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<title>SEC FORM 
            4/A</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=0001600919">Guinee Patrick J.</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">L.B. FOSTER COMPANY</span></td></tr>
<tr><td><span class="FormData">415 HOLIDAY DRIVE, SUITE 100</span></td></tr>
</table>
<hr width="98%">
<span class="MedSmallFormText">(Street)</span><table border="0" width="100%"><tr>
<td width="33%"><span class="FormData">PITTSBURGH</span></td>
<td width="33%"><span class="FormData">PA</span></td>
<td width="33%"><span class="FormData">15220</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"></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"><span class="FormData">X</span></td>
<td class="MedSmallFormText">Officer (give title below)</td>
<td align="center"></td>
<td class="MedSmallFormText">Other (specify below)</td>
</tr>
<tr>
<td width="15%" align="center"></td>
<td width="35%" align="left" style="color: blue">EVP General Counsel &amp; Sec.</td>
<td width="15%" align="center"></td>
<td width="35%" align="left" style="color: blue"></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">02/19/2026</span>
</td></tr>
<tr>
<td valign="top">
<span class="MedSmallFormText">4. If Amendment, Date of Original Filed
         (Month/Day/Year)</span><br><span class="FormData">02/23/2026</span>
</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></td>
<td align="center"><span class="FormData">02/19/2026</span></td>
<td align="center"></td>
<td align="center"><span class="SmallFormData">A</span></td>
<td align="center"></td>
<td align="center">
<span class="FormData">7,170</span><span class="FootnoteData"><sup>(1)</sup></span>
</td>
<td align="center"><span class="FormData">A</span></td>
<td align="center">
<span class="FormText">$</span><span class="FormData">0</span>
</td>
<td align="center">
<span class="FormData">88,298</span><span class="FootnoteData"><sup>(2)</sup></span><span class="FootnoteData"><sup>(3)</sup></span><span class="FootnoteData"><sup>(4)</sup></span>
</td>
<td align="center"><span class="FormData">D</span></td>
<td align="left"></td>
</tr>
<tr>
<td align="left"><span class="FormData">Common Stock</span></td>
<td align="center"><span class="FormData">02/19/2026</span></td>
<td align="center"></td>
<td align="center"><span class="SmallFormData">A</span></td>
<td align="center"></td>
<td align="center">
<span class="FormData">3,359</span><span class="FootnoteData"><sup>(5)</sup></span>
</td>
<td align="center"><span class="FormData">A</span></td>
<td align="center">
<span class="FormText">$</span><span class="FormData">0</span>
</td>
<td align="center">
<span class="FormData">91,657</span><span class="FootnoteData"><sup>(3)</sup></span><span class="FootnoteData"><sup>(6)</sup></span>
</td>
<td align="center"><span class="FormData">D</span></td>
<td align="left"></td>
</tr>
<tr>
<td align="left"><span class="FormData">Common Stock</span></td>
<td align="center"><span class="FormData">02/19/2026</span></td>
<td align="center"></td>
<td align="center"><span class="SmallFormData">A</span></td>
<td align="center"></td>
<td align="center">
<span class="FormData">1,239</span><span class="FootnoteData"><sup>(7)</sup></span>
</td>
<td align="center"><span class="FormData">A</span></td>
<td align="center">
<span class="FormText">$</span><span class="FormData">0</span>
</td>
<td align="center">
<span class="FormData">92,896</span><span class="FootnoteData"><sup>(3)</sup></span><span class="FootnoteData"><sup>(6)</sup></span><span class="FootnoteData"><sup>(8)</sup></span>
</td>
<td align="center"><span class="FormData">D</span></td>
<td align="left"></td>
</tr>
<tr>
<td align="left"><span class="FormData">Common Stock</span></td>
<td align="center"><span class="FormData">02/19/2026</span></td>
<td align="center"></td>
<td align="center"><span class="SmallFormData">A</span></td>
<td align="center"></td>
<td align="center">
<span class="FormData">5,613</span><span class="FootnoteData"><sup>(9)</sup></span>
</td>
<td align="center"><span class="FormData">A</span></td>
<td align="center">
<span class="FormText">$</span><span class="FormData">0</span>
</td>
<td align="center">
<span class="FormData">98,509</span><span class="FootnoteData"><sup>(3)</sup></span><span class="FootnoteData"><sup>(6)</sup></span><span class="FootnoteData"><sup>(8)</sup></span>
</td>
<td align="center"><span class="FormData">D</span></td>
<td align="left"></td>
</tr>
<tr>
<td align="left"><span class="FormData">Common Stock</span></td>
<td align="center"><span class="FormData">02/19/2026</span></td>
<td align="center"></td>
<td align="center"><span class="SmallFormData">F</span></td>
<td align="center"></td>
<td align="center">
<span class="FormData">10,091</span><span class="FootnoteData"><sup>(10)</sup></span>
</td>
<td align="center"><span class="FormData">D</span></td>
<td align="center">
<span class="FormText">$</span><span class="FormData">31.125</span>
</td>
<td align="center">
<span class="FormData">88,418</span><span class="FootnoteData"><sup>(6)</sup></span><span class="FootnoteData"><sup>(8)</sup></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. Represents the number of shares of common stock resulting from Performance Share Units earned under the 2023-2025 Long Term Incentive Plan granted on 2/14/2023 upon certification of performance results by the Compensation Committee at 47.2% for the annual period ended December 31, 2025.</td></tr>
<tr><td class="FootnoteData">2. Includes 2,194 Performance Restricted Stock Units earned under the 2024-2026 Long Term Incentive Plan granted on 5/23/2024; those 2,194 Performance Restricted Stock Units will settle at the end of the performance period on December 31, 2026, upon certification by the Compensation Committee.</td></tr>
<tr><td class="FootnoteData">3. Includes 23,044 shares of common stock resulting from the settlement of Performance Restricted Stock Units earned under the 2023-2025 Long Term Incentive Plan granted on 2/14/2023; those 23,044 Performance Restricted Stock Units settled at the end of the 2023-2025 performance period upon certification by the Compensation Committee on 2/19/2026.</td></tr>
<tr><td class="FootnoteData">4. This amended Form 4 was filed to correct the number of shares beneficially owned to reflect the amendment made to the Form 4 originally filed on 2/18/2026.  The amendment to the Form 4 was filed on 3/09/2026 to correct the number of shares withheld to pay taxes applicable to the vesting of restricted stock on 2/14/2026.</td></tr>
<tr><td class="FootnoteData">5. Represents the number of Performance Restricted Stock Units earned under the 2024-2026 Long Term Incentive Plan granted on 5/23/2024 upon certification of performance results by the Compensation Committee at 39.5% for the annual period ended December 31, 2025.  The earned Performance Restricted Stock Units will settle at the end of the performance period on December 31, 2026, upon certification by the Compensation Committee.</td></tr>
<tr><td class="FootnoteData">6. Includes 5,553 Performance Restricted Stock Units earned under the 2024-2026 Long Term Incentive Plan granted on 5/23/2024; those 5,553 Performance Restricted Stock Units will settle at the end of the performance period on December 31, 2026, upon certification of the Compensation Committee.</td></tr>
<tr><td class="FootnoteData">7. Represents the number of Performance Restricted Stock Units earned under the 2025-2027 Long Term Incentive Plan granted on 5/22/2025 upon certification of performance results by the Compensation Committee at 11.2% for the annual period ended December 31, 2025.  The earned Performance Restricted Stock Units will settle at the end of the performance period on December 31, 2027, upon certification by the Compensation Committee.</td></tr>
<tr><td class="FootnoteData">8. Includes 1,239 Performance Restricted Stock Units earned under the 2025-2027 Long Term Incentive Plan granted on 5/22/2025; those 1,239 Performance Restricted Stock Units will settle at the end of the performance period on December 31, 2027, upon certification by the Compensation Committee.</td></tr>
<tr><td class="FootnoteData">9. Award of restricted stock units (RSUs), which are settled in stock upon vesting, and generally will vest ratably over a three-year period on the first, second, and third anniversary of the date of grant.</td></tr>
<tr><td class="FootnoteData">10. Shares withheld to pay taxes upon the vesting and settlement of all earned performance shares related to the 2023-2025 LTIP awarded on 2/14/2023.</td></tr>
<tr><td class="FormText"><b>Remarks:</b></td></tr>
<tr><td class="FootnoteData"></td></tr>
</table>
<table width="100%" border="0">
<tr>
<td width="60%"></td>
<td width="20%"><u><span class="FormData">/s/ Patrick J. Guinee by Judith Balog, attorney-in-fact</span></u></td>
<td width="20%"><u><span class="FormData">03/09/2026</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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