Exhibit 10.3

SUPPLEMENT TO SUBSIDIARY GUARANTY
Reference is hereby made to the Amended and Restated Guaranty (as the same may
be amended, restated, supplemented or otherwise modified from time to time, the
“Guaranty”) made as of November 1, 2018, by each of the Material Domestic
Subsidiaries of Trinity Industries, Inc., a Delaware corporation (the
“Borrower”) listed on the signature pages thereto (each, an “Initial Guarantor”
and together with any additional Subsidiaries of the Borrower, which become
parties thereto and together with the undersigned, the “Guarantors”) in favor of
the Administrative Agent, for the ratable benefit of the Holders of Guaranteed
Obligations, under the Credit Agreement. Capitalized terms used herein and not
defined herein shall have the meanings given to them in the Guaranty. By its
execution below, the undersigned TRINITYRAIL MAINTENANCE SERVICES, INC., a
Delaware corporation (the “New Guarantor”), agrees to become, and does hereby
become, a Guarantor under the Guaranty and agrees to be bound by such Guaranty
as if originally a party thereto. By its execution below, the undersigned
represents and warrants as to itself that all of the representations and
warranties contained in Section 2 of the Guaranty are true and correct in all
respects as of the date hereof.
IN WITNESS WHEREOF, New Guarantor has executed and delivered this Annex I
counterpart to the Guaranty as of this 22nd day of April, 2019.
TRINITYRAIL MAINTENANCE SERVICES, INC.

By:     /s/ C. Lance Davis        
Its:    Vice President and Treasurer