The Greenbrier Companies, Inc. (GBX) 10-Q 2012 Q2 Quarterly report

Exhibit 32.2

THE GREENBRIER COMPANIES, INC.

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the quarterly report of The Greenbrier Companies, Inc. (the “Company”) on Form 10-Q for the quarterly period ended February 29, 2012 as filed with the Securities and Exchange Commission on the date therein specified (the “Report”), I, Mark J. Rittenbaum, Executive Vice President and Chief Financial Officer of the Company, certify pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Date: April 9, 2012

/s/ Mark J. Rittenbaum

Mark J. Rittenbaum

Executive Vice President and

Chief Financial Officer