EXHIBIT 5.1




April 5, 2002



Trinity Industries, Inc.
2525 Stemmons Freeway
Dallas, Texas 75207-2401

Re:      Registration Statement on Form S-8 of 1,800,000 shares of Common Stock,
         par value $1.00 per share, of Trinity Industries, Inc.

Gentlemen:

We have acted as counsel to Trinity Industries, Inc., a Delaware corporation
(the "COMPANY"), in connection with the preparation of the Registration
Statement on Form S-8 (the "REGISTRATION STATEMENT"), filed with the Securities
and Exchange Commission under the Securities Act of 1933, as amended, relating
to the registration of 1,800,000 shares of Common Stock, par value $1.00 per
share (the "COMMON STOCK"), of the Company that may be issued pursuant to the
Trinity Industries, Inc. 1998 Stock Option and Incentive Plan, as amended (the
"STOCK OPTION PLAN").

In connection therewith, we have examined (i) the Company's Certificate of
Incorporation, as amended (the "CERTIFICATE OF INCORPORATION"), and the Bylaws
(the "BYLAWS") of the Company, as amended, (ii) minutes, records and resolutions
of the corporate proceedings of the Company with respect to the adoption and
amendment of the Stock Option Plan and the granting of awards thereunder, and
(iii) such other documents as we have deemed necessary for the expression of the
opinion contained herein.

In making the foregoing examination, 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 questions of fact material to this
opinion, where such facts have not been independently established, and as to the
content and form of the Certificate of Incorporation, Bylaws, minutes, records,
resolutions and other documents or writings of the Company, we have relied, to
the extent we deem 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 the foregoing, and having due regard for such legal considerations as
we deem relevant, we are of the opinion that the 1,800,000 shares of Common
Stock covered by the




Trinity Industries, Inc.
April 5, 2002
Page Two




Registration Statement, which may be issued from time to time in accordance with
the terms of the Stock Option Plan, have been duly authorized for issuance by
the Company, and, when so issued in accordance with the terms and conditions of
the Stock Option Plan and any related stock option agreement or other applicable
agreements, will be validly issued, fully paid and nonassessable.

The opinion expressed herein is limited to the federal laws of the United States
of America, and, to the extent relevant to the opinion expressed herein, the
General Corporation Law of the State of Delaware (the "DGCL") and applicable
provisions of the Delaware Constitution, in each case as currently in effect,
and judicial decisions reported as of the date hereof and interpreting the DGCL
and such provisions of the Delaware Constitution.

We hereby consent to the filing of this opinion with the Securities and Exchange
Commission as an exhibit to the Registration Statement.

Very truly yours,

/s/ HAYNES AND BOONE, LLP

Haynes and Boone, LLP