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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2012-07-25</periodOfReport>

    <dateOfOriginalSubmission>2012-07-26</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000002230</issuerCik>
        <issuerName>ADAMS EXPRESS CO</issuerName>
        <issuerTradingSymbol>ADX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001353074</rptOwnerCik>
            <rptOwnerName>Prue Nancy J F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PETROLEUM &amp; RESOURCES CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>7 SAINT PAUL STREET</rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-07-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.58</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>27314.348</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Of these shares, 11,097.278 are held by the undersigned directly and include 25.574 shares that were acquired in exempt transactions as a result of dividend reinvestment from January 1, 2012 to July 25, 2012.  In addition, 7,119.36 of these shares are held indirectly by the undersigned proportionate beneficial interest in such stock held in the Issuer's Thrift Plan Trust, and 9,097.71 are held by Petroleum &amp; Resources Corporation Thrift Plan Trust.  Such number is based on information as of July 25, 2012.  This number reflects periodic contributions made during 2012, shares acquired by the Trustee through dividend reinvestment in 2012, and changes in the number of shares previously reported due to fluctuations in the market price and interest in the Issuer's Thrift Plan Trust.  The Issuer's stock traded in a range of $9.79 - $11.11 during the period.</footnote>
        <footnote id="F2">The total number of shares beneficially owned and the numer of shares directly held were underreported on the 07/26/2012 filing.  The correct amount of shares beneficially owned was 27,314.348 adn the number of shares directly held was 11,097.278.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Nancy J.F. Prue</signatureName>
        <signatureDate>2012-08-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
