Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Receivables, allowance for doubtful accounts	$ 4.5	$ 3.1
Restricted cash	234.7	260.7
Property, plant and equipment, at cost	6,586.0us-gaap_PropertyPlantAndEquipmentGross	6,275.8us-gaap_PropertyPlantAndEquipmentGross
Less: accumulated depreciation	1,683.1	1,505.2
Unamortized discount on recourse debt	60.0	74.1
Preferred stock, shares authorized	1,500,000us-gaap_PreferredStockSharesAuthorized	1,500,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares unissued	1,500,000trn_PreferredStockSharesUnissued	1,500,000trn_PreferredStockSharesUnissued
Common stock, shares authorized	200,000,000us-gaap_CommonStockSharesAuthorized	200,000,000us-gaap_CommonStockSharesAuthorized
Common stock, shares issued	155,700,000us-gaap_CommonStockSharesIssued	81,700,000us-gaap_CommonStockSharesIssued
Common stock, shares outstanding	155,700,000us-gaap_CommonStockSharesOutstanding	81,700,000us-gaap_CommonStockSharesOutstanding
Treasury stock, shares	100,000us-gaap_TreasuryStockShares	4,300,000us-gaap_TreasuryStockShares
Partially-owned subsidiaries
Restricted cash	91.9	77.1
Property, plant and equipment, at cost	2,261.2	1,887.2
Less: accumulated depreciation	$ 261.3	$ 202.1

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