Document:

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                                                                [EXECUTION COPY]

                                                                   Exhibit 10.76

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                ASSET BRIDGE EQUITY REGISTRATION RIGHTS AGREEMENT

                                      among

                                RAILAMERICA, INC.

                                       and

                          THE PURCHASERS PARTY HERETO.

                             -----------------------

                          Dated as of February 4, 2000

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                                TABLE OF CONTENTS

1. Definitions................................................................1
2. Securities Subject to this Agreement.......................................3
3. Piggyback Registration.....................................................3
4. Hold-Back Agreements.......................................................4
5. Registration Expenses......................................................5
6. Indemnification............................................................5
7. Rule 144...................................................................7
8. Miscellaneous..............................................................8

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                ASSET BRIDGE EQUITY REGISTRATION RIGHTS AGREEMENT

         This ASSET BRIDGE EQUITY REGISTRATION RIGHTS AGREEMENT, dated as of
February 4, 2000(as amended, supplemented, amended and restated or otherwise
modified from time to time, this "AGREEMENT"), is made and entered by and
between RAILAMERICA, INC., a Delaware corporation ("HOLDINGS"), and the Persons
parties hereto as "Purchasers" (collectively, the "PURCHASERS").

                                    RECITALS

         This Agreement is being delivered pursuant to the Asset Bridge
Securities Purchase Agreement, dated as of February 4, 2000 (as amended,
supplemented or otherwise modified, "ASSET BRIDGE SECURITIES PURCHASE
AGREEMENT"), by and among Palm Beach Rail Holding, Inc., a Delaware corporation
("INTERMEDIATE HOLDINGS"), Holdings, each Designated Restricted Subsidiary of
Intermediate Holdings that is a party thereto as a "Guarantor" (each such
Designated Restricted Subsidiary, together with Holdings, the "GUARANTORS") and
the Purchasers. In order to induce the Purchasers to enter into the Asset Bridge
Securities Purchase Agreement, Holdings has agreed to provide the registration
rights set forth in this Agreement. The execution of this Agreement is a
condition to the closing under the Asset Bridge Securities Purchase Agreement.

                                    AGREEMENT

         The parties agree as follows:

         1. DEFINITIONS.

         (a) CERTAIN TERMS. As used in this Agreement, the following capitalized
terms shall have the following meanings:

                  "ASSET BRIDGE WARRANT AGREEMENT" means the Asset Bridge
         Warrant Agreement, dated as of February 4, 2000, among Holdings and the
         Purchasers, as amended, supplemented or otherwise modified from time to
         time.

                  "INDEMNIFIED PARTIES" is defined in SECTION 6(A) hereof.

                  "INDEMNIFYING PARTY" is defined in SECTION 6(C) hereof.

                  "NASD" means the National Association of Securities Dealers,
         Inc.

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                  "PIGGYBACK REGISTRATION" is defined in SECTION 3(A) hereof.

                  "PROSPECTUS" means the prospectus included in any Registration
         Statement, as amended or supplemented by any prospectus supplement with
         respect to the terms of the offering of any portion of the Registrable
         Securities covered by such Registration Statement and by all other
         amendments and supplements to the prospectus, including post-effective
         amendments and all material incorporated by reference in such
         prospectus.

                  "REGISTRABLE SECURITIES" means the Registrable Warrants and
         the Registrable Warrant Shares; PROVIDED, that a security ceases to be
         a Registrable Security when it is no longer a Transfer Restricted
         Security.

                  "REGISTRABLE WARRANT SHARES" means all Warrant Shares issuable
         to the holders of Warrants upon exercise of such Warrants.

                  "REGISTRABLE WARRANTS" means all Warrants originally issued
         pursuant to the Asset Bridge Warrant Agreement.

                  "REGISTRATION EXPENSES" is defined in SECTION 5 hereof.

                  "REGISTRATION STATEMENT" means any registration statement of
         Holdings which covers any of the Registrable Securities pursuant to the
         provisions of this Agreement, including the Prospectus, amendments and
         supplements to such Registration Statement, including post-effective
         amendments, all exhibits and all material incorporated by reference in
         such Registration Statement.

                  "SECURITIES ACT" means the Securities Act of 1933, as amended.

                  "TRANSFER RESTRICTED SECURITY" means the Registrable
         Securities upon original issuance thereof; PROVIDED, that a Registrable
         Security is no longer a Transfer Restricted Security when such
         Registrable Security is sold to the public.

                  "UNDERWRITTEN REGISTRATION" and "UNDERWRITTEN OFFERING" mean a
         registration in which securities of Holdings are sold to an underwriter
         for reoffering to the public.

                  "WARRANT SHARES" means the shares of Common Stock or any
         security substituted for the Common Stock in an amount equal to 3.5% of
         the common equity of Holdings issuable to the holders of Warrants upon
         exercise of the Warrants.

                  "WARRANTS" means the Warrants issued pursuant to the Asset
         Bridge Warrant Agreement to purchase Common Stock or any security
         substituted for the Common Stock

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         in an amount equal to 3.5% of the common equity of Holdings in
         accordance with the Asset Bridge Warrant Agreement.

         (b) ASSET BRIDGE SECURITIES PURCHASE AGREEMENT DEFINITIONS. Unless
otherwise defined herein or the context otherwise requires, terms used in this
Agreement, including its preamble, have the meanings provided in the Asset
Bridge Securities Purchase Agreement.

         2. SECURITIES SUBJECT TO THIS AGREEMENT.

         (a) REGISTRABLE SECURITIES. The securities entitled to the benefits of
this Agreement are the Registrable Securities.

         (b) HOLDERS OF REGISTRABLE SECURITIES. A Person is deemed to be a
holder of Registrable Securities whenever such Person owns Registrable
Securities of record or has provided evidence reasonably satisfactory to
Holdings that such Person has the right to acquire such Registrable Securities,
whether or not such acquisition has actually been effected and disregarding any
legal restrictions upon the exercise of such right.

         3. PIGGYBACK REGISTRATION.

         (a) RIGHT TO PIGGYBACK. Subject to the last sentence of this CLAUSE
(A), whenever Holdings proposes to register any shares of Common Stock (or
securities exercisable or exchangeable for or convertible into, or options to
acquire, Common Stock) with the Commission under the Securities Act and the
registration form to be used may be used for the registration of the Registrable
Securities (a "PIGGYBACK REGISTRATION"), Holdings will give written notice to
the Purchasers, at least 10 days prior to the anticipated filing date, of its
intention to effect such a registration, which notice will specify the proposed
offering price, the kind and number of securities proposed to be registered, the
distribution arrangements and such other information that at the time would be
appropriate to include in such notice, and will, subject to CLAUSE (B) below,
include in such Piggyback Registration all Registrable Securities with respect
to which Holdings has received written requests for inclusion therein within 5
days after the effectiveness of Holding's notice; PROVIDED, that if the proceeds
of the offering are to be used by Holdings or Intermediate Holdings to redeem
all of the Asset Bridge Notes, Holdings will not be required to include any
Registrable Securities in such Piggyback Registration. Except as may otherwise
be provided in this Agreement, Registrable Securities with respect to which such
request for registration has been received will be registered by Holdings and
offered to the public in a Piggyback Registration pursuant to this Section 3 on
the terms and conditions at least as favorable as those applicable to the
registration of shares of Common Stock to be sold by Holdings and by any other
Person selling under such Piggyback Registration.

         (b) PRIORITY ON PIGGYBACK REGISTRATION. Holdings shall use all
reasonable efforts to cause the managing underwriter or underwriters of a
proposed Underwritten Offering to permit the

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Registrable Securities requested to be included in the registration statement
for such offering to be included on the same terms and conditions as any other
Common Stock to be offered pursuant to such registration statement by Holdings
or any other security holders included therein. Notwithstanding the foregoing,
if the managing underwriter or underwriters of such offering deliver a written
opinion to Holdings that either because of (i) the kind or combination of
securities which the holders of Registrable Securities, Holdings and any other
Persons intend to include in such offering or (ii) the size of the offering
which such holders, Holdings and such other Persons intend to make, are such
that the success of the offering would be materially and adversely affected by
inclusion of the Registrable Securities requested to be included, then (A) in
the event that the size of the offering is the basis of such managing
underwriter's opinion, the amount of securities to be offered for the accounts
of such holders shall be reduced pro rata (according to the Registrable
Securities proposed for registration) to the extent necessary to reduce the
total amount of securities to be included in such offering to the amount
recommended by such managing underwriter or underwriters; PROVIDED, that if
securities are being offered for the account of other Persons as well as
Holdings, then with respect to the Registrable Securities intended to be offered
by such holders, the proportion by which the amount of such class of securities
intended to be offered by such holders is reduced shall not exceed the
proportion by which the amount of such class of securities intended to be
offered by such other Persons is reduced; and (B) in the event that the kind (or
combination) of securities to be offered is the basis of such managing
underwriter's opinion, (x) the Registrable Securities to be included in such
offering shall be reduced as described in clause (A) above (subject to the
proviso in clause (A)) or (y) if the actions described in clause (x) would, in
the judgment of the managing underwriter or underwriters, be insufficient to
substantially eliminate the adverse effect that inclusion of the Registrable
Securities requested to be included would have on such offering, such
Registrable Securities will be excluded from such offering.

         (c) SELECTION OF UNDERWRITERS. If any Piggyback Registration is an
Underwritten Offering, Holdings will select a managing underwriter or
underwriters to administer the offering, which managing underwriter or
underwriters will be of nationally recognized standing.

         4. HOLD-BACK AGREEMENTS.

         (a) Each holder of Registrable Securities whose Registrable Securities
are covered by a Registration Statement filed pursuant to Section 3 hereof
agrees, if requested by the managing underwriters in an Underwritten Offering,
not to effect any public sale or distribution of securities of Holdings of the
same class or convertible into or exercisable for securities of the same class,
as the securities included in such Registration Statement, including a sale
pursuant to Rule 144 under the Securities Act (except as part of such
Underwritten Registration), during the 30-day period prior to, and during the
90-day period beginning on, the closing date of each Underwritten Offering made
pursuant to such Registration Statement, to the extent timely notified in
writing by Holdings or the managing underwriters; PROVIDED, HOWEVER, that each

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holder of Registrable Securities shall be subject to the hold-back restrictions
of this Section 4(a) only once during any 365-day period.

         (b) The foregoing provisions shall not apply to any holder of
Registrable Securities if such holder is prevented by applicable statute or
regulation from entering any such agreement; PROVIDED, HOWEVER, that any such
holder shall undertake, in its request to participate in any such Underwritten
Offering, not to effect any public sale or distribution of any Registrable
Securities held by such holder and covered by a Registration Statement
commencing on the date of sale of the Registrable Securities unless it has
provided 45 days prior written notice of such sale or distribution to the
underwriter or underwriters.

         5. REGISTRATION EXPENSES. All reasonable expenses incident to Holdings'
performance of or compliance with this Agreement, including, without limitation,
all (i) registration and filing fees, fees and expenses associated with filings
required to be made with the NASD (including, if applicable, the fees and
expenses of any "qualified independent underwriter" and its counsel as may be
required by the rules and regulations of the NASD), (ii) fees and expenses of
compliance with securities or blue sky laws (including fees and disbursements of
counsel for the underwriters in connection with blue sky qualifications of the
Registrable Securities and determination of their eligibility for investment
under the laws of such jurisdictions as the managing underwriters may reasonably
designate), (iii) printing expenses (including expenses of printing certificates
for the Registrable Securities in a form eligible for deposit with The
Depository Trust Company and of printing prospectuses), (iv) fees and
disbursements of counsel for Holdings and for the sellers of the Registrable
Securities, and customary out of pocket expenses and fees paid by issuers to the
extent provided for in an underwriting agreement (excluding discounts,
commissions or fees of underwriters, selling brokers, dealer managers or similar
securities industry professionals relating to the distribution of the
Registrable Securities, transfer taxes or legal expenses of any Person other
than Holdings, Intermediate Holdings and the selling holders), (v) the cost of
securities acts liability insurance if Holdings so desires and (vi) fees and
expenses of other Persons retained by Holdings (all such expenses being herein
called "REGISTRATION EXPENSES") will be borne by Holdings, regardless whether
the Registration Statement becomes effective. Each holder of Registrable
Securities will pay any fees or disbursements of counsel to such holder and all
underwriting discounts and commissions and transfer taxes, if any, and provide
other fees, costs and expenses of such holder (other than Registration Expenses)
relating to the sale or disposition of such holder's Registrable Securities.
Holdings, in any event, will pay Holdings' own internal expenses (including,
without limitation, all salaries and expenses of its officers and employees
performing legal or accounting duties), the expense of any annual audit, the
fees and expenses incurred in connection with the listing of the securities to
be registered on each securities exchange on which similar securities issued by
Holdings are then listed and the fees and expenses of any Person, including
special experts, retained by Holdings.

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         6. INDEMNIFICATION.

         (a) INDEMNIFICATION BY HOLDINGS. Holdings agrees to indemnify and hold
harmless, to the full extent permitted by law, each holder of Registrable
Securities, its officers, directors and employees and each Person who controls
such holder (within the meaning of the Securities Act) (the "INDEMNIFIED
PARTIES") against all losses, claims, damages, liabilities and expenses incurred
by such Indemnified Party in connection with any actual or threatened action
arising out of or based upon any untrue or alleged untrue statement of a
material fact contained in any Registration Statement, Prospectus or preliminary
Prospectus or any omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, except insofar as the same arise out of or are based upon any such
untrue statement or omission made in reliance on and in conformity with any
information furnished in writing to Holdings by such holder or its counsel
expressly for use therein; PROVIDED, that Holdings shall not be liable in any
such case to the extent that any such loss, claim, damage, liability or expense
arises out of or is based upon an untrue statement or alleged untrue statement
or omission or alleged omission in the Prospectus, if such untrue statement or
alleged untrue statement, omission or alleged omission is completely corrected
in an amendment or supplement to the Prospectus and the holder of Registrable
Securities thereafter fails to deliver such Prospectus as so amended or
supplemented prior to or concurrently with the sale of the Registrable
Securities to the Person asserting such loss, claim, damage, liability or
expense after Holdings has furnished such holder with a sufficient number of
copies of the same. Holdings shall also indemnify underwriters, their officers
and directors and each Person who controls such Persons (within the meaning of
the Securities Act) to the same extent as provided above with respect to the
indemnification of the Indemnified Parties, if requested.

         (b) INDEMNIFICATION BY HOLDER OF REGISTRABLE SECURITIES. In connection
with a Piggy Back Registration, each holder of Registrable Securities included
therein will furnish to Holdings in writing such information and affidavits as
Holdings reasonably requests for use in connection with any such Registration
Statement or Prospectus and agrees to indemnify and hold harmless, to the
fullest extent permitted by law, Holdings, its directors and officers and each
Person who controls Holdings (within the meaning of the Securities Act) against
any losses, claims damages, liabilities and expenses resulting from any untrue
statement of a material fact contained in any Registration Statement or
Prospectus or any omission of a material fact required to be stated in the
Registration Statement or Prospectus or preliminary Prospectus or necessary to
make the statements therein not misleading, to the extent, but only to the
extent, that such untrue statement or omission relates to a holder and is made
in reliance on and in conformity with any information or affidavit furnished in
writing by such holder to Holdings specifically for inclusion in such
Registration Statement or Prospectus. In no event shall the liability of any
selling holder of Registrable Securities hereunder be greater in amount than the
dollar amount of the proceeds received by such holder upon the sale of the
Registrable Securities giving rise to such indemnification obligation. Holdings
shall be entitled to receive indemnities from underwriters, selling brokers,
dealer managers and similar securities industry professionals participating in
the distribution of such Registrable Securities to the same extent as provided
above with respect to

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information or affidavit furnished in writing by such Persons specifically for
inclusion in any Prospectus or Registration Statement.

         (c) CONDUCT OF INDEMNIFICATION PROCEEDINGS. Any Person entitled to
indemnification hereunder will (i) give prompt notice to Holdings or the holder
of Registrable Securities, as the case may be (in either case, as applicable, an
"INDEMNIFYING PARTY") of any claim with respect to which such Person seeks
indemnification and (ii) permit such Indemnifying Party to assume the defense of
such claim with counsel reasonably satisfactory to such Person; PROVIDED,
HOWEVER, that any Person entitled to indemnification hereunder shall have the
right to employ separate counsel and to participate in the defense of such
claim, but the fees and expenses of such counsel shall be at the expense of such
Person unless (a) the Indemnifying Party has agreed to pay such fees or
expenses, (b) the Indemnifying Party has failed to assume the defense of such
claim or (c) in the reasonable judgment of any such Person, based upon advice of
its counsel, a conflict of interest may exist between such Person and the
Indemnifying Party with respect to such claims (in which case, if such Person
notifies the Indemnifying Party in writing that such Person elects to employ
separate counsel at the expense of the Indemnifying Party, the Indemnifying
Party shall not have the right to assume the defense of such claim on behalf of
such Person). If such defense is not assumed by the Indemnifying Party, the
Indemnifying Party will not be subject to any liability for any settlement made
without its consent (but such consent will not be unreasonably withheld). No
Indemnifying Party will be required to consent to the entry of any judgment or
enter into any settlement which does not include as an unconditional term
thereof the giving by the claimant or plaintiff to such Person entitled to
indemnification a release from all liability in respect to such claim or
litigation. If any Indemnifying Party who is not entitled to, or elects not to,
assume the defense of a claim will not be obligated to pay the fees and expenses
of more than one counsel for all Persons entitled to indemnification by such
Indemnifying Party with respect to such claim, unless in the reasonable judgment
of any such Person a conflict of interest may exist between such Person and any
other Person entitled to indemnification with respect to such claim, in which
event the Indemnifying Party shall be obligated to pay the fees and expenses of
such additional counsel or counsels, but only of one such additional counsel for
each group of similarly situated Persons in any one jurisdiction.

         (d) CONTRIBUTION. If for any reason the indemnification provided for in
preceding CLAUSES (A) and (B) is unavailable to any Person entitled to
indemnification hereunder or is insufficient to hold such Person harmless as
contemplated by the preceding CLAUSES (A) and (B), then the Indemnifying Party
shall contribute to the amount paid or payable by such Person as a result of
such loss, claim, damage or liability in such proportion as is appropriate to
reflect not only the relative benefits received by such Person and the
Indemnifying Party, but also the relative fault of such Person and the
Indemnifying Party, as well as any other relevant equitable considerations;
PROVIDED, that no holder of Registrable Securities shall be required to
contribute an amount greater than the dollar amount of the proceeds received by
such holder of Registrable Securities with respect to the sale of any
securities. No Person guilty of fraudulent

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misrepresentation (within the meaning of Section 11(f) of the Securities Act)
shall be entitled to contribution from any Person who was not guilty of such
fraudulent misrepresentation.

         7. RULE 144. Holdings covenants that it will file the reports required
to be filed by it under the Securities Act and the Exchange Act and the rules
and regulations adopted by the Commission thereunder (or, if it is not required
to file such reports, it will, upon the request of any holder of Registrable
Securities made after the Fixed Rate Sale Date, make publicly available other
information so long as necessary to permit sales pursuant to Rule 144 under the
Securities Act), and it will take such further action as any holder of
Registrable Securities may reasonably request, all to the extent required from
time to time to enable such holder to sell Registrable Securities without
registration under the Securities Act within the limitation of the exemptions
provided by (a) Rule 144 under the Securities Act, as such Rule may be amended
from time to time, or (b) any similar rule or regulation hereafter adopted by
the Commission. Upon the request of any holder of Registrable Securities,
Holdings will deliver to such holder a written statement as to whether it has
complied with such information and filing requirements.

         8. MISCELLANEOUS.

         (a) REMEDIES. Each holder of Registrable Securities, in addition to
being entitled to exercise all rights provided herein or granted by law,
including recovery of damages, in connection with the breach by Holdings of its
obligations to register the Registrable Securities will, to the fullest extent
permitted under applicable law, be entitled to specific performance of its
rights under this Agreement. Holdings agrees that monetary damages would not be
adequate compensation for any loss incurred by reason of a breach by it of the
provisions of this Agreement and agrees, to the extent permitted under
applicable law, to waive the defense in any action for specific performance that
a remedy at law would be adequate.

         (b) NO INCONSISTENT AGREEMENTS. Holdings will not on or after the date
of this Agreement enter into any agreement with respect to its securities which
is inconsistent with the rights granted to the holders of Registrable Securities
in this Agreement or otherwise conflicts with the provisions hereof. The rights
granted to the holders of Registrable Securities hereunder do not in any way
conflict with and are not inconsistent with the rights granted to the holders of
Holdings' securities under any other agreements. Holdings has not previously
entered into any inconsistent agreement with respect to its securities granting
any registration rights to any Person.

         (c) AMENDMENTS AND WAIVERS. The provisions of this Agreement, including
the provisions of this sentence, may not be amended, modified or supplemented,
and waivers or consents to departures from the provisions of this Agreement may
not be given unless Holdings has obtained the written consent of holders of at
least a majority of the outstanding Registrable Securities (excluding
Registrable Securities held by Holdings or any of its Subsidiaries).

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         (d) NOTICES. All notices and other communications provided for or
permitted hereunder shall be made in writing by hand-delivery, registered
first-class mail, facsimile or air courier guaranteeing overnight delivery:

                  (i) if to a holder of Registrable Securities, at the most
         current address given by such holder to Holdings in accordance with the
         provisions of this Section 8(d), which address initially is, with
         respect to the Purchasers, the address set forth next to the
         Purchasers' name on the signature pages of the Asset Bridge Securities
         Purchase Agreement; and

                  (ii) if to Holdings, initially to it at the address set forth
         in the Asset Bridge Securities Purchase Agreement and thereafter at
         such other address, notice of which is given in accordance with the
         provisions of this SECTION 8(D).

All such notices and communications shall be deemed to have been duly given: at
the time delivered by hand, if personally delivered; five business days after
being deposited in the mail, postage prepaid, if mailed; when answered back, if
delivered by facsimile; and on the next business day, if timely delivered to an
air courier guaranteeing overnight delivery.

         (e) SUCCESSORS AND ASSIGNS. This Agreement shall inure to the benefit
of and be binding upon the successors and assigns of each of the parties hereto,
including without limitation, and without the need for an express assignment,
subsequent holders of Registrable Securities.

         (f) COUNTERPARTS. This Agreement 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.

         (g) HEADINGS. The headings in this Agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

         (h) NEW YORK LAW; SUBMISSION TO JURISDICTION; WAIVER OF JURY TRIAL.
THIS AGREEMENT SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY THE LAWS OF
THE STATE OF NEW YORK. EACH PARTY HERETO HEREBY SUBMITS TO THE NONEXCLUSIVE
JURISDICTION OF THE UNITED STATES DISTRICT COURT FOR THE SOUTHERN DISTRICT OF
NEW YORK AND OF ANY NEW YORK STATE COURT SITTING IN NEW YORK CITY FOR PURPOSES
OF ALL LEGAL PROCEEDINGS ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE
TRANSACTIONS CONTEMPLATED HEREBY. EACH PARTY HERETO IRREVOCABLY WAIVES, TO THE
FULLEST EXTENT PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW OR HEREAFTER
HAVE TO THE LAYING OF THE VENUE OF ANY SUCH PROCEEDING BROUGHT IN SUCH A COURT
AND ANY CLAIM THAT ANY SUCH PROCEEDING BROUGHT

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IN SUCH A COURT HAS BEEN BROUGHT IN AN INCONVENIENT FORUM. EACH PARTY HERETO
IRREVOCABLY WAIVES ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING
ARISING OUT OF OR RELATING TO THIS AGREEMENT OR THE TRANSACTIONS CONTEMPLATED
HEREBY.

         (i) SEVERABILITY. In the event that any one or more of the provisions
contained herein, or the application thereof in any circumstance, is held
invalid, illegal or unenforceable in any jurisdiction, the validity, legality
and enforceability of any such provision in such jurisdiction in every other
respect and of the remaining provisions contained herein shall not be affected
or impaired thereby.

         (j) ENTIRE AGREEMENT. This Agreement is intended by the parties as a
final expression of their agreement with respect to the subject matter contained
herein and intended to be a complete and exclusive statement of the agreement
and understanding of the parties hereto in respect of the subject matter
contained herein. There are no restrictions, promises, warranties or
undertakings, other than those set forth or referred to herein with respect to
the registration rights granted by Holdings with respect to the Registrable
Securities. This Agreement supersedes all prior agreements and understandings
between the parties with respect to such subject matter.

                                      -10-

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         IN WITNESS WHEREOF, the parties have executed this Asset Bridge Equity
Registration Rights Agreement as of the date first written above.

                                           RAILAMERICA, INC.

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

                                           PURCHASERS:
                                           RAIL AMERICA HOLDINGS FUNDING,
                                           INC.

                                           By:   /s/ Eugene F. Martin
                                              ----------------------------------
                                                Name:  Eugene F. Martin
                                                Title:  Senior Vice President

                                      -11-<PAGE>   1
                                                                 Exhibit 10(r)

                      FIRST AMENDMENT TO CREDIT AGREEMENT

         THIS AMENDMENT TO CREDIT AGREEMENT dated as of September 30, 1999
("this Amendment") is entered into by RESPONSE ONCOLOGY, INC., a Tennessee
corporation ("Response"), RESPONSE ONCOLOGY MANAGEMENT OF SOUTH FLORIDA, INC., a
Tennessee corporation ("Management"), RESPONSE ONCOLOGY OF TAMARAC, INC., a
Florida corporation ("Tamarac") and RESPONSE ONCOLOGY OF FORT LAUDERDALE, INC.,
a Florida corporation ("Fort Lauderdale"; Response, Management, Tamarac and Fort
Lauderdale are sometimes together referred to as the "Borrowers"), AMSOUTH BANK,
an Alabama banking corporation ("AmSouth"), UNION PLANTERS BANK NATIONAL
ASSOCIATION, a national banking association ("UP"), and BANK OF AMERICA, N.A., a
national banking association and formerly known as NationsBank, N.A.
(collectively, the "Lenders"), and AMSOUTH BANK, an Alabama banking corporation,
as agent for the Lenders (the "Agent").

                                    Recitals

         A. The Borrowers, the Agent and the Lenders are parties to that certain
Credit Agreement dated as of June 10, 1999 (the "Agreement") pursuant to which
the Lenders have made available to the Borrowers (i) a revolving credit facility
in an aggregate principal amount outstanding not to exceed $7,000,000, and (ii)
a term loan facility in the principal amount of $35,000,000.

         B. The Borrowers have applied to the Lenders for modifications to
certain provisions of the Agreement.

         C. The Lenders are willing to make such modification as requested only
if, among other things, the Borrowers enter into this Amendment.

                                   Agreement

         NOW, THEREFORE, in consideration of the foregoing Recitals, the
Borrowers, the Lenders and the Agent hereby agree as follows:

         1. Capitalized terms used in this Amendment and not otherwise
defined herein have the respective meanings attributed thereto in the Agreement.

         2. The definition of "Applicable Commitment Fee." "Applicable LIBO Rate
Margin," and "Applicable Prime Rate Margin" shall be amended to read, in its
entirety, as follows:

                  "Applicable Commitment Fee," "Applicable LIBO Rate Margin,"
         and "Applicable Prime Rate Margin" mean, with respect to any Loan and
         the commitment

                                       1
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         fee respecting the Revolving Credit Loan, during any Effective Period,
         the percentage rate per annum set forth below:

          Prime Rate             LIBOR         Commitment Fee
            Margin               Margin        in Basis Points

            1.00%                 3.25%           62.5 bps

         3. The reference in Section 2.1 of the Agreement to "$7,000,000" shall
be amended to read "$6,000,000".

         4. The repayment grid set forth in Section 2.10 of the Agreement is
hereby amended to read, in its entirety, as follows:

          Date                               Quarterly Payment
          ----                               -----------------

     July 1, 1999                                     1,250,000
     October 1, 1999                                  1,250,000
     November 15, 1999                                  416,667
     December 1, 1999                                   416,667
     January 1, 2000                                    416,667
     April 1, 2000                                    1,250,000
     July 1, 2000                                     1,500,000
     October 1, 2000                                  1,500,000
     January 1, 2001                                  1,500,000
     April 1, 2001                                    1,500,000
     July 1, 2001                                     1,500,000
     October 1, 2001                                  1,500,000
     January 1, 2002                                  1,500,000
     April 1, 2002                                    1,500,000
     June 10, 2002                          Balance Due in Full

         5. The "Revolving Credit Commitment" for AmSouth and UP is hereby
amended as set forth on the attached signature page for such financial
institution.

         6. Section 6.1.7 of the Agreement is hereby amended to read, in its
entirety, as follows:

                  6.1.7 Purchase Money Debt. Purchase Money Debt, including
         Assumed Debt, existing on the date of this Amendment and set forth on
         Schedule 6.1.7 attached hereto.

                                       2
<PAGE>   3
         7. Section 6.11 of the Agreement is hereby amended to read, in its
entirety, as follows:

                  6.11 Advances. No Consolidated Entities shall extend any loans
         to any other Persons except for the loans (including Provider Loans)
         existing on the date of this Agreement and set forth on Schedule 6.11
         attached hereto.

         8. Section 7.2 of the Agreement is hereby amended to read, in its
entirety, as follows:

                  7.2 Total Funded Debt to Consolidated EBITDA. Borrower shall
         maintain a ratio of Total Funded Debt divided by Consolidated EBITDA,
         measured as of the end of each fiscal quarter for the previous four
         consecutive fiscal quarters, of no greater than 4.0:1.0 through the
         fiscal quarter ending September 30, 1999, of no greater than 4.25:1.0
         through the fiscal quarter ended December 31, 1999 and of no greater
         than 3.00:1.00 thereafter.

         9. Section 7.5 of the Agreement is hereby amended to read, in its
entirety, as follows:

                  7.5 Capital Expenditures. Borrower shall not incur Capital
         Expenditures for any fiscal year without the prior written consent of
         the Lenders, other than those Capital Expenditures listed on Exhibit A.

         10. The Lenders agree to waive (a) the failure by the Borrowers to
comply with the financial covenants set forth in Sections 7.3 and 7.4 for the
fiscal quarters ending September 30, 1999 and December 31, 1999 and (b) any and
all Defaults, Events of Default and remedies the Lenders and Agent may have that
arise from Borrowers' failure to comply with the above-referenced financial
covenants.

         11. The following Section 7.7 is hereby added to the Agreement and
shall read as follows:

                  7.7 Minimum EBITDA. EBITDA for the Borrower shall not be less
         than (a) $1,464,000 for the three months ending September 30, 1999, (b)
         $500,000 for the months of October, November and December, 1999,
         provided, however, any excess EBITDA above the minimum set forth in
         this subparagraph (b) may be carried forward to the next succeeding
         month for October, November and December so long as EBITDA for the
         three months ending December 31, 1999 exceeds $1,500,000, and (c)
         $600,000 for the months of January, February and March, 2000; provided,
         however, any excess EBITDA above the minimum set forth in this
         subparagraph (c) may be carried forward to the next succeeding month
         for January, February and March so long as EBITDA for the three months
         ending March 31, 2000 exceeds $1,800,000.

         12. Section 8.1.1 of the Agreement is hereby amended to read, in its
entirety, as follows:

                                       3
<PAGE>   4

                  8.1.1 Payments. Borrowers' failure to make payment of any
         amount of the Obligations.

         13. Section 8.1.5 of the Agreement is hereby amended to read, in its
entirety, as follows:

                  8.1.5 Reporting Requirements. The failure of Borrowers or any
         other party to timely perform any covenant in the Credit Documents
         requiring the furnishing of notices, financing reports or other
         information to Lenders; and provided, however, that during any period
         of time that a report is delinquent, Agent may at its option increase
         the Pricing Values to their highest levels permitted under this
         Agreement.

         14. As consideration for the Lenders' agreement to make the
modification set forth in this Amendment, the Borrowers shall pay a fee in the
amount of $19,250 to the Agent for the account of each of the Lenders. This fee
shall be due and payable upon the execution of this Amendment and shall be fully
earned and non-refundable.

         15. Notwithstanding the execution of this Amendment, all of the
indebtedness evidenced by each of the Notes shall remain in full force and
effect, as modified hereby, and nothing contained in this Amendment shall be
construed to constitute a novation of the indebtedness evidenced by any of the
Notes or to release, satisfy, discharge, terminate or otherwise affect or impair
in any manner whatsoever (a) the validity or enforceability of the indebtedness
evidenced by any of the Notes; (b) the liens, security interests, assignments
and conveyances affected by the Agreement or the Loan Documents, or the priority
thereof; (c) the liability of any maker, endorser, surety, guarantor or other
person that may now or hereafter be liable under or on account of any of the
Notes or the Agreement or the Loan Documents; or (d) any other security or
instrument now or hereafter held by the Agent or the Lenders as security for or
as evidence of any of the above-described indebtedness.

         16. All references in the Loan Documents to "Credit Agreement" shall
refer to the Agreement as amended by this Amendment, and as the Agreement may be
further amended from time to time.

         17. The Borrowers hereby certify that the organizational documents of
the Borrowers have not been amended since June 10, 1999.

         18. The Borrowers hereby represent and warrant to the Agent and the
Lenders that all representations and warranties contained in the Agreement are
true and correct as of the date hereof, and the Borrowers hereby certify that no
Event of Default nor any event that, upon notice or lapse of time or both, would
constitute an Event of Default, has occurred and is continuing.

          19. Except as hereby amended, the Agreement shall remain in full
force and effect as written. This Amendment may be executed in one or more
counterparts, each of which shall be deemed an original, and all of which when
taken together shall constitute one and the same instrument. The covenants and
agreements contained in this Amendment shall apply to and inure

                                       4
<PAGE>   5

to the benefit of and be binding upon the parties hereto and their respective
successors and permitted assigns.

         20. Nothing contained herein shall be construed as a waiver,
acknowledgment or consent to any breach of or Event of Default under the
Agreement and the Loan Documents not specifically mentioned herein.

         21. This Amendment shall be governed by the laws of the State of
Alabama.

                  [Remainder of this page intentionally blank]

                                       5

<PAGE>   6

         IN WITNESS WHEREOF, each of the Borrowers, the Lenders and the Agent
has caused this Amendment to be executed and delivered by its duly authorized
corporate officer as of the day and year first above written.

                                        RESPONSE ONCOLOGY, INC.

                                        By: /s/
                                            -----------------------------------
                                            Its: CFO

                                        RESPONSE ONCOLOGY MANAGEMENT
                                        OF SOUTH FLORIDA, INC.

                                        By: /s/
                                            -----------------------------------
                                            Its: CFO

                                        RESPONSE ONCOLOGY OF TAMARAC, INC.

                                        By: /s/
                                            -----------------------------------
                                            Its: CFO

                                        RESPONSE ONCOLOGY OF FORT LAUDERDALE,
                                        INC.

                                        By: /s/
                                            -----------------------------------
                                            Its: CFO

                                      6

<PAGE>   7

                                        AMSOUTH BANK

                                        By: /s/
                                            -----------------------------------
                                            Its: Vice President

                                        Revolving Credit Commitment: $3,692,400

                                        UNION PLANTERS BANK NATIONAL
                                        ASSOCIATION

                                        By: /s/
                                            -----------------------------------
                                            Its: Vice President

                                        Revolving Credit Commitment: $2,307,600

                                        BANK OF AMERICA, N.A. (formerly known as
                                        NationsBank, N.A.)

                                        By: /s/
                                            -----------------------------------
                                            Its: Senior Vice President

                                        AMSOUTH BANK, as Agent

                                        By: /s/
                                            -----------------------------------
                                            Its: Vice President

                                        7

<PAGE>   8
RESPONSE ONCOLOGY, INC.
CAPITAL EXPENDITURES
Through January 31, 2000

                                   Exhibit A

<TABLE>
<CAPTION>
                LOCATION                                     DESCRIPTION                                   AMOUNT
                --------                                     -----------                                  --------
<S>                                                          <C>                                          <C>
Oncology & Hematology Consultants, PLLC                      Chemistry Analyzer                           $ 57,000

Hematology Oncology Associates of the Treasure Coast PA      Server                                          4,000

J. Paonessa, M.D., PA                                        Satellite Office Build Out                     20,350

J. Paonessa, M.D., PA                                        Server/PC's/Cabling                            22,233

J. Paonessa, M.D., PA                                        Medical Manager Software/Installation          22,935

Oncology & Hematology Group of South Florida, PA             AVI Pumps (14 Refurbished)                      4,550

Oncology & Hematology Group of South Florida, PA             Computers(3)                                    3,000

IMPACT Center of Hollywood                                   CBC Analyzer                                   18,500

IMPACT Center of Lehigh Valley                               iMac/Router                                     2,500

IMPACT Center of Youngstown                                  iMac/Router                                     2,500

IMPACT Center of St. Joseph                                  iMac/Router                                     2,500

IMPACT Center of Colorado Springs                            iMac/Router                                     2,500

IMPACT Center of Pensacola                                   iMac/Router                                     2,500

IMPACT Center of Albuquerque                                 iMac/Router                                     2,500

Tampa Pharmacy                                               iMac/Router                                     2,500

Bayonne Hospital                                             iMac/Router                                     2,500

Mercy Hospital Cancer Center                                 iMac/Router                                     2,500

North Shore Hematology Oncology                              iMac/Router                                     2,500

IMPACT Center of Washington                                  iMac/Router                                     2,500

IMPACT Center of Little Rock                                 iMac/Router                                     2,500

IMPACT Center of Nashville                                   iMac                                            1,000

Corporate                                                    Notebook/Docking Station                        3,300

Corporate                                                    PC's(3)                                         3,000
                                                                                                          --------

     Total                                                                                                $189,868
                                                                                                          ========

</TABLE>

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