<PAGE>

                                   EXHIBIT 4.2



<PAGE>

            FOURTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT

         This Fourth Amendment to Amended and Restated Credit Agreement (the
"AMENDMENT") dated as of November 5, 1999 among Atchison Casting Corporation
(the "BORROWER"), the Banks, and Harris Trust and Savings Bank, as Agent;

                              W I T N E S S E T H:

         WHEREAS, the Borrower, Guarantors, Banks and Harris Trust and Savings
Bank, as Agent, have heretofore executed and delivered an Amended and Restated
Credit Agreement dated as of April 3, 1998 (as amended through the Third
Amendment thereto dated August 20, 1999, the "CREDIT AGREEMENT"); and

         WHEREAS, the Borrower intends to incur at least $20,000,000 in
aggregate principal amount of Subordinated Debt; and

         WHEREAS, the Banks' and Agent are relying on the Borrower's desire to
incur such Subordinated Debt in amending Section 7.15(e) of the Credit
Agreement; and

         WHEREAS, the parties hereto desire to amend the Credit Agreement as
provided herein;

         NOW, THEREFORE, for good and valuable consideration the receipt and
sufficiency of which is hereby acknowledged, the parties hereto agree that the
Credit Agreement shall be and hereby is amended as follows:

          1. The definition of "DOMESTIC RATE MARGIN" appearing in Section
1.3(a) of the Credit Agreement is hereby amended in its entirety and as so
amended shall read as follows:

                      "DOMESTIC RATE MARGIN" means (A) 0% per annum for any
             Pricing Period for which Level I Status exists and (B) 0.25%
             per annum for any Pricing Period for which either Level II
             Status or Level III Status exists.

          2. The definition of "EUROCURRENCY MARGIN" appearing in Section 1.3(b)
of the Credit Agreement is hereby amended in its entirety and as so amended
shall read as follows:

                      "EUROCURRENCY MARGIN" means (A) 1.60% per annum for
             any Pricing Period for which Level I Status exists, (B) 1.85%
             per annum for any Pricing Period for which Level II Status
             exists, and (C) 2.10% per annum for any Pricing Period for
             which Level III Status exists.




<PAGE>

          3. Section 1.13(a)  of the Credit Agreement is hereby amended by
inserting  immediately prior to the "." at the end thereof the following:

                ; PROVIDED, HOWEVER, that the proceeds of the issuance of up
                to $20,000,000 of Subordinated Debt on or prior to January 31,
                2000 shall be applied as a mandatory repayment of principal of
                the Revolving Loans with any amounts of such Subordinated Debt
                in excess thereof to be applied as a mandatory repayment of
                principal of the Term Loans to be applied 50% in the order of
                maturity and 50% in the inverse order of maturity.

          4.    The definition of "FIXED  CHARGES"  appearing in  Section 4.1
of the Credit  Agreement is hereby amended in its entirety and as so amended
shall read as follows:

                        "FIXED CHARGES" means, as applied to any Person for
                any period, the sum of (a) Interest Expense of such Person for
                such period, PLUS (b) the aggregate amount of Current
                Maturities required to be made by the Borrower and its
                Subsidiaries PLUS (c) 15% of the aggregate principal amount of
                Revolving Loans outstanding on the last day of such period;
                PROVIDED THAT if the Borrower issues at least $20,000,000 in
                aggregate principal amount of Subordinated Debt on or prior to
                January 31, 2000 clause (c) shall only be effective from and
                after July 1, 2000; PROVIDED FURTHER that if the Borrower does
                not issue at least $20,000,000 in aggregate principal amount
                of Subordinated Debt on or prior to January 31, 2000 clause
                (c) above shall be effective for all calculations at all times
                after October 1, 1999.

          5.    Section 7.15(c) of the Credit Agreement is hereby amended in its
entirety and as so amended shall read as follows:

                           (c) RATIO OF CONSOLIDATED TOTAL DEBT TO TOTAL
                  CAPITALIZATION. The Borrower will not on any date permit
                  Consolidated Total Debt to exceed 55% of Total Capitalization.


                                     -2-

<PAGE>

          6.    Section 7.15(e) of the Credit Agreement is hereby amended in
its entirety and as so amended shall read as follows:

                         (e) FIXED CHARGE COVERAGE RATIO. (i) If the Borrower
                issues at least $20,000,000 in aggregate principal amount of
                Subordinated Debt on or prior to January 31, 2000, the
                Borrower will not, as of the last day of each fiscal quarter
                of the Borrower ending during each of the periods specified
                below permit the Fixed Charge Coverage Ratio to be less than :

<TABLE>
<CAPTION>

                FROM AND INCLUDING       TO AND         FIXED CHARGE COVERAGE
                                       INCLUDING     RATIO SHALL NOT BE LESS
                                                               THAN:
              <S>                  <C>                  <C>
                December 31, 1999    June 30, 2000             1.10
                   July 1, 2000        Thereafter              1.25


</TABLE>
                           (ii) If the Borrower does not issue at least
                  $20,000,000 in aggregate principal amount of Subordinated Debt
                  on or prior to January 31, 2000, the Borrower will not, as of
                  the last day of each fiscal quarter of the Borrower ending
                  during each of the periods specified below permit the Fixed
                  Charge Coverage Ratio to be less than :

<TABLE>
<CAPTION>

                      FROM AND INCLUDING       TO AND           FIXED CHARGE COVERAGE
                                              INCLUDING     RATIO SHALL NOT BE LESS THAN:
                    <S>                   <C>                  <C>
                      December 31, 1999    March 30, 2000              1.10
                        March 31, 2000     March 30, 2001              1.25
                        March 31, 2001       Thereafter                1.50

</TABLE>


          7.    Section 7.18(d) of the Credit Agreement is hereby amended in its
entirety and as so amended shall be as follows:

                         (d) the Borrower and its Subsidiaries may make and
                own Investments in any Subsidiary of the Borrower or, from and
                after May 1, 2000 make and own or enter into any agreement to
                make or own Investments, in any Person which simultaneously
                therewith becomes a Subsidiary provided that such Person is
                engaged primarily in the foundry business or in businesses
                reasonably related thereto and (A) at least 7 days before
                consummation of such acquisition, the Borrower delivers to the
                Agent a certificate of the Chief Financial Officer, Controller
                or Treasurer of the Borrower certifying that immediately upon
                and following the consummation of such acquisition, the
                Borrower, on a PRO FORMA basis (assuming such acquisition had
                been consummated on the first day of the most recently ended
                period of four fiscal quarters for which financial statements
                have been or are required to have


                                     -3-

<PAGE>

                been delivered pursuant to Section 7.6), the Borrower would
                have a Fixed Charge Coverage Ratio (which for purposes of
                this Section 7.18(d) Fixed Charges shall at all times be
                calculated including clause (c) of the definition of Fixed
                Charges) of at least 1.50 to 1.00 (which certificate shall
                set forth calculations supporting such statement) and (B)
                either (i) at the time of such acquisition and after giving
                effect thereto the Borrower's ratio of Consolidated Total
                Debt to Total Capitalization does not exceed 40% (the "40%
                THRESHOLD") or (ii) once the 40% Threshold has been exceeded
                in that fiscal year, the total aggregate principal amount
                expended for all acquisitions thereafter in such fiscal year
                does not exceed 25% of the Stockholder's Equity of the
                Borrower as of the last day of the immediately preceding
                fiscal year of the Borrower PLUS 25% of the net proceeds (net
                proceeds for such purposes to mean gross proceeds less
                reasonable underwriting discounts and commissions and other
                reasonable costs directly incurred and payable as a result
                thereof) received by the Borrower from the issuance of
                additional equity or Subordinated Debt during the fiscal year
                of the proposed acquisition; PROVIDED that the Borrower will
                not, and will not permit any of its Subsidiaries to, directly
                or indirectly (through a Subsidiary or otherwise) increase
                its Investment in Fonderie d'Autun, a French corporation,
                above the amount outstanding on August 20, 1999 without the
                consent of the Required Banks; and

        8.    If the Borrower (i) has not on or before December 15, 1999
              received written commitments in form and substance acceptable to
              the Required Banks from a lender or lenders acceptable to the
              Required Banks to advance not less than $20,000,000 in aggregate
              principal amount of Subordinated Debt to the Borrower or (ii)
              has not actually received at least $20,000,000 in aggregate
              principal amount of such Subordinated Debt on or before January
              31, 2000, then the Borrower shall within 60 days of December 15,
              1999 or January 31, 2000, as applicable, provide (a) prior,
              perfected and enforceable liens in all right title and interest
              of the Borrower and of each Subsidiary in all cash and cash
              equivalents, accounts, chattel paper, general intangibles,
              instruments, investment property, documents, inventory,
              equipment and real property of every kind and description
              whether now owned or hereafter acquired and all proceeds thereof
              (collectively, the "COLLATERAL"). The liens in the Collateral
              shall be granted to the Agent for the ratable account of the
              Banks and shall be valid and perfected first liens subject to
              such exceptions as the Required Banks may agree. The Borrower
              covenants and agrees that it shall and shall cause each
              Subsidiary to execute such documents and instruments as the
              Agent or the Required Banks shall from time to time request and
              do such acts and things as the Agent or the Required Banks may
              reasonably request in order to provide for or protect or perfect
              the lien of the Agent in the Collateral as required herein.


                                     -4-

<PAGE>

        9. The Borrower represents and warrants to each Bank and the Agent
that (a) each of the representations and warranties set forth in Section 5 of
the Credit Agreement is true and correct on and as of the date of this Amendment
as if made on and as of the date hereof and as if each reference therein to the
Credit Agreement referred to the Credit Agreement as amended hereby; (b) after
giving effect to this Amendment, no Default and no Event of Default has occurred
and is continuing; and (c) without limiting the effect of the foregoing, the
Borrower's execution, delivery and performance of this Amendment have been duly
authorized, and this Amendment has been executed and delivered by duly
authorized officers of the Borrower.

         10. This Amendment shall become effective upon satisfaction of the
following conditions precedent:

                   (i) the Borrower, the Required Banks, and the Agent shall
         have executed and delivered this Amendment and the Guarantors shall
         have executed the consent attached hereto; and

                  (ii) the Agent shall have an amendment fee in the amount
of $100,000 to be shared by the Banks PRO RATA based on their each such Bank's
Percentage.

         This Amendment may be executed in any number of counterparts and by
different parties hereto on separate counterpart signature pages, each of which
when so executed shall be an original but all of which shall constitute one and
the same instrument. Except as specifically amended and modified hereby, all of
the terms and conditions of the Credit Agreement and the other Credit Documents
shall remain unchanged and in full force and effect. All references to the
Credit Agreement in any document shall be deemed to be references to the Credit
Agreement as amended hereby. All capitalized terms used herein without
definition shall have the same meaning herein as they have in the Credit
Agreement. This Amendment shall be construed and governed by and in accordance
with the internal laws of the State of Illinois.


                                     -5-

<PAGE>

Dated as of the date first above written.


                                         ATCHISON CASTING CORPORATION


                                         By: /s/ Kevin T. McDermed
                                             ---------------------------------
                                         Title: V.P. & Treasurer
                                                ------------------------------



                                         HARRIS TRUST AND SAVINGS BANK, in its
                                           individual capacity as a Bank
                                           and as Agent


                                         By: /s/ Len E. Myer
                                             ---------------------------------
                                         Title: Vice President
                                                ------------------------------


                                         COMMERCE BANK, N.A.


                                         By: /s/ Dennis R. Block
                                             ---------------------------------
                                         Title: Senior Vice President
                                                ------------------------------


                                         MERCANTILE BANK


                                          By: /s/ Barry P. Sullivan
                                              ---------------------------------
                                          Title: Vice President
                                                 ------------------------------


                                           KEY BANK NATIONAL ASSOCIATION


                                           By: /s/ Daniel Lally
                                             ----------------------------------
                                           Title: Assistant Vice President
                                                -------------------------------


                                     -6-

<PAGE>

                                            COMERICA BANK


                                            By: /s/ Jeffrey Peck
                                               --------------------------------
                                            Title: Vice President
                                                 ------------------------------


                                            HIBERNIA NATIONAL BANK


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


                                            NATIONAL WESTMINSTER BANK PLC

                                            Nassau Branch


                                            By: /s/ C.A. Parsons
                                                --------------------------------
                                            Title: Corporate Director
                                                   -----------------------------

                                            New York Branch


                                            By: /s/ C.A. Parsons
                                                --------------------------------
                                            Title: Corporate Director
                                                   -----------------------------


                                            NORWEST BANK MINNESOTA, N.A.


                                            By: /s/ R. Duncan Sinclair
                                                --------------------------------
                                            Title: V.P.
                                                   -----------------------------


                                     -7-