser, less the aggregate amount of any damages that such Initial Purchaser
has otherwise been required to pay by reason of the untrue or alleged untrue
statements or the omissions or alleged omissions to state a material fact, and
no person guilty of fraudulent misrepresentation (within the meaning of Section
11(f) of the Act) shall be entitled to contribution from any person who was not
guilty of such fraudulent misrepresentation. For purposes of this paragraph (d),
each person, if any, who controls an

<PAGE>
                                      -11-


Initial Purchaser within the meaning of Section 15 of the Act or Section 20 of
the Exchange Act shall have the same rights to contribution as the Initial
Purchasers, and each director of either UCH or UCI, each officer of either UCH
or UCI and each person, if any, who controls either UCH or UCI within the
meaning of Section 15 of the Act or Section 20 of the Exchange Act, shall have
the same rights to contribution as UCH or UCI, as the case may be. The indemnity
and contribution agreements contained in this Section 4 will be in addition to
any liability that the indemnifying parties may otherwise have to the
indemnified parties referred to above.

                  Section 5. Certain Information. The statements set forth in
the third paragraph and the second and third sentences in the fifth paragraph
and the seventh, eighth, ninth and tenth paragraphs under the heading "Private
Placement" in the Memorandum constitute the only information furnished by the
Initial Purchasers to UCH or UCI for the purposes of Sections 1(a) and 4 hereof
(the "Initial Purchaser Information"). The statements set forth in the
penultimate paragraph on page 11 and the last paragraph on page 85 on pages 37,
41, 53 through 55, 74, 75, 83 and F-1 through F-5 constitute the only
information furnished by BRL and BRLC (the "Issuer Information").

                  Section 6. Survival Clause. Notwithstanding anything to the
contrary in the other provisions of the Engagement Letter, the respective
representations, warranties, agreements, covenants, indemnities and other
statements of UCH and UCI, their respective officers and the Initial Purchasers
set forth in this Agreement or made by or on behalf of them pursuant to this
Agreement shall remain in full force and effect, regardless of (i) any
investigation made by or on behalf of UCH or UCI, any of their respective
officers or directors, the Initial Purchasers or any controlling person referred
to in Section 4 hereof and (ii) delivery of and payment for the Notes. The
respective agreements, covenants, indemnities and other statements set forth in
Section 4 hereof shall remain in full force and effect, regardless of any
termination or cancellation of this Agreement.

                  Section 7. Other Agreements; Parties. Upon the execution
hereof by the parties hereto, this Agreement shall be a binding agreement, in
full force and effect, among the parties hereto. The Engagement Letter, as
specifically supplemented hereby, shall continue to be in full force and effect
and is in all respects ratified and confirmed, except with respect to Sections
2(a), 2(b), 2(c), 3(b) and 3(c) thereof, which are terminated and superseded in
their entirety hereby.

                  Section 8. Termination. Notwithstanding anything to the
contrary in the other provisions of the Engagement Letter, the Engagement Letter
shall be deemed to be in full force and effect as supplemented by this
Agreement; provided that this Agreement may be terminated at the same time as
any termination of the Purchase Agreement; provided, however, that the
indemnification provisions hereof set forth in Section 4 shall survive any such
termination as provided in Section 6.



<PAGE>


                                       S-1

                  Please confirm that the foregoing is in accordance with your
understanding by signing and returning to us the enclosed duplicate of this
letter.

                                      Very truly yours,

                                      UNIVERSAL COMPRESSION, INC.


                                      By:    /s/ Richard W. Fitzgerald
                                             -----------------------------------
                                             Richard W. Fitzgerald
                                             Senior Vice President and
                                             Chief Financial Officer



                                      UNIVERSAL COMPRESSION HOLDINGS, INC.


                                      By:    /s/ Richard W. Fitzgerald
                                             -----------------------------------
                                             Richard W. Fitzgerald
                                             Senior Vice President and
                                             Chief Financial Officer

AGREED TO AND ACCEPTED as of the
date first written above:

DEUTSCHE BANC ALEX. BROWN INC.
FIRST UNION SECURITIES, INC.
BANC ONE CAPITAL MARKETS, INC.
SCOTIA CAPITAL (USA) INC.

By:  Deutsche Banc Alex. Brown Inc.


By:    /s/ Steven M. Cowan
       --------------------------------
       Steven M. Cowan
       Vice President


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                                      S-2


BRL UNIVERSAL EQUIPMENT 2001 A, L.P.

By:    BRL Universal Equipment Management, Inc.,
       its General Partner


By:    /s/ Daniel D. Boeckman
       ---------------------------------------------
       Daniel D. Boeckman
       Executive Vice President

BRL UNIVERSAL EQUIPMENT CORP.


By:    /s/ Daniel D. Boeckman
       ---------------------------------------------
       Daniel D. Boeckman
       Executive Vice President