Exhibit 99.1

FOR RELEASE: IMMEDIATE

GATX CORPORATION REPORTS 2012 THIRD QUARTER RESULTS

CHICAGO, IL, October 18, 2012 – GATX Corporation (NYSE:GMT) today reported 2012 third quarter net income of $53.8 million or $1.13 per diluted share, compared to 2011 third quarter net income of $32.9 million or $.70 per diluted share. The 2012 and 2011 third quarter results include benefits from Tax Adjustments and Other Items of $18.2 million or $.38 per diluted share and $1.3 million or $.03 per diluted share, respectively.

Net income for the first nine months of 2012 was $107.6 million or $2.26 per diluted share, compared to $79.2 million or $1.68 per diluted share in the prior year period. The 2012 and 2011 year-to-date results include benefits from Tax Adjustments and Other Items of $0.7 million or $.02 per diluted share and $13.9 million or $.30 per diluted share, respectively. Details related to the Tax Adjustments and Other Items are provided in the attached Supplemental Information.

Brian A. Kenney, president and chief executive officer of GATX, said, “Driven by unprecedented demand for tank cars, our North American rail fleet continues to exhibit excellent performance. During the third quarter, the renewal rate change of GATX’s Lease Price Index (“LPI”) was a positive 26.4% and the average renewal term for cars in the LPI was 59 months. Fleet utilization remains above 98%, and our renewal success rate was just over 80% during the quarter. The historically high renewal success rate GATX achieved over the last 18 months has also contributed to lower railcar maintenance expense over that period. Much of this maintenance expense has been permanently avoided as GATX did not incur costs to prepare cars for other customers. However, a portion of the savings represents maintenance expense that will be incurred when the cars come in for service in future years.”

Mr. Kenney continued, “In Europe, demand for tank cars remains solid with over 96% fleet utilization, although there are signs of weakening in the chemical market. Year-to-date investment volume in Europe is over $125 million, reflective of our favorable long-term outlook for new tank car demand and opportunities resulting from industry-wide fleet modernization.

“American Steamship Company (“ASC”) experienced favorable sailing conditions and steady customer demand. ASC continues to operate 14 of its vessels. In the Portfolio Management segment, Rolls-Royce and Partners Finance had another quarter of solid performance and benefited from asset remarketing activity.”

Mr. Kenney concluded, “Based on year-to-date results, we expect 2012 full-year earnings to be at the high end of our previous guidance range of $2.65—$2.75 per diluted share, excluding any impact related to Tax Adjustments and Other Items.”

RAIL

Rail segment profit was $63.5 million in the third quarter of 2012, compared to $63.0 million in the third quarter of 2011. The 2012 and 2011 third quarter results include the negative pre-tax impact from Other Items of $2.1 million and $3.1 million, respectively. Excluding the impact from Other Items, segment profit was slightly lower compared to the prior year period primarily due to less remarketing activity, lower scrap rates and an increase in other expenses. These items were partially offset by an increase in lease income driven by higher lease rates, and the favorable impact of a change in depreciation policy at GATX’s European rail affiliate, AAE Cargo.

Rail reported segment profit of $171.7 million year-to-date 2012, compared to $171.3 million in the same period of 2011. The 2012 and 2011 year-to-date results include the negative pre-tax impact from Other Items of $20.9 million and a pre-tax benefit from Other Items of $11.0 million, respectively. Segment profit improved compared to the prior year period primarily due to higher lease rates and lower maintenance expense which resulted from a high renewal success rate in the current year.

Demand for tank cars continues at record levels, while demand for freight cars is inconsistent across markets and soft in particular car types including coal.

At September 30, 2012, Rail’s North American fleet was approximately 109,000 cars. Fleet utilization was 98.2% compared to 98.3% at the end of the second quarter and 98.2% at the end of third quarter 2011. The GATX Lease Price Index (“LPI”), a weighted average lease renewal rate for a group of railcars representative of GATX’s North American fleet, increased 26.4% over the weighted average expiring lease rate in the third quarter. This compares to a 23.9% increase in the LPI during the second quarter and a 9.6% increase during the third quarter of 2011. The average lease renewal term for cars included in the LPI during the third quarter was 59 months, consistent with the second quarter and up from 49 months in the third quarter of 2011.

Rail’s European wholly-owned tank car fleet was approximately 21,000 cars and utilization was 96.6% at the end of the third quarter, compared to 96.3% at the end of the second quarter and 96.0% at the end of third quarter 2011.

Additional current and historical fleet and operating data as well as macroeconomic data related to Rail’s business can be found on the last page of this press release.

AMERICAN STEAMSHIP COMPANY

American Steamship Company (“ASC”) reported segment profit of $13.2 million in the third quarter 2012 compared to $8.5 million in the third quarter 2011. Segment profit year-to-date 2012 was $29.3 million, compared to $17.9 million year-to-date 2011. ASC carried 20.9 million net tons through the third quarter of 2012 compared to 18.6 million net tons in the same period of 2011. The increased tonnage, improved rates and the negative impact on the prior year results due to a strike by members of the American Maritime Officers union drove the improvement in segment profit.

PORTFOLIO MANAGEMENT

Portfolio Management reported segment profit of $15.0 million in the third quarter of 2012 compared to $11.5 million in third quarter 2011. The improvement in segment profit is attributable to increased asset remarketing activity by Rolls-Royce and Partners Finance (“RRPF”) and an asset impairment loss recognized in the prior year period on six vessels GATX received upon the dissolution of the Clipper Fourth joint venture, partially offset by decreased asset remarketing activity in the third quarter of 2012.

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Segment profit year-to-date 2012 was $51.6 million, compared to $31.0 million year-to-date 2011. The segment profit increase in the current year is driven by improved asset remarketing results by RRPF, the previously noted asset impairment loss in the prior year and increased asset remarketing activity in 2012.

At September 30, 2012, the Portfolio Management segment consisted of approximately $815.1 million of owned assets and third-party managed portfolios of approximately $147.5 million.

COMPANY DESCRIPTION

GATX Corporation (NYSE:GMT) strives to be recognized as the finest railcar leasing company in the world by its customers, its shareholders, its employees and the communities where it operates. Controlling one of the largest railcar fleets in the world, GATX has been providing quality railcars and services to its customers for 114 years. GATX has been headquartered in Chicago, Illinois since its founding in 1898 and has traded on the New York Stock Exchange since 1916. For more information, visit the Company’s website at www.gatx.com.

TELECONFERENCE INFORMATION

GATX Corporation will hold a conference call to discuss the 2012 third quarter results. Investors may listen to the call either via telephone or over the Internet as follows:

Thursday, October 18^th

11:00 A.M. Eastern Time

Domestic Dial-In:         1-800-862-9098

International Dial-In:   1-785-424-1051

Live Webcast: www.gatx.com

Replay: 1-888-203-1112 or 1-719-457-0820/ Access Code: 1540385

Call-in details, a copy of this press release and real-time audio access are available at www.gatx.com. Please access the call 15 minutes prior to the start time. Following the call, a replay will be available on the same site.

FORWARD-LOOKING STATEMENTS

This document contains statements that may constitute forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934 and are subject to the safe harbor provisions of those sections and the Private Securities Litigation Reform Act of 1995. Some of these statements may be identified by words like “anticipate,” “believe,” “estimate,” “expect,” “intend,” “plan,” “predict,” “project” or other similar words. Investors are cautioned that any such forward-looking statements are not guarantees of future performance and involve risks and uncertainties, including those described in GATX’s Annual Report on Form 10-K for the year ended December 31, 2011 and other filings with the SEC, and that actual results or developments may differ materially from those in the forward-looking statements.

Specific factors that might cause actual results to differ from expectations include, but are not limited to, (1) general economic, market, regulatory and political conditions affecting the rail, marine and other industries served by GATX and its customers; (2) competitive factors in GATX’s primary markets, including lease pricing and asset availability; (3) lease rates, utilization levels and operating costs in GATX’s primary operating segments; (4) conditions in the capital markets or changes in GATX’s credit ratings and financing costs; (5) risks related to compliance with, or changes to, laws, rules and regulations applicable to GATX and its rail, marine and other assets; (6) costs associated with maintenance initiatives; (7) operational and financial risks associated with long-term railcar purchase commitments; (8) changes in loss provision levels within GATX’s portfolio; (9) conditions affecting certain assets, customers or regions where GATX has a large investment; (10) impaired asset charges that may result from changing market conditions or portfolio management decisions implemented by GATX; (11) opportunities for remarketing income; (12) labor relations with unions representing GATX employees; and (13) the outcome of pending or threatened litigation.

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Given these risks and uncertainties, readers are cautioned not to place undue reliance on these forward-looking statements, which reflect management’s analysis, judgment, belief or expectation only as of the date hereof. GATX has based these forward-looking statements on information currently available and disclaims any intention or obligation to update or revise these forward-looking statements to reflect subsequent events or circumstances.

FOR FURTHER INFORMATION CONTACT:

GATX Corporation

Jennifer Van Aken

312-621-6689

jennifer.vanaken@gatx.com

Investor, corporate, financial, historical financial, photographic and news release information may be found at www.gatx.com.

(10/18/12)

—Tabular Follows—

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GATX CORPORATION AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

(In Millions, Except Per Share Data)

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GATX CORPORATION AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

(In Millions, Except Per Share Data)

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GATX CORPORATION AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS (UNAUDITED)

(In Millions)

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GATX CORPORATION AND SUBSIDIARIES

SEGMENT DATA (UNAUDITED)

Three Months Ended September 30, 2012

(In Millions)

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GATX CORPORATION AND SUBSIDIARIES

SEGMENT DATA (UNAUDITED)

Nine Months Ended September 30, 2012

(In Millions)

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GATX CORPORATION AND SUBSIDIARIES

SEGMENT DATA (UNAUDITED)

Three Months Ended September 30, 2011

(In Millions)

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GATX CORPORATION AND SUBSIDIARIES

SEGMENT DATA (UNAUDITED)

Nine Months Ended September 30, 2011

(In Millions)