[The remainder of this page is intentionally left blank.]

Exhibit 10.4

February 8, 2013

The Greenbrier Companies, Inc.

One Centerpointe Drive, Suite 200

Lake Oswego, OR 97035

Ladies and Gentlemen:

Reference is made to the Credit Agreement. Capitalized terms used herein and not otherwise defined herein shall have the meanings assigned thereto in the Credit Agreement.

The parties hereto agree that:

(i) The following definitions in Section 1.01 of the Credit Agreement are hereby amended to read as follows:

“Disposition” or “Dispose” means the sale, transfer, license, lease or other disposition (including any sale and leaseback transaction) of any property by any Person, including any sale, assignment, transfer or other disposal, with or without recourse, of any notes or accounts receivable or any rights and claims associated therewith. For purposes of clarification, the use of cash or money in the ordinary course of business or in a manner not otherwise expressly prohibited by the terms of this Agreement, in each case, shall not constitute a “Disposition” or to “Dispose” under this Agreement.

“Eurocurrency Rate” means,

(a) for any Interest Period with respect to a Eurocurrency Rate Loan, (i) the rate per annum equal to the British Bankers Association LIBOR Rate or the successor thereto if the British Bankers Association is no longer making a LIBOR rate available (“LIBOR”), as published by Reuters (or such other commercially available source providing quotations of LIBOR as may be designated by the Administrative Agent from time to time) at approximately 11:00 a.m., London time, two Business Days prior to the commencement of such Interest Period, for deposits in the relevant currency (for delivery on the first day of such Interest Period) with a term equivalent to such Interest Period or (ii) if such published rate is not available at such time for any reason, the rate determined by the Administrative Agent to be the rate at which deposits in the relevant currency for delivery on the first day of such Interest Period in Same Day Funds in the approximate amount of the Eurocurrency Rate Loan being made, continued or converted and with a term equivalent to such Interest Period would be offered by Bank of America’s London Branch (or other Bank of America branch or Affiliate) to major banks in the London or other offshore interbank market for such currency at their request at approximately 11:00 a.m. (London time) two Business Days prior to the commencement of such Interest Period; and

(b) for any interest calculation with respect to a Base Rate Loan on any date, the rate per annum equal to (i) LIBOR at approximately 11:00 a.m. London time two Business Days prior

to such date for Dollar deposits being delivered in the London interbank market for a term of one month commencing that day or (ii) if such published rate is not available at such time for any reason, the rate per annum determined by the Administrative Agent to be the rate at which deposits in Dollars for delivery on the date of determination in same day funds in the approximate amount of the Base Rate Loan being made or maintained and with a term equal to one month would be offered by Bank of America’s London Branch to major banks in the London interbank Eurodollar market at their request at the date and time of determination.

“FATCA” means Sections 1471 through 1474 of the Code, as of the Closing Date (or any amended or successor version that is substantively comparable and not materially more onerous to comply with) and any current or future regulations or official interpretations thereof and any agreements entered into pursuant to Section 1471(b)(1) of the Code.

(ii) Section 2.04(a) of the Credit Agreement is hereby amended to read as follows:

(a) The Swing Line. Subject to the terms and conditions set forth herein, the Swing Line Lender shall, in reliance upon the agreements of the other Lenders set forth in this Section 2.04, make loans to the Borrower in Dollars (each a “Swing Line Loan”) from time to time on any Business Day during the Availability Period in an aggregate amount not to exceed at any time outstanding the amount of the Swing Line Sublimit, notwithstanding the fact that such Swing Line Loans, when aggregated with the Applicable Percentage of the Outstanding Amount of Committed Loans and L/C Obligations of the Lender acting as Swing Line Lender, may exceed the amount of such Lender’s Commitment; provided, however, that (i) after giving effect to any Swing Line Loan, (A) the Total Outstandings shall not exceed the Revolver Ceiling, and (B) the aggregate Outstanding Amount of the Committed Loans of any Lender, plus such Lender’s Applicable Percentage of the Outstanding Amount of all L/C Obligations, plus such Lender’s Applicable Percentage of the Outstanding Amount of all Swing Line Loans shall not exceed such Lender’s Commitment, (ii) the Borrower shall not use the proceeds of any Swing Line Loan to refinance any outstanding Swing Line Loan and (iii) the Swing Line Lender shall not be under any obligation to make any Swing Line Loan if it shall determine (which determination shall be conclusive and binding absent manifest error) that it has, or by such Credit Extension may have, Fronting Exposure. Within the foregoing limits, and subject to the other terms and conditions hereof, the Borrower may borrow under this Section 2.04, prepay under Section 2.06, and reborrow under this Section 2.04. Immediately upon the making of a Swing Line Loan, each Lender shall be deemed to, and hereby irrevocably and unconditionally agrees to, purchase from the Swing Line Lender a risk participation in such Swing Line Loan in an amount equal to the product of such Lender’s Applicable Percentage times the amount of such Swing Line Loan.

(iii) Section 3.01 of the Credit Agreement is hereby amended to add a new clause (g) at the end of Section 3.01, immediately following clause (f), to read as follows:

(g) Notwithstanding anything to the contrary contained herein, if a payment made to a Lender under any Loan Document would be subject to U.S. federal withholding Tax imposed by FATCA if such Lender were to fail to comply with the applicable reporting requirements of FATCA (including those contained in Section 1471(b) or 1472(b) of the Code, as applicable), such Lender shall deliver to the Borrower and the Administrative Agent at the time or times prescribed by law and at such time or times reasonably requested by the Borrower or the Administrative Agent such documentation prescribed by applicable law (including as prescribed by Section 1471(b)(3)(C)(i) of the Code) and such additional documentation reasonably

requested by the Borrower or the Administrative Agent as may be necessary for the Borrower and the Administrative Agent to comply with their obligations under FATCA and to determine that such Lender has complied with such Lender’s obligations under FATCA or to determine the amount to deduct and withhold from such payment. Solely for purposes of this Section 3.01(g), “FATCA” shall include any amendments made to FATCA after the Closing Date.

(iv) Section 7.05(h) of the Credit Agreement is hereby amended to read as follows:

(h) sales or other Dispositions of assets having a fair market value (as determined by the Borrower in its reasonable discretion) of less than $50,000,000 in the aggregate during the term of this Agreement;

(v) Schedule 2 to Exhibit D to the Credit Agreement is hereby deleted and replaced with Schedule 2 attached hereto.

This letter agreement is a Loan Document. All references in the Credit Agreement and the other Loan Documents to the “Credit Agreement” shall be deemed to refer to the Credit Agreement as amended hereby.

Except as modified hereby, all of the terms and provisions of the Credit Agreement and the other Loan Documents shall remain in full force and effect.

This letter agreement shall become effective upon the execution hereof by the Loan Parties, the Required Lenders and the Administrative Agent.

This letter agreement may be executed in one or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. Delivery of executed counterparts of this Agreement by telecopy or pdf shall be effective as an original.

[The remainder of this page is intentionally left blank.]

This letter agreement shall be governed by and construed in accordance with the laws of the State of New York.

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

ACCEPTED AND AGREED AS OF THE DATE FIRST ABOVE WRITTEN:

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

ACCEPTED AND AGREED AS OF THE DATE FIRST ABOVE WRITTEN:

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

THE GREENBRIER COMPANIES, INC.

SECOND AMENDMENT

For the Quarter/Year ended                     (“Statement Date”)

SCHEDULE 2

to the Compliance Certificate

($ in 000’s)

minimum Consolidated Adjusted Interest Coverage Ratio permitted for Subject Period: see Section 7.11(a) of the Credit Agreement

maximum capital expenditures permitted in any fiscal year of the Borrower and its Subsidiaries: $50,000,000