diff --git a/include/tesseract/baseapi.h b/include/tesseract/baseapi.h
index 9caa729d..4fe5ca04 100644
--- a/include/tesseract/baseapi.h
+++ b/include/tesseract/baseapi.h
@@ -49,7 +49,9 @@ class UNICHARSET;
 
 class Dawg;
 class Dict;
+#ifndef DISABLED_LEGACY_ENGINE
 class EquationDetect;
+#endif // ndef DISABLED_LEGACY_ENGINE
 class PageIterator;
 class ImageThresholder;
 class LTRResultIterator;
@@ -766,7 +768,9 @@ protected:
 protected:
   Tesseract *tesseract_;          ///< The underlying data object.
   Tesseract *osd_tesseract_;      ///< For orientation & script detection.
+#ifndef DISABLED_LEGACY_ENGINE
   EquationDetect *equ_detect_;    ///< The equation detector.
+#endif // ndef DISABLED_LEGACY_ENGINE
   FileReader reader_;             ///< Reads files from any filesystem.
   ImageThresholder *thresholder_; ///< Image thresholding module.
   std::vector<ParagraphModel *> *paragraph_models_;
diff --git a/src/api/baseapi.cpp b/src/api/baseapi.cpp
index fe0040a8..572fee93 100644
--- a/src/api/baseapi.cpp
+++ b/src/api/baseapi.cpp
@@ -29,7 +29,9 @@
 #include "dict.h"       // for Dict
 #include "elst.h"       // for ELIST_ITERATOR, ELISTIZE, ELISTIZEH
 #include "environ.h"    // for l_uint8
+#ifndef DISABLED_LEGACY_ENGINE
 #include "equationdetect.h" // for EquationDetect, destructor of equ_detect_
+#endif // ndef DISABLED_LEGACY_ENGINE
 #include "errcode.h" // for ASSERT_HOST
 #include "helpers.h" // for IntCastRounded, chomp_string
 #include "host.h"    // for MAX_PATH
@@ -206,7 +208,9 @@ static void addAvailableLanguages(const std::string &datadir, const std::string
 TessBaseAPI::TessBaseAPI()
     : tesseract_(nullptr)
     , osd_tesseract_(nullptr)
+  #ifndef DISABLED_LEGACY_ENGINE
     , equ_detect_(nullptr)
+  #endif // ndef DISABLED_LEGACY_ENGINE
     , reader_(nullptr)
     ,
     // thresholder_ is initialized to nullptr here, but will be set before use
@@ -1889,15 +1893,17 @@ void TessBaseAPI::End() {
     delete paragraph_models_;
     paragraph_models_ = nullptr;
   }
+#ifndef DISABLED_LEGACY_ENGINE
   if (osd_tesseract_ == tesseract_) {
     osd_tesseract_ = nullptr;
   }
-  delete tesseract_;
-  tesseract_ = nullptr;
   delete osd_tesseract_;
   osd_tesseract_ = nullptr;
   delete equ_detect_;
   equ_detect_ = nullptr;
+#endif // ndef DISABLED_LEGACY_ENGINE
+  delete tesseract_;
+  tesseract_ = nullptr;
   input_file_.clear();
   output_file_.clear();
   datapath_.clear();
@@ -2119,6 +2125,7 @@ int TessBaseAPI::FindLines() {
 
   Tesseract *osd_tess = osd_tesseract_;
   OSResults osr;
+#ifndef DISABLED_LEGACY_ENGINE
   if (PSM_OSD_ENABLED(tesseract_->tessedit_pageseg_mode) && osd_tess == nullptr) {
     if (strcmp(language_.c_str(), "osd") == 0) {
       osd_tess = tesseract_;
@@ -2144,6 +2151,7 @@ int TessBaseAPI::FindLines() {
       }
     }
   }
+#endif // ndef DISABLED_LEGACY_ENGINE
 
   if (tesseract_->SegmentPage(input_file_.c_str(), block_list_, osd_tess, &osr) < 0) {
     return -1;
diff --git a/src/ccmain/tesseractclass.cpp b/src/ccmain/tesseractclass.cpp
index a8cbcd3d..8f9f451f 100644
--- a/src/ccmain/tesseractclass.cpp
+++ b/src/ccmain/tesseractclass.cpp
@@ -400,7 +400,9 @@ Tesseract::Tesseract()
                        "instance is not going to be used for OCR but say only "
                        "for layout analysis.",
                        this->params())
+#ifndef DISABLED_LEGACY_ENGINE
     , BOOL_MEMBER(textord_equation_detect, false, "Turn on equation detector", this->params())
+#endif // ndef DISABLED_LEGACY_ENGINE
     , BOOL_MEMBER(textord_tabfind_vertical_text, true, "Enable vertical detection", this->params())
     , BOOL_MEMBER(textord_tabfind_force_vertical_text, false, "Force using vertical text page mode",
                   this->params())
@@ -452,7 +454,9 @@ Tesseract::Tesseract()
     , reskew_(1.0f, 0.0f)
     , most_recently_used_(this)
     , font_table_size_(0)
+#ifndef DISABLED_LEGACY_ENGINE
     , equ_detect_(nullptr)
+#endif // ndef DISABLED_LEGACY_ENGINE
     , lstm_recognizer_(nullptr)
     , train_line_page_num_(0) {}
 
diff --git a/src/ccmain/tesseractclass.h b/src/ccmain/tesseractclass.h
index b5753bef..94681ab6 100644
--- a/src/ccmain/tesseractclass.h
+++ b/src/ccmain/tesseractclass.h
@@ -69,7 +69,9 @@ class WERD_RES;
 
 class ColumnFinder;
 class DocumentData;
+#ifndef DISABLED_LEGACY_ENGINE
 class EquationDetect;
+#endif // ndef DISABLED_LEGACY_ENGINE
 class ImageData;
 class LSTMRecognizer;
 class Tesseract;
@@ -189,8 +191,10 @@ public:
   // Clear the document dictionary for this and all subclassifiers.
   void ResetDocumentDictionary();
 
+#ifndef DISABLED_LEGACY_ENGINE
   // Set the equation detector.
   void SetEquationDetect(EquationDetect *detector);
+#endif // ndef DISABLED_LEGACY_ENGINE
 
   // Simple accessors.
   const FCOORD &reskew() const {
@@ -942,7 +946,9 @@ public:
   BOOL_VAR_H(textord_use_cjk_fp_model);
   BOOL_VAR_H(poly_allow_detailed_fx);
   BOOL_VAR_H(tessedit_init_config_only);
+#ifndef DISABLED_LEGACY_ENGINE
   BOOL_VAR_H(textord_equation_detect);
+#endif // ndef DISABLED_LEGACY_ENGINE
   BOOL_VAR_H(textord_tabfind_vertical_text);
   BOOL_VAR_H(textord_tabfind_force_vertical_text);
   double_VAR_H(textord_tabfind_vertical_text_ratio);
@@ -1001,8 +1007,10 @@ private:
   Tesseract *most_recently_used_;
   // The size of the font table, ie max possible font id + 1.
   int font_table_size_;
+#ifndef DISABLED_LEGACY_ENGINE
   // Equation detector. Note: this pointer is NOT owned by the class.
   EquationDetect *equ_detect_;
+#endif // ndef DISABLED_LEGACY_ENGINE
   // LSTM recognizer, if available.
   LSTMRecognizer *lstm_recognizer_;
   // Output "page" number (actually line number) using TrainLineRecognizer.