EXHIBIT 5.1


                       [LETTERHEAD OF JENKENS & GILCHRIST]


                                   May 3, 1999

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

         Re:      Trinity Industries, Inc. - Registration Statement on Form S-8

Gentlemen:

         We are counsel to Trinity Industries, Inc., a Delaware corporation (the
"Company"),  and have acted as such in connection  with the  preparation  of the
Registration  Statement on Form S-8 (the  "Registration  Statement") to be filed
with the Securities and Exchange  Commission on or about May 3, 1999,  under the
Securities Act of 1933, as amended (the "Securities Act"), relating to 2,000,000
shares (the  "Shares") of the $1.00 par value common stock (the "Common  Stock")
of the Company  that have been or may be issued by the  Company  pursuant to the
Trinity  Industries,  Inc.  1998 Stock  Option and  Incentive  Plan  between the
Company and the signatories thereto (the "Plan").

         You have  requested an opinion with respect to certain legal aspects of
the proposed offering. In connection therewith, we have examined and relied upon
the original,  or copies identified to our satisfaction,  of (1) the Certificate
of Incorporation  of the Company and the Bylaws of the Company;  (2) minutes and
records  of  the  corporate  proceedings  of the  Company  with  respect  to the
establishment  of the Plan,  the  reservation  of 2,000,000  Shares to be issued
pursuant  to the Plan and to  which  the  Registration  Statement  relates,  the
issuance of the shares of Common Stock pursuant to the Plan and related matters;
(3) the Registration Statement and exhibits thereto, including the Plan; and (4)
such  other  documents  and  instruments  as we have  deemed  necessary  for the
expression of opinions herein contained.  In making the foregoing  examinations,
we have assumed the  genuineness of all signatures and the  authenticity  of all
documents submitted to us as originals, and the conformity to original documents
of all  documents  submitted  to us as certified or  photostatic  copies.  As to
various  questions of fact material to this  opinion,  and as to the content and
form  of  the  Certificate  of  Incorporation,  the  Bylaws,  minutes,  records,
resolutions and other documents or writings of the Company,  we have relied,  to
the extent deemed reasonably  appropriate,  upon representations or certificates
of  officers  or  directors  of the  Company  and upon  documents,  records  and
instruments  furnished  to us by  the  Company,  without  independent  check  or
verification of their accuracy.

         Based  upon our  examination,  consideration  of, and  reliance  on the
documents and other matters described above, and assuming that:








Trinity Industries, Inc.
May 3, 1999
Page 2



         (1) the Shares to be sold and issued in the future  will be duly issued
and sold in accordance with the terms of the Plan;

         (2) the Company maintains an adequate number of authorized but unissued
shares  and/or  treasury  shares  available  for  issuance to those  persons who
purchase Shares pursuant to the Plan; and

         (3) the  consideration  for the Shares  issued  pursuant to the Plan is
actually  received  by the  Company as  provided in the Plan and exceeds the par
value of such shares;

then, we are of the opinion that,  the Shares issued or sold in accordance  with
the  terms  of the  Plan  will  be duly  and  validly  issued,  fully  paid  and
nonassessable.

         We hereby  consent to the  filing of this  opinion as an exhibit to the
Registration Statement and to references to us included in or made a part of the
Registration  Statement.  In giving this  consent,  we do not admit that we come
within the category of persons whose consent is required  under Section 7 of the
Securities  Act or the Rules and  Regulations  of the  Securities  and  Exchange
Commission thereunder.

                                                 Sincerely,

                                                 Jenkens & Gilchrist,
                                                 A Professional Corporation


                                        By:      /s/ W. Alan Kailer
                                                 -------------------------------
                                                 W. Alan Kailer,
                                                 Authorized Signatory