**Exhibit      10.6**

**LETTER      AGREEMENT**

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|         |                                                                                                                                                                                        |                                              |
|--------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------|
|         |                                                                                                                                                                                        | **IMTT HOLDINGS INC.**                            |
|    |                                                                                                                                                                                   |                                         |
|         |                                                                                                                                                                                        | By:               /s/ THOMAS B. COLEMAN |
|         | 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                                                                                                                                                           |
|         | 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                                                                                                                                                      |
|         | THOMAS              B. COLEMAN, TRUSTEE                                                                                                                                                     |
|         |                                                                                                                                                                                        |
|         |                                                                                                                                                                                        |
|         |                                                                                                                                                                                        |
|         | By: /s/              JAMES J. COLEMAN JR.                                                                                                                                                   |
|         | JAMES              J. COLEMAN JR., TRUSTEE                                                                                                                                                  |
|         |                                                                                                                                                                                        |
|         |                                                                                                                                                                                        |
|         |                                                                                                                                                                                        |
|         | By: /s/              JAMES O. COLEMAN                                                                                                                                                       |
|         | JAMES              O. COLEMAN, TRUSTEE                                                                                                                                                      |

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