Document:

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                             SUPPLEMENTAL INDENTURE

                  SUPPLEMENTAL INDENTURE (this "SUPPLEMENTAL INDENTURE"), dated
as of September 7, 1999 among Aerolink International, Inc., a Pennsylvania
corporation, Aerolink Maintenance, Inc., a Pennsylvania corporation, Aerolink
Management, Inc., a Pennsylvania corporation, Aerolink International, L.P. a
Pennsylvania limited partnership, (collectively, the "ADDITIONAL GUARANTORS"),
Worldwide Flight Services, Inc., a Delaware corporation (the "COMPANY"),
Worldwide Flight Finance Company, a Delaware corporation, Worldwide Flight
Security Service Corporation, a Delaware corporation, Miami International
Airport Cargo Facilities & Services, Inc., a Florida corporation, (collectively,
the "GUARANTORS") and The Bank of New York, a New York banking corporation, as
trustee under the indenture referred to below (the "TRUSTEE").

                               W I T N E S S E T H

                  WHEREAS, the Company and the Guarantors have heretofore
executed and delivered to the Trustee an indenture (the "INDENTURE"), dated as
of August 12, 1999, providing for the issuance of an aggregate principal amount
of $130,000,000 of 12 1/4% Series A Notes due 2007;

                  WHEREAS, Section 4.23 of the Indenture provides that under
certain circumstances the Company and the Guarantors are required to cause the
Additional Guarantors to execute and deliver to the Trustee a supplemental
indenture pursuant to which the Additional Guarantors shall unconditionally
guarantee all of the Company's Obligations under the Indenture and the
Securities pursuant to a guarantee (the "ADDITIONAL GUARANTEE") on the terms and
conditions of the Guarantee by the Guarantors in Article 11 of the Indenture and
on the other terms and conditions set forth herein; and

                  WHEREAS, pursuant to Section 7.01 of the Indenture, the
Trustee is authorized to execute and deliver this Supplemental Indenture.

                  NOW, THEREFORE, in consideration of the foregoing and for
other good and valuable consideration, the receipt of which is hereby
acknowledged, the parties hereto mutually covenant and agree for the equal and
ratable benefit of the holders of the Securities as follows:

                  1. CAPITALIZED TERMS. Capitalized terms used herein without
definition shall have the meanings assigned to them in the Indenture.

                  2. AGREEMENT TO GUARANTEE. The Additional Guarantors hereby
agree, jointly and severally with all other guarantors, to guarantee the
Company's Obligations under the Indenture and the Securities on the terms and
subject to the conditions set forth herein and in Article 11 of the Indenture
(including the obligation to pay Liquidated Damages under the provisions of the
Registration Rights Agreement) and to be bound by all other applicable
provisions of the Indenture. Pursuant to Section 11.01 of the Indenture, the
Additional Guarantors agree that the Subsidiary Guarantees set forth in Article
11 of the Indenture, as

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supplemented by its agreement to guarantee contained herein shall remain in full
force and effect and apply to all of the Securities notwithstanding any failure
by the Additional Guarantors to endorse on such Securities a notation of the
Subsidiary Guarantor.

                  3. RELEASE OF ADDITIONAL GUARANTOR. In the event that the
holders of any of the Company's other Indebtedness which is guaranteed by the
Additional Guarantors release the Additional Guarantors from its guarantee in
respect of such other Indebtedness, except a discharge or release by or as a
result of any payment under the guarantee of such other Indebtedness by the
Additional Guarantors, the Additional Guarantors shall be automatically and
unconditionally released and discharged from its obligations under this
Additional Guarantee; provided however, if, after such release, any guarantee
under such other Indebtedness is subsequently reincurred or reinstated, then
such Additional Guarantors reincurring or reinstating such guarantee under such
other Indebtedness shall execute and reinstate its Additional Guarantee
hereunder.

                  Upon receipt of an Officers' Certificate, the Trustee shall
execute any documents reasonably requested by the Company, the Guarantors or the
Additional Guarantors in order to evidence the release of such Additional
Guarantors from its obligations under the Additional Guarantee.

                  4. NO RECOURSE AGAINST OTHERS. No direct or indirect
stockholder, employee, officer or director, as such, past, present or future of
the Company, the Guarantors or the Additional Guarantors or any successor entity
shall have any personal liability for any Obligations of the Company, the
Guarantors or the Additional Guarantors or any successor entity under the
Additional Guarantee, by reason of his or its status as such stockholder,
employee, officer or director.

                  Each Holder by accepting a Security waives and releases all
such liability, and such waiver and release is part of the consideration for the
issuance of the Securities.

                  5. GOVERNING LAW. THE INTERNAL LAW OF THE STATE OF NEW YORK
SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE.

                  6. COUNTERPARTS. This Supplemental Indenture may be executed
in any number of counterparts and by the parties hereto in separate
counterparts, each of which when so executed shall be deemed to be an original
and all of which taken together shall constitute one and the same agreement.

                  7. EFFECT OF THE HEADINGS. The Section headings herein are for
convenience only and shall not affect the construction hereof.

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                  IN WITNESS WHEREOF, the parties hereto have caused this
Supplemental Indenture to be duly executed and attested, all as of the date
first above written.

                                              ADDITIONAL GUARANTORS:

                                              AEROLINK INTERNATIONAL, INC.

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name:  Peter A. Pappas
                                                  Title:

                                              AEROLINK MAINTENANCE, INC.

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name:  Peter A. Pappas
                                                  Title:

                                              AEROLINK MANAGEMENT, INC.

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name: Peter A. Pappas
                                                  Title:

                                              AEROLINK INTERNATIONAL, L.P.
                                              by Aerolink Management, Inc., its
                                              General Partner

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name:  Peter A. Pappas
                                                  Title:

                                              COMPANY:

                                              WORLDWIDE FLIGHT SERVICES, INC.

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name:  Peter A. Pappas
                                                  Title:

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                                              GUARANTORS:

                                              WORLDWIDE FLIGHT FINANCE COMPANY

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name:  Peter A. Pappas
                                                  Title:

                                              WORLDWIDE FLIGHT SECURITY SERVICE
                                              CORPORATION

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name:  Peter A. Pappas
                                                  Title:

                                              MIAMI INTERNATIONAL AIRPORT CARGO
                                              FACILITIES & SERVICES, INC.

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name:  Peter A. Pappas
                                                  Title:

                                              INTERNATIONAL ENTERPRISES GROUP,
                                              INC.

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name:  Peter A. Pappas
                                                  Title:

                                              MIAMI AIRCRAFT SUPPORT, INC.

                                              By: /s/ Peter A. Pappas
                                                  -----------------------------
                                                  Name:  Peter A. Pappas
                                                  Title:

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                                          TRUSTEE:

                                          THE BANK OF NEW YORK

                                          By: /s/ VAN K BROWN
                                              -------------------------------
                                              Name: Van K Brown
                                              Title: Assistant Vice President

                                      -5-<PAGE>   1

                                                                     EXHIBIT 4.1

                       THIRD AMENDMENT TO RIGHTS AGREEMENT

         THIS THIRD AMENDMENT TO RIGHTS AGREEMENT (this "Amendment") is made as
of the 13th day of January, 2000, by and between RAILAMERICA, INC., a Delaware
corporation (the "Company"), and AMERICAN STOCK TRANSFER & TRUST COMPANY (the
"Rights Agent").

                                    RECITALS

         WHEREAS, on January 6, 1998, the Board of Directors of the Company
authorized and declared a dividend distribution of one Right for each share of
common stock, $.001 par value, of the Company outstanding at the close of
business on January 20, 1998; and

         WHEREAS, the Company and the Rights Agent entered into a certain Rights
Agreement, dated as of January 6, 1998 as amended September 3, 1998 and April
18, 1999 (the "Rights Agreement"), providing, among other things, for the
issuance of the Rights (all capitalized terms used in this Amendment and not
otherwise defined herein shall have the meanings ascribed to such terms in the
Rights Agreement); and

         WHEREAS, the Board of Directors of the Company has approved the
amendment of the Rights Agreement as hereinafter set forth, pursuant to a
unanimous written consent dated as of January 13, 2000;

         NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         1. Section 1 of the Rights Agreement is hereby amended by deleting the
definition of "Acquiring Person" set forth in subsection (a) thereof in its
entirety and substituting therefor a new definition of "Acquiring Person" to
read as follows:

                  "`Acquiring Person' shall mean any Person who or which,
         together with all Affiliates and Associates of such Person, shall be
         the Beneficial Owner of fifteen percent (15%) or more of the shares of
         Common Stock the outstanding. Notwithstanding the foregoing, the term
         "Acquiring Person" shall not include (i) the Company, any Subsidiary of
         the Company, any employee benefit plan of the Company or of any
         Subsidiary of the Company, or any Person or entity organized, appointed
         or established by the Company for or pursuant to the terms of any such
         plan, (ii) EGS Associates, L.P., a Delaware limited partnership, EGS
         Partners L.L.C., a Delaware limited liability company, Bev Partners,
         L.P., a Delaware limited partnership, Jonas Partners, L.P., a Delaware
         limited partnership, William Ehrman, Frederic Greenberg, Frederick
         Ketcher, Jonas Gerstl, James McLaren or

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         William Lautman, unless such Persons shall be the Beneficial Owners,
         individually or in the aggregate, of thirty percent (30%) or more of
         the shares of Common Stock then outstanding, PROVIDED, HOWEVER, that
         such percentage shall be reduced to twenty percent (20%) upon the
         earlier to occur of (x) the completion of the merger of RailTex, Inc.
         with and into a wholly-owned subsidiary of the Company and (y) April
         30, 2000, (iii) Barclays Bank PLC and the lenders named in that certain
         Senior Secured Loan Facility and Guaranty Agreement (the "Facility")
         dated as of April 30, 1999 among Freight Victoria, the Company,
         RailAmerica Australia Pty Ltd., Barclays Bank PLC and the lenders named
         therein (such lenders collectively with Barclays Bank PLC to be
         referred to hereinafter as the "Lenders"), but only with respect to (A)
         warrants (the "Warrants") to purchase shares of Common Stock issued by
         the Company to the Lenders pursuant to the Facility and pursuant to
         that certain Warrant Agreement dated as of April 30, 1999 between the
         Company and the Lenders and (B) the shares of Common Stock issuable
         upon exercise of the Warrants, it being understood that all other
         shares of Common Stock acquired by the Lenders independent of (A) or
         (B) above shall be considered for purposes of determining Acquiring
         Person status of Lenders; or (iv) any Person who or which, together
         with all Affiliates and Associates of such Person, would be an
         Acquiring Person solely by reason of a reduction in the number of
         issued and outstanding shares of Common Stock of the Company pursuant
         to a transaction or series of related transactions approved by a
         majority of the Independent Directors, if any, then in office and
         approved by a Supermajority Vote; provided, further, however, that in
         the event that such Person described in the foregoing clause (iv) does
         not become an Acquiring Person by reason of the foregoing clause (iv),
         such Person shall nonetheless become an Acquiring Person in the event
         such Person thereafter acquires Beneficial Ownership of an additional
         one percent (1%) of the Common Stock of the Company, unless such
         additional Common Stock ownership results solely from a subsequent
         reduction in the number of issued and outstanding shares of Common
         Stock of the Company."

         2. Except as specifically amended hereby, the Rights Agreement is and
remains unmodified and in full force and effect and is hereby ratified and
confirmed.

         3. This Amendment shall be deemed a contract made under the laws of the
State of Delaware and for all purposes shall be governed by and construed in
accordance with the laws of such State applicable to contracts made and to be
performed entirely within such State.

         4. This Amendment may be executed in counterparts and both of such
counterparts shall for all purposes be deemed to be an original, and such
counterparts shall constitute but one and the same instrument.

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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed as of the date first above written.

                                     RAILAMERICA, INC.

                                     By: /s/ Gary O. Marino
                                        ---------------------------------------
                                     Name: Gary O. Marino
                                     Its:  Chairman of the Board, President and
                                           Chief Executive Officer

                                     AMERICAN STOCK TRANSFER & TRUST COMPANY

                                     By: /s/ Herbert J. Lemmer
                                        ---------------------------------------
                                     Name: Herbert J. Lemmer
                                     Its:  Vice President

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