<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-12-31</periodOfReport>
    <issuer>
        <issuerCik>0000099780</issuerCik>
        <issuerName>TRINITY INDUSTRIES INC</issuerName>
        <issuerTradingSymbol>NYSE/TRN</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001195484</rptOwnerCik>
            <rptOwnerName>WALLACE TIMOTHY R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2525 STEMMONS FREEWAY</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75207</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Chairman, President &amp; CEO</officerTitle></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeTransaction><securityTitle><value>Trinity Stock Units</value></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F2"/></conversionOrExercisePrice><transactionDate><value>2003-12-31</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>49</value></transactionShares><transactionPricePerShare><value>30.84</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>49</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>36766</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>by Trust</value></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>Trinity Phantom Stock Units</value></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F1"/></conversionOrExercisePrice><transactionDate><value>2003-12-31</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>86</value></transactionShares><transactionPricePerShare><value>30.84</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F1"/></exerciseDate><expirationDate><footnoteId id="F1"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>86</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>2557</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">The Trinity Phantom Stock Units were accrued under the Trinity Industries, Inc. Deferred Plan for Directors Fees.  Stock units are converted at   &quot;1 - for - 1&quot; (a rate of one stock unit per one share of Trinity common stock).  Settlement of the account will be in cash after the reporting person's retirement.  </footnote><footnote id="F2">The Trinity Stock Units were accrued under the Trinity Industries, Inc. Supplemental Profit Sharing Plan and will be settled upon the reporting  person's retirement or other termination of service or earlier for in service distributions under limited circumstances as provided by the plan.  Stock Units convert at a ratio of 1 to 1.</footnote></footnotes><remarks/><ownerSignature><signatureName>Michael G. Fortado  For:  Timothy R. Wallace</signatureName><signatureDate>2004-01-05</signatureDate></ownerSignature></ownershipDocument>
[{"type": "4", "sequence": "1", "filename": "edgar.xml", "description": "PRIMARY DOCUMENT", "secsgml_size_bytes": 4662}]
X0201
4
2003-12-31
0000099780
TRINITY INDUSTRIES INC
NYSE/TRN
0001195484
WALLACE TIMOTHY R
2525 STEMMONS FREEWAY
DALLAS
TX
75207
1
1
0
0
Chairman, President & CEO
Trinity Stock Units
0
2003-12-31
4
A
0
49
30.84
A
Common Stock
49
36766
I
by Trust
Trinity Phantom Stock Units
0
2003-12-31
4
A
0
86
30.84
A
Common Stock
86
2557
D
The Trinity Phantom Stock Units were accrued under the Trinity Industries, Inc. Deferred Plan for Directors Fees.  Stock units are converted at   "1 - for - 1" (a rate of one stock unit per one share of Trinity common stock).  Settlement of the account will be in cash after the reporting person's retirement.
The Trinity Stock Units were accrued under the Trinity Industries, Inc. Supplemental Profit Sharing Plan and will be settled upon the reporting  person's retirement or other termination of service or earlier for in service distributions under limited circumstances as provided by the plan.  Stock Units convert at a ratio of 1 to 1.
Michael G. Fortado  For:  Timothy R. Wallace
2004-01-05