<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2014-06-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000099106</issuerCik>
        <issuerName>TRANS LUX Corp</issuerName>
        <issuerTradingSymbol>TNLX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001612877</rptOwnerCik>
            <rptOwnerName>Shi Yaozhong</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>950 THIRD AVENUE, SUITE 2804</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2014-06-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>333333</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>6</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>333333</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Director, Member and Majority Owner of owner of shares</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Warrants</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>8</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2014-06-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>33333</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>8</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2014-06-27</value>
            </exerciseDate>
            <expirationDate>
                <value>2016-06-26</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>33333</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>33333</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Director, member and majority owner of owner of deriviative securities</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares are owned by Retop Industrial (Hong Kong) Limited and were previously acquired by such entity on 06/27/2014.  After a recent reorganization of this entity, I am now a diretor, member and majority owner of Retop Industrial (Hong Kong) Limited as of 07/30/2014.  I exercise voting and dispositive rights over the shares, and am a director, member and majority owner of Retop Industrial (Hong Kong) Limited.</footnote>
        <footnote id="F2">The warrants are owned by Retop Industrial (Hong Kong) Limited and were previously acquired by such entity on 06/27/2014.  After a recent reorganization of this entity, I am now a diretor, member and majority owner of Retop Industrial (Hong Kong) Limited as of 07/30/2014.  I exercise voting and dispositive rights over the underlying shares, and am a director, member and majority owner of Retop Industrial (Hong Kong) Limited.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Yaozhong Shi</signatureName>
        <signatureDate>2014-09-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0306
4
2014-06-27
0
0000099106
TRANS LUX Corp
TNLX
0001612877
Shi Yaozhong
950 THIRD AVENUE, SUITE 2804
NEW YORK
NY
10022
1
0
0
0
Common Stock
2014-06-27
4
A
0
333333
6
A
333333
I
Director, Member and Majority Owner of owner of shares
Warrants
8
2014-06-27
4
A
0
33333
8
A
2014-06-27
2016-06-26
Common Stock
33333
33333
I
Director, member and majority owner of owner of deriviative securities
The shares are owned by Retop Industrial (Hong Kong) Limited and were previously acquired by such entity on 06/27/2014.  After a recent reorganization of this entity, I am now a diretor, member and majority owner of Retop Industrial (Hong Kong) Limited as of 07/30/2014.  I exercise voting and dispositive rights over the shares, and am a director, member and majority owner of Retop Industrial (Hong Kong) Limited.
The warrants are owned by Retop Industrial (Hong Kong) Limited and were previously acquired by such entity on 06/27/2014.  After a recent reorganization of this entity, I am now a diretor, member and majority owner of Retop Industrial (Hong Kong) Limited as of 07/30/2014.  I exercise voting and dispositive rights over the underlying shares, and am a director, member and majority owner of Retop Industrial (Hong Kong) Limited.
Yaozhong Shi
2014-09-02