Exhibit 10.6

 
LETTER AGREEMENT

By this Letter Agreement entered into as of July 30, 2007, the Shareholders and
IMTT Holdings Inc. (collectively with its subsidiaries, the “Company”) agree
that from and including the Fiscal Quarter ending on March 31, 2009 through and
including the Fiscal Quarter ending on March 31, 2010, for the purposes only of
Section 4(d) and Section 4(e) of the Shareholders’ Agreement (as defined below),
Net Debt shall be reduced by $125 million.

The Shareholders and the Company further agree that this Letter Agreement
constitutes an amendment to the Shareholders Agreement dated April 14, 2006 (as
amended) between the Shareholders and the Company (the “Shareholders’
Agreement”) and that, except as set forth herein, the Shareholders’ Agreement
shall remain in full force and effect. Capitalized terms in this Letter
Agreement shall be as defined in the Shareholders’ Agreement unless otherwise
defined herein. This Letter Agreement may be executed and delivered (including
by facsimile transmission) in one or more counterparts, each of which when
executed shall be deemed to be an original, but all of which taken together
shall constitute one and the same agreement. This Letter Agreement shall be
governed by, and construed in accordance with, the laws of the State of
Delaware.
 

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          IMTT HOLDINGS INC.  
   
   
      By:  /s/ THOMAS B. COLEMAN  

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Name: THOMAS B. COLEMAN
 
Title: CHIEF EXECUTIVE OFFICER
          SHAREHOLDERS:       MACQUARIE TERMINAL HOLDINGS LLC   By: Macquarie
Infrastructure Company Inc. (d/b/a Macquarie Infrastructure Company (US))      
    By: /s/ PETER STOKES  

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Name: PETER STOKES   Title: CHIEF EXECUTIVE OFFICER           CURRENT BENEFICIAL
SHAREHOLDERS ARE HEREIN REPRESENTED BY:       JAMES J. COLEMAN JR., THOMAS B.
COLEMAN AND JAMES OWEN COLEMAN, TRUSTEES OF VOTING TRUST AGREEMENT DATED MAY 2,
2006 AS AMENDED ON JANUARY 11, 2007.               By: /s/ THOMAS B. COLEMAN  

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THOMAS B. COLEMAN, TRUSTEE               By: /s/ JAMES J. COLEMAN JR.  

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JAMES J. COLEMAN JR., TRUSTEE               By: /s/ JAMES O. COLEMAN  

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JAMES O. COLEMAN, TRUSTEE

 

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