TRINITY INDUSTRIES INC

14221 N. Dallas Parkway, Suite 1100Dallas, Texas 75254www.trin.net

PROXY STATEMENT FOR ANNUAL MEETING OF STOCKHOLDERS

To Be Held on May 15, 2025

This Proxy Statement is being provided to the stockholders of Trinity Industries, Inc. (the “Company”) in connection with the solicitation of proxies by the Company's Board of Directors to be voted at the Annual Meeting of Stockholders to be held at 14221 N. Dallas Parkway, Dallas, Texas, on Thursday, May 15, 2025, at 8:30 a.m., Central Daylight Time (the “Annual Meeting”), or at any postponement or adjournment thereof, for the purposes set forth in the accompanying Notice of Annual Meeting of Stockholders. The Company’s mailing address is 14221 N. Dallas Parkway, Suite 1100, Dallas, Texas 75254.

To both save money and protect the environment, the Company has elected to provide access to its proxy materials and Annual Report to Stockholders for the fiscal year ended December 31, 2024 (“2024 Annual Report”) on the internet, instead of mailing the full set of printed proxy materials, in accordance with the rules of the Securities and Exchange Commission (“SEC”) for the electronic distribution of proxy materials. Proxy materials or a Notice of Internet Availability of Proxy Materials (the “Notice”) are being first released or mailed to stockholders on or about April 3, 2025. If you received a Notice by mail, you will not receive a printed copy of the proxy materials in the mail unless you request it. Instead, the Notice instructs you how to obtain and review the important information contained in the Proxy Statement and 2024 Annual Report. The Notice also instructs you how to submit your proxy over the internet. If you received a Notice by mail and would like to receive a printed copy of the proxy materials, you should follow the instructions for requesting such materials included in the Notice.

All stockholders of record can vote by telephone using the toll-free telephone number on the Notice or proxy card, or via the internet atwww.proxyvote.com, and using the procedures and instructions described on the Notice or proxy card. You will need the 16-digit control number provided in your proxy materials. If you are a stockholder of record and receive a Notice card, you may request a written proxy card by following the instructions included in the Notice. To vote your proxy by mail using a written proxy card, mark your vote on the proxy card, then follow the instructions on the card. You may vote in person by attending the meeting.

The named proxies will vote your shares according to your directions. If you sign and return your proxy but do not make any of the selections, the named proxies will vote your shares: (i) FOR election of the eight nominees for directors as set forth in this Proxy Statement, (ii) FOR approval, on an advisory basis, of the compensation of the Company’s named executive officers as disclosed in these materials, and (iii) FOR ratification of Ernst & Young LLP as the independent registered public accounting firm of the Company for the fiscal year ending December 31, 2025. The proxy may be revoked at any time before it is exercised by filing with the Company a written revocation addressed to the Corporate Secretary, by executing a proxy bearing a later date, or by attending the Annual Meeting and voting in person.

The cost of soliciting proxies will be borne by the Company. In addition to the use of postal services or the internet, proxies may be solicited by directors, officers, and regular employees of the Company (none of whom will receive any additional compensation for any assistance they may provide in the solicitation of proxies) in person or by telephone. The Company has hired Georgeson, Inc. to assist in the solicitation of proxies at an estimated cost of $15,000 plus expenses.

The outstanding voting securities of the Company consist of shares of common stock, $0.01 par value per share (“Common Stock”). The record date for the determination of the stockholders entitled to notice of and to vote at the Annual Meeting, or any postponement or adjournment thereof, has been established by the Board of Directors as the close of business on March 17, 2025. At that date, there were outstanding and entitled to vote 81,632,093 shares of Common Stock.

The presence, in person or by proxy, of the holders of record of a majority of the outstanding shares entitled to vote is necessary to constitute a quorum for the transaction of business at the Annual Meeting, but if a quorum should not be present, the meeting may be adjourned from time to time until a quorum is obtained. A holder of Common Stock will be entitled to one vote per share on each matter properly brought before the meeting. Cumulative voting is not permitted in the election of directors.

Votes may be cast individually for or against any of the director nominees. Shares of a stockholder who abstains from voting on any or all proposals will be included for the purpose of determining the presence of a quorum. Broker non-votes on any matter, as to which the broker has indicated on the proxy that it does not have discretionary authority to vote, will be treated as votes not cast or as shares not entitled to vote with respect to that matter and will not affect the outcome of the vote. However, such shares will be considered present and entitled to vote for quorum purposes so long as they are entitled to vote on at least one matter.