<?xml version="1.0" encoding="UTF-8"?><informationTable xmlns="http://www.sec.gov/edgar/document/thirteenf/informationtable" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><infoTable><nameOfIssuer>American Tower Corp</nameOfIssuer><titleOfClass>CL A</titleOfClass><cusip>03027X100</cusip><value>28215825</value><shrsOrPrnAmt><sshPrnamt>172500</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>172500</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Antero Resources Corp</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>03674X106</cusip><value>13177500</value><shrsOrPrnAmt><sshPrnamt>375000</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>375000</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Aptiv PLC</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>G3265R107</cusip><value>9207000</value><shrsOrPrnAmt><sshPrnamt>150000</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>150000</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Belden Inc</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>077454106</cusip><value>20957390</value><shrsOrPrnAmt><sshPrnamt>174776</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>174776</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>CECO Environmental Corp</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>125141101</cusip><value>56578840</value><shrsOrPrnAmt><sshPrnamt>623527</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>623527</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Devon Energy Corp</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>25179M103</cusip><value>20660000</value><shrsOrPrnAmt><sshPrnamt>500000</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>500000</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Forum Energy Technologies Inc</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>34984V209</cusip><value>10691958</value><shrsOrPrnAmt><sshPrnamt>212860</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>212860</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Manitowoc Co Inc/The</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>563571405</cusip><value>20559172</value><shrsOrPrnAmt><sshPrnamt>1480142</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>1480142</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Methode Electronics Inc</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>591520200</cusip><value>16423619</value><shrsOrPrnAmt><sshPrnamt>865768</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>865768</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Mistras Group Inc</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>60649T107</cusip><value>19640385</value><shrsOrPrnAmt><sshPrnamt>1124235</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>1124235</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Quanex Building Products Corp</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>747619104</cusip><value>20102208</value><shrsOrPrnAmt><sshPrnamt>1079603</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>1079603</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Range Resources Corp</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>75281A109</cusip><value>11970792</value><shrsOrPrnAmt><sshPrnamt>321882</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>321882</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Ranger Energy Services Inc</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>75282U104</cusip><value>33322574</value><shrsOrPrnAmt><sshPrnamt>2081360</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>2081360</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>RPC Inc</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>749660106</cusip><value>6450650</value><shrsOrPrnAmt><sshPrnamt>1106458</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>1106458</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Team Inc</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>878155308</cusip><value>1296035</value><shrsOrPrnAmt><sshPrnamt>75002</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>75002</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>TrueBlue Inc</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>89785X101</cusip><value>8962298</value><shrsOrPrnAmt><sshPrnamt>1285839</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>1285839</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable><infoTable><nameOfIssuer>Unisys Corp</nameOfIssuer><titleOfClass>COM</titleOfClass><cusip>909214306</cusip><value>12365361</value><shrsOrPrnAmt><sshPrnamt>3378514</sshPrnamt><sshPrnamtType>SH</sshPrnamtType></shrsOrPrnAmt><investmentDiscretion>SOLE</investmentDiscretion><votingAuthority><Sole>3378514</Sole><Shared>0</Shared><None>0</None></votingAuthority></infoTable></informationTable><!-- tableEntryCount=17 tableValueTotal=310581607 -->
