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                                                                       Exhibit 5





                                                    (214) 740-8522





                                 July 15, 1996



Trinity Industries, Inc.
2525 Stemmons Freeway
Dallas, Texas 75207

Gentlemen:

         We have acted as counsel for Trinity Industries, Inc. (the "Company")
in connection with the preparation and filing with the Securities and Exchange
Commission of a Registration Statement on Form S-4 under the Securities Act of
1933, as amended (the "Registration Statement"), relating to 1,338,804 shares
of the Company's Common Stock, par value $1.00 per share (the "Shares"), that
may be issued by the Company to the shareholders of Transcisco Industries,
Inc., a Delaware corporation ("Transcisco"), in connection with the merger (the
"Merger") of Trinity Y, Inc., a Delaware corporation ("Trinity Y"), with and
into Transcisco.

         In this connection, we have examined the following documents:

         (i)     Copy, certified by the Secretary of State of the State of
                 Delaware, of the Certificate of Incorporation of the Company,
                 as amended;

         (ii)    Copy of the By-laws and Minutes of the meetings of the
                 directors and stockholders from the inception of the Company
                 to the date hereof;

         (iii)   The Merger Agreement, dated June 17, 1996, by and between the
                 Company, Trinity Y and Transcisco (the "Merger Agreement");
                 and

         (iv)    The Registration Statement and all Exhibits thereto.
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Trinity Industries, Inc.
July 15, 1996
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         We have also examined such other documents as we have deemed necessary
to the expression of the opinions contained herein.

         Based upon the foregoing, we are of the opinion that:

         (1)     The Company has been duly organized and is in good standing
                 under the laws of the State of Delaware;

         (2)     The issuance by the Company pursuant to the Merger Agreement
                 of the Company's Shares has been duly and validly authorized
                 by necessary corporate action; and

         (3)     The Company's Shares, upon delivery of such Shares after the
                 Merger duly executed by the Company and countersigned by its
                 Transfer Agent, will have been validly issued and will be
                 fully paid and non- assessable.

         We hereby consent to the use of our name in the Registration Statement
and in the related Prospectus and to the filing of a copy of this opinion as
Exhibit 5 to the Registration Statement.

                                        Very truly yours,

                                        LOCKE PURNELL RAIN HARRELL
                                        (A Professional Corporation)



                                         By: /s/ Charles C. Reeder
                                             -----------------------------------
                                             Charles C. Reeder


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