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<title>SEC FORM 
            4</title>
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<body>SEC Form 4 
   <table width="100%" border="0" cellspacing="0" cellpadding="4">
<tr>
<td width="20%" colspan="2" valign="top" align="center" class="FormName">FORM 4</td>
<td rowspan="2" width="60%" valign="middle" align="center">
<span class="FormTitle">UNITED STATES SECURITIES AND EXCHANGE COMMISSION</span><br><span class="MedSmallFormText">Washington, D.C. 20549</span><br><br><span class="FormTitle">STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP</span><br><br><span class="MedSmallFormText">Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934</span><br><span class="MedSmallFormText">or Section 30(h) of the Investment Company Act of 1940</span>
</td>
<td rowspan="2" width="20%" valign="top" align="center"><table width="100%" border="1" summary="OMB Approval Status Box">
<tr><td class="FormTextC">OMB APPROVAL</td></tr>
<tr><td><table width="100%" border="0" summary="OMB Interior Box">
<tr>
<td class="SmallFormText" colspan="3">OMB Number:</td>
<td class="SmallFormTextR">3235-0287</td>
</tr>
<tr><td class="SmallFormText" colspan="4">Estimated average burden</td></tr>
<tr>
<td class="SmallFormText" colspan="3">hours per response:</td>
<td class="SmallFormTextR">0.5</td>
</tr>
</table></td></tr>
</table></td>
</tr>
<tr valign="middle">
<td><table width="100%" border="1" cellpadding="0" cellspacing="0"><tr><td>  </td></tr></table></td>
<td class="SmallFormText">Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. 
         <i>See</i>

         Instruction 1(b).</td>
</tr>
<tr valign="middle">
<td><table width="100%" border="1" cellpadding="0" cellspacing="0"><tr><td>  </td></tr></table></td>
<td class="SmallFormText">Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10. </td>
</tr>
</table>
<table width="100%" border="1" cellspacing="0" cellpadding="4">
<tr>
<td rowspan="4" width="35%" valign="top">
<span class="MedSmallFormText">1. Name and Address of Reporting Person<sup>*</sup></span><table border="0" width="100%"><tr><td><a href="/cgi-bin/browse-edgar?action=getcompany&amp;CIK=0001888602">Jones Alexander B</a></td></tr></table>
<hr width="98%">
<table border="0" width="100%"><tr>
<td width="33%" class="MedSmallFormText">(Last)</td>
<td width="33%" class="MedSmallFormText">(First)</td>
<td width="33%" class="MedSmallFormText">(Middle)</td>
</tr></table>
<table border="0" width="100%">
<tr><td><span class="FormData">590 1ST AVE. S</span></td></tr>
<tr><td><span class="FormData">UNIT C1</span></td></tr>
</table>
<hr width="98%">
<span class="MedSmallFormText">(Street)</span><table border="0" width="100%"><tr>
<td width="33%"><span class="FormData">SEATTLE</span></td>
<td width="33%"><span class="FormData">WA</span></td>
<td width="33%"><span class="FormData">98104</span></td>
</tr></table>
<hr width="98%">
<table border="0" width="100%"><tr>
<td width="33%" class="MedSmallFormText">(City)</td>
<td width="33%" class="MedSmallFormText">(State)</td>
<td width="33%" class="MedSmallFormText">(Zip)</td>
</tr></table>
</td>
<td width="35%" valign="top">
<span class="MedSmallFormText">2. Issuer Name <b>and</b> Ticker or Trading Symbol
      </span><br><a href="/cgi-bin/browse-edgar?action=getcompany&amp;CIK=0000352825">FOSTER L B CO</a>
     [ <span class="FormData">FSTR</span> ]
   </td>
<td rowspan="2" valign="top">
<span class="MedSmallFormText">5. Relationship of Reporting Person(s) to Issuer
      </span><br><span class="MedSmallFormText">(Check all applicable)</span><table border="0" width="100%">
<tr>
<td width="15%" align="center"><span class="FormData">X</span></td>
<td width="35%" class="MedSmallFormText">Director</td>
<td width="15%" align="center"></td>
<td width="35%" class="MedSmallFormText">10% Owner</td>
</tr>
<tr>
<td align="center"></td>
<td class="MedSmallFormText">Officer (give title below)</td>
<td align="center"><span class="FormData">X</span></td>
<td class="MedSmallFormText">Other (specify below)</td>
</tr>
<tr>
<td width="15%" align="center"></td>
<td width="35%" align="left" style="color: blue"></td>
<td width="15%" align="center"></td>
<td width="35%" align="left" style="color: blue">See Explanation of Responses</td>
</tr>
</table>
</td>
</tr>
<tr><td valign="top">
<span class="MedSmallFormText">3. Date of Earliest Transaction
         (Month/Day/Year)</span><br><span class="FormData">09/30/2025</span>
</td></tr>
<tr>
<td valign="top">
<span class="MedSmallFormText">4. If Amendment, Date of Original Filed
         (Month/Day/Year)</span><br>
</td>
<td valign="top">
<span class="MedSmallFormText">6. Individual or Joint/Group Filing (Check Applicable Line)
      </span><table border="0" width="100%">
<tr>
<td width="15%" align="center"><span class="FormData">X</span></td>
<td width="85%" class="MedSmallFormText">Form filed by One Reporting Person</td>
</tr>
<tr>
<td width="15%" align="center"></td>
<td width="85%" class="MedSmallFormText">Form filed by More than One Reporting Person</td>
</tr>
</table>
</td>
</tr>
</table>
<table width="100%" border="1" cellspacing="0" cellpadding="4">
<thead>
<tr><th width="100%" valign="top" colspan="11" align="center" class="FormTextC"><b>Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned</b></th></tr>
<tr>
<th width="36%" valign="top" rowspan="2" align="left" class="MedSmallFormText">1. Title of Security (Instr. 
      3)
   </th>
<th width="6%" valign="top" rowspan="2" align="left" class="SmallFormText">2. Transaction Date
      (Month/Day/Year)</th>
<th width="5%" valign="top" rowspan="2" align="left" class="SmallFormText">2A. Deemed Execution Date, if any
      (Month/Day/Year)</th>
<th width="7%" valign="top" colspan="2" align="left" class="SmallFormText">3. Transaction Code (Instr. 
      8)
   </th>
<th width="19%" valign="top" colspan="3" align="left" class="SmallFormText">4. Securities Acquired (A) or Disposed Of (D) (Instr. 
      3, 4 and 5)
   </th>
<th width="11%" valign="top" rowspan="2" align="left" class="SmallFormText">5. 
      Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 
      3 and 4)
   </th>
<th width="9%" valign="top" rowspan="2" align="left" class="SmallFormText">6. Ownership Form: Direct (D) or Indirect (I) (Instr. 
      4)
   </th>
<th width="8%" valign="top" rowspan="2" align="left" class="SmallFormText">7. Nature of Indirect Beneficial Ownership (Instr. 
      4)
   </th>
</tr>
<tr>
<th width="4%" align="center" class="SmallFormText">Code</th>
<th width="3%" align="center" class="SmallFormText">V</th>
<th width="8%" align="center" class="SmallFormText">Amount</th>
<th width="5%" align="center" class="SmallFormText">(A) or (D)</th>
<th width="6%" align="center" class="SmallFormText">Price</th>
</tr>
</thead>
<tbody><tr>
<td align="left">
<span class="FormData">Common Stock</span><span class="FootnoteData"><sup>(1)</sup></span>
</td>
<td align="center"><span class="FormData">09/30/2025</span></td>
<td align="center"><span class="FormData"></span></td>
<td align="center"><span class="SmallFormData">A</span></td>
<td align="center"></td>
<td align="center">
<span class="FormData">649</span><span class="FootnoteData"><sup>(2)</sup></span>
</td>
<td align="center"><span class="FormData">A</span></td>
<td align="center">
<span class="FormText">$</span><span class="FormData">26.95</span>
</td>
<td align="center"><span class="FormData">13,138</span></td>
<td align="center"><span class="FormData">D</span></td>
<td align="left"></td>
</tr></tbody>
</table>
<table width="100%" border="1" cellspacing="0" cellpadding="4"><thead>
<tr><th width="100%" valign="top" colspan="16" align="center" class="FormTextC">
<b>Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned</b><br><b>(e.g., puts, calls, warrants, options, convertible securities)</b>
</th></tr>
<tr>
<th width="13%" valign="top" rowspan="2" align="left" class="SmallFormText">1. Title of Derivative Security (Instr. 
      3)
   </th>
<th width="5%" valign="top" rowspan="2" align="left" class="SmallFormText">2. Conversion or Exercise Price of Derivative Security
   </th>
<th width="5%" valign="top" rowspan="2" align="left" class="SmallFormText">3. Transaction Date
      (Month/Day/Year)</th>
<th width="5%" valign="top" rowspan="2" align="left" class="SmallFormText">3A. Deemed Execution Date, if any
      (Month/Day/Year)</th>
<th width="9%" valign="top" colspan="2" align="left" class="SmallFormText">4. Transaction Code (Instr. 
      8)
   </th>
<th width="10%" valign="top" colspan="2" align="left" class="SmallFormText">5. 
      Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 
      3, 4 and 5)
   </th>
<th width="9%" valign="top" colspan="2" align="left" class="SmallFormText">6. Date Exercisable and Expiration Date 
      (Month/Day/Year)</th>
<th width="17%" valign="top" colspan="2" align="left" class="SmallFormText">7. Title and Amount of Securities Underlying Derivative Security (Instr. 
      3 and 4)
   </th>
<th width="6%" valign="top" rowspan="2" align="left" class="SmallFormText">8. Price of Derivative Security (Instr. 
      5)
   </th>
<th width="6%" valign="top" rowspan="2" align="left" class="SmallFormText">9. 
      Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 
      4)
   </th>
<th width="6%" valign="top" rowspan="2" align="left" class="SmallFormText">10. Ownership Form: Direct (D) or Indirect (I) (Instr. 
      4)
   </th>
<th width="7%" valign="top" rowspan="2" align="left" class="SmallFormText">11. Nature of Indirect Beneficial Ownership (Instr. 
      4)
   </th>
</tr>
<tr>
<th width="4%" valign="bottom" align="center" class="SmallFormText">Code</th>
<th width="4%" valign="bottom" align="center" class="SmallFormText">V</th>
<th width="5%" valign="bottom" align="center" class="SmallFormText">(A)</th>
<th width="5%" valign="bottom" align="center" class="SmallFormText">(D)</th>
<th width="5%" valign="bottom" align="center" class="SmallFormText">Date Exercisable</th>
<th width="4%" valign="bottom" align="center" class="SmallFormText">Expiration Date</th>
<th width="10%" valign="bottom" align="center" class="SmallFormText">Title</th>
<th width="7%" valign="bottom" align="center" class="SmallFormText">Amount or Number of Shares</th>
</tr>
</thead></table>
<table border="0" width="100%">
<tr><td class="MedSmallFormText"><b>Explanation of Responses:</b></td></tr>
<tr><td class="FootnoteData">1. The Reporting Person may be deemed to be a member of a Section 13(d) group that collectively beneficially owns more than 10% of the Issuer's outstanding Common Stock. The Reporting Person disclaims beneficial ownership of the securities of the Issuer owned directly by other members of the Section 13(d) group and this report shall not be deemed an admission that he is the beneficial owner of such securities for purposes of Section 16 or for any other purpose. The Reporting Person also serves as a director of the Issuer.</td></tr>
<tr><td class="FootnoteData">2. Represents the Reporting Person's quarterly director cash retainer fees, which were elected to be paid in stock.</td></tr>
</table>
<table width="100%" border="0">
<tr>
<td width="60%"></td>
<td width="20%"><u><span class="FormData">/s/ Alexander B. Jones</span></u></td>
<td width="20%"><u><span class="FormData">10/02/2025</span></u></td>
</tr>
<tr>
<td></td>
<td class="MedSmallFormText">** Signature of Reporting Person</td>
<td class="MedSmallFormText">Date</td>
</tr>
<tr><td colspan="3" class="MedSmallFormText">Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.</td></tr>
<tr><td colspan="3" class="MedSmallFormText">* If the form is filed by more than one reporting person, 
                  <i>see</i>

                  Instruction 
                  4

                  (b)(v).</td></tr>
<tr><td colspan="3" class="MedSmallFormText">** Intentional misstatements or omissions of facts constitute Federal Criminal Violations 
                  <i>See</i>

                  18 U.S.C. 1001 and 15 U.S.C. 78ff(a).</td></tr>
<tr><td colspan="3" class="MedSmallFormText">Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, 
                  <i>see</i>

                  Instruction 6 for procedure.</td></tr>
<tr><td colspan="3" class="MedSmallFormText"><b>Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.</b></td></tr>
</table>
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