diff --git a/src/classes/PMsr2Data.cpp b/src/classes/PMsr2Data.cpp
index b29db270..90752554 100644
--- a/src/classes/PMsr2Data.cpp
+++ b/src/classes/PMsr2Data.cpp
@@ -1705,8 +1705,7 @@ bool PMsr2Data::PrepareNewSortedInputFile(unsigned int tempRun) const
     tempParamName = msrParamList->at(l).fName.Data();
     std::string::size_type loc = tempParamName.rfind(tempRunNumber.str());
     if ( loc != std::string::npos ) {
-      tempParamName.erase(loc);
-      msrParamList->at(l).fName = tempParamName;
+      msrParamList->at(l).fName = StripRunNumberSuffix(tempParamName, tempRunNumber.str());
     } else {
       std::cerr << std::endl << ">> msr2data: **ERROR** The indices of the run specific parameters do not match the template run number!";
       std::cerr << std::endl << ">> msr2data: **ERROR** This should not happen! Please report a bug!";
@@ -2159,7 +2158,7 @@ int PMsr2Data::WriteOutput(const std::string &outfile, const std::vector<unsigne
             tempName = (*msrParamList)[fNumGlobalParam + fNumSpecParam*counter + i].fName.Data();
             std::string::size_type loc = tempName.rfind(curRunNumber.str());
             if (loc == tempName.length() - fRunNumberDigits) {
-              outFile << tempName.substr(0, loc) << std::endl;
+              outFile << StripRunNumberSuffix(tempName, curRunNumber.str()) << std::endl;
             } else {
               std::cerr << std::endl << ">> msr2data: **ERROR** The run index of some parameter does not match the run number being processed!";
               std::cerr << std::endl << ">> msr2data: **ERROR** The output will be flawed!";
@@ -2214,7 +2213,7 @@ int PMsr2Data::WriteOutput(const std::string &outfile, const std::vector<unsigne
             tempName = (*msrParamList)[fNumGlobalParam + fNumSpecParam*counter + i].fName.Data();
             std::string::size_type loc = tempName.rfind(curRunNumber.str());
             if (loc == tempName.length() - fRunNumberDigits) {
-              outFile << " " << tempName.substr(0, loc);
+              outFile << " " << StripRunNumberSuffix(tempName, curRunNumber.str());
             } else {
               std::cerr << std::endl << ">> msr2data: **ERROR** The run index of some parameter does not match the run number being processed!";
               std::cerr << std::endl << ">> msr2data: **ERROR** The output will be flawed!";
@@ -2291,7 +2290,7 @@ int PMsr2Data::WriteOutput(const std::string &outfile, const std::vector<unsigne
           tempName = (*msrParamList)[idx].fName.Data();
           std::string::size_type loc = tempName.rfind(curRunNumber.str());
           if (loc == tempName.length() - fRunNumberDigits) {
-            outFile << tempName.substr(0, loc) << " = ";
+            outFile << StripRunNumberSuffix(tempName, curRunNumber.str()) << " = ";
             if ((*msrParamList)[idx].fPosErrorPresent) {
               WriteValue(outFile, (*msrParamList)[idx].fValue, (*msrParamList)[idx].fPosError, outFile.width(), db);
               outFile << ", ";
@@ -2379,7 +2378,7 @@ int PMsr2Data::WriteOutput(const std::string &outfile, const std::vector<unsigne
           s = (*msrParamList)[idx].fName.Data();
           std::string::size_type loc = s.rfind(curRunNumber.str());
           if (loc == s.length() - fRunNumberDigits) {
-            length = s.length() - fRunNumberDigits;
+            length = StripRunNumberSuffix(s, curRunNumber.str()).length();
             if (length > maxlength)
               maxlength = length;
           } else {
@@ -2440,7 +2439,7 @@ int PMsr2Data::WriteOutput(const std::string &outfile, const std::vector<unsigne
             s = (*msrParamList)[idx].fName.Data();
             std::string::size_type loc = s.rfind(curRunNumber.str());
             if (loc == s.length() - fRunNumberDigits) {
-              s = s.substr(0, loc);
+              s = StripRunNumberSuffix(s, curRunNumber.str());
               outFile << std::setw(maxlength) << std::left << s \
                       << std::setw(maxlength + 6) << std::left << s + "PosErr" \
                       << std::setw(maxlength + 6) << std::left << s + "NegErr";
@@ -2745,6 +2744,30 @@ bool PMsr2Data::InParameterList(const unsigned int &paramValue, const std::vecto
   return false;
 }
 
+//-------------------------------------------------------------
+/**
+ * \brief Strips the trailing run-number suffix (and an optional preceding
+ *        separator such as '_') from a run-specific parameter name.
+ *
+ * \param name run-specific parameter name (e.g. "Asy_0420")
+ * \param runNumberStr zero-padded run number string used as suffix (e.g. "0420")
+ *
+ * \return the base parameter name with the run-number suffix (and its separator) removed,
+ *         or the unmodified name if it does not end in runNumberStr
+ */
+std::string PMsr2Data::StripRunNumberSuffix(const std::string &name, const std::string &runNumberStr) const
+{
+  if ((name.length() < runNumberStr.length()) ||
+      (name.compare(name.length() - runNumberStr.length(), runNumberStr.length(), runNumberStr)))
+    return name;
+
+  std::string::size_type loc(name.length() - runNumberStr.length());
+  if ((loc > 0) && (name[loc-1] == '_'))
+    --loc;
+
+  return name.substr(0, loc);
+}
+
 //-------------------------------------------------------------------------------------------------------
 // end
 //-------------------------------------------------------------------------------------------------------
diff --git a/src/include/PMsr2Data.h b/src/include/PMsr2Data.h
index a7ca3149..7d212089 100644
--- a/src/include/PMsr2Data.h
+++ b/src/include/PMsr2Data.h
@@ -298,6 +298,20 @@ class PMsr2Data
      */
     bool InParameterList(const unsigned int &paramValue, const std::vector<unsigned int>& paramList) const;
 
+    //-----------------------------------------------------------------------
+    /**
+     * \brief Strips the trailing run-number suffix (and an optional preceding
+     *        separator such as '_') from a run-specific parameter name.
+     *
+     * E.g. "alpha_ForwBackw_0139" with runNumberStr=="0139" becomes
+     * "alpha_ForwBackw" rather than "alpha_ForwBackw_".
+     *
+     * \param name run-specific parameter name (e.g. "Asy_0420")
+     * \param runNumberStr zero-padded run number string used as suffix (e.g. "0420")
+     * \return the base parameter name with the run-number suffix (and its separator) removed
+     */
+    std::string StripRunNumberSuffix(const std::string &name, const std::string &runNumberStr) const;
+
     std::string fFileExtension;                                 ///< File extension for data files (e.g., "bin", "root")
     std::vector<unsigned int> fRunVector;                       ///< Vector of run numbers to process
     mutable std::vector<unsigned int>::const_iterator fRunVectorIter; ///< Iterator for current position in run vector