diff --git a/SimG4Core/Application/interface/CMSSimEventManager.h b/SimG4Core/Application/interface/CMSSimEventManager.h
index 334e995779702..aeb1e62095ba3 100644
--- a/SimG4Core/Application/interface/CMSSimEventManager.h
+++ b/SimG4Core/Application/interface/CMSSimEventManager.h
@@ -21,7 +21,7 @@ class G4Event;
 class EventAction;
 class StackingAction;
 class TrackingAction;
-class SteppingAction;
+class G4UserSteppingAction;
 class G4SDManager;
 class G4StateManager;
 class G4PrimaryTransformer;
@@ -44,7 +44,7 @@ class CMSSimEventManager {
   void SetUserAction(EventAction* ptr);
   void SetUserAction(StackingAction* ptr);
   void SetUserAction(TrackingAction* ptr);
-  void SetUserAction(SteppingAction* ptr);
+  void SetUserAction(G4UserSteppingAction* ptr);
 
   CMSSimEventManager(const CMSSimEventManager& right) = delete;
   CMSSimEventManager& operator=(const CMSSimEventManager& right) = delete;
diff --git a/SimG4Core/Application/interface/Phase2SteppingAction.h b/SimG4Core/Application/interface/Phase2SteppingAction.h
index 446474f826c2a..9599014fc3c89 100644
--- a/SimG4Core/Application/interface/Phase2SteppingAction.h
+++ b/SimG4Core/Application/interface/Phase2SteppingAction.h
@@ -3,6 +3,7 @@
 
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
 #include "SimG4Core/Notification/interface/SimActivityRegistry.h"
+#include "SimG4Core/Application/interface/SteppingTrackStatus.h"
 
 #include "G4LogicalVolume.hh"
 #include "G4Region.hh"
@@ -16,18 +17,6 @@
 
 class CMSSteppingVerbose;
 
-enum TrackStatus {
-  sAlive = 0,
-  sKilledByProcess = 1,
-  sDeadRegion = 2,
-  sOutOfTime = 3,
-  sLowEnergy = 4,
-  sLowEnergyInVacuum = 5,
-  sEnergyDepNaN = 6,
-  sVeryForward = 7,
-  sNumberOfSteps = 8
-};
-
 class Phase2SteppingAction : public G4UserSteppingAction {
 public:
   explicit Phase2SteppingAction(const CMSSteppingVerbose*, const edm::ParameterSet&, bool hasW);
diff --git a/SimG4Core/Application/interface/RunManagerMT.h b/SimG4Core/Application/interface/RunManagerMT.h
index 3c77481355473..f2481c3fafa18 100644
--- a/SimG4Core/Application/interface/RunManagerMT.h
+++ b/SimG4Core/Application/interface/RunManagerMT.h
@@ -77,6 +77,8 @@ class RunManagerMT {
   // need a non-const pointer. Thread-safety is handled inside Geant4.
   inline PhysicsList* physicsListForWorker() const { return m_physicsList.get(); }
 
+  inline bool isPhase2() const { return m_isPhase2; }
+
 private:
   void terminateRun();
 
@@ -84,6 +86,8 @@ class RunManagerMT {
 
   void setupVoxels();
 
+  void runForPhase2();
+
   G4MTRunManagerKernel* m_kernel;
 
   CustomUIsession* m_UIsession;
@@ -100,6 +104,7 @@ class RunManagerMT {
   bool m_StorePhysicsTables;
   bool m_RestorePhysicsTables;
   bool m_check;
+  bool m_isPhase2{false};
   edm::ParameterSet m_pPhysics;
   edm::ParameterSet m_pRunAction;
   edm::ParameterSet m_g4overlap;
diff --git a/SimG4Core/Application/interface/RunManagerMTWorker.h b/SimG4Core/Application/interface/RunManagerMTWorker.h
index a181483948ef3..bf424a76fb05a 100644
--- a/SimG4Core/Application/interface/RunManagerMTWorker.h
+++ b/SimG4Core/Application/interface/RunManagerMTWorker.h
@@ -35,6 +35,7 @@ class RunAction;
 class EventAction;
 class TrackingAction;
 class SteppingAction;
+class Phase2SteppingAction;
 class CMSSteppingVerbose;
 class CMSSimEventManager;
 class G4Field;
@@ -63,6 +64,7 @@ class RunManagerMTWorker {
   void Connect(EventAction*);
   void Connect(TrackingAction*);
   void Connect(SteppingAction*);
+  void Connect(Phase2SteppingAction*);
 
   SimTrackManager* GetSimTrackManager();
   std::vector<SensitiveTkDetector*>& sensTkDetectors();
@@ -99,6 +101,7 @@ class RunManagerMTWorker {
   bool m_LHCTransport{false};
   bool m_dumpMF{false};
   bool m_endOfRun{false};
+  bool m_isPhase2{false};
 
   const int m_thread_index{-1};
 
diff --git a/SimG4Core/Application/interface/SteppingAction.h b/SimG4Core/Application/interface/SteppingAction.h
index 89915845e997b..f6eb04ab3a9fd 100644
--- a/SimG4Core/Application/interface/SteppingAction.h
+++ b/SimG4Core/Application/interface/SteppingAction.h
@@ -3,6 +3,7 @@
 
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
 #include "SimG4Core/Notification/interface/SimActivityRegistry.h"
+#include "SimG4Core/Application/interface/SteppingTrackStatus.h"
 
 #include "G4LogicalVolume.hh"
 #include "G4Region.hh"
@@ -16,18 +17,6 @@
 
 class CMSSteppingVerbose;
 
-enum TrackStatus {
-  sAlive = 0,
-  sKilledByProcess = 1,
-  sDeadRegion = 2,
-  sOutOfTime = 3,
-  sLowEnergy = 4,
-  sLowEnergyInVacuum = 5,
-  sEnergyDepNaN = 6,
-  sVeryForward = 7,
-  sNumberOfSteps = 8
-};
-
 class SteppingAction : public G4UserSteppingAction {
 public:
   explicit SteppingAction(const CMSSteppingVerbose*, const edm::ParameterSet&, bool hasW);
@@ -48,7 +37,6 @@ class SteppingAction : public G4UserSteppingAction {
 
   const G4VPhysicalVolume* tracker{nullptr};
   const G4VPhysicalVolume* calo{nullptr};
-  const G4VPhysicalVolume* btl{nullptr};
   const CMSSteppingVerbose* steppingVerbose;
   double theCriticalEnergyForVacuum;
   double theCriticalDensity;
diff --git a/SimG4Core/Application/interface/SteppingTrackStatus.h b/SimG4Core/Application/interface/SteppingTrackStatus.h
new file mode 100644
index 0000000000000..fadef2f8cb1b2
--- /dev/null
+++ b/SimG4Core/Application/interface/SteppingTrackStatus.h
@@ -0,0 +1,16 @@
+#ifndef SimG4Core_SteppingTrackStatus_H
+#define SimG4Core_SteppingTrackStatus_H
+
+enum TrackStatus {
+  sAlive = 0,
+  sKilledByProcess = 1,
+  sDeadRegion = 2,
+  sOutOfTime = 3,
+  sLowEnergy = 4,
+  sLowEnergyInVacuum = 5,
+  sEnergyDepNaN = 6,
+  sVeryForward = 7,
+  sNumberOfSteps = 8
+};
+
+#endif
diff --git a/SimG4Core/Application/src/CMSSimEventManager.cc b/SimG4Core/Application/src/CMSSimEventManager.cc
index bd5962fb3b91d..21166b0fcfef4 100644
--- a/SimG4Core/Application/src/CMSSimEventManager.cc
+++ b/SimG4Core/Application/src/CMSSimEventManager.cc
@@ -3,7 +3,6 @@
 #include "SimG4Core/Application/interface/EventAction.h"
 #include "SimG4Core/Application/interface/StackingAction.h"
 #include "SimG4Core/Application/interface/TrackingAction.h"
-#include "SimG4Core/Application/interface/SteppingAction.h"
 
 #include "FWCore/ParameterSet/interface/ParameterSet.h"
 #include "FWCore/MessageLogger/interface/MessageLogger.h"
@@ -14,6 +13,7 @@
 #include "G4PrimaryTransformer.hh"
 #include "G4TrackingManager.hh"
 #include "G4TrackStatus.hh"
+#include "G4UserSteppingAction.hh"
 
 #include "G4SDManager.hh"
 #include "G4StateManager.hh"
@@ -107,6 +107,4 @@ void CMSSimEventManager::SetUserAction(TrackingAction* ptr) {
   m_defTrackManager->SetUserAction((G4UserTrackingAction*)ptr);
 }
 
-void CMSSimEventManager::SetUserAction(SteppingAction* ptr) {
-  m_defTrackManager->SetUserAction((G4UserSteppingAction*)ptr);
-}
+void CMSSimEventManager::SetUserAction(G4UserSteppingAction* ptr) { m_defTrackManager->SetUserAction(ptr); }
diff --git a/SimG4Core/Application/src/RunManagerMT.cc b/SimG4Core/Application/src/RunManagerMT.cc
index edc44244badaf..1322351d0cdfd 100644
--- a/SimG4Core/Application/src/RunManagerMT.cc
+++ b/SimG4Core/Application/src/RunManagerMT.cc
@@ -250,6 +250,7 @@ void RunManagerMT::initG4(const DDCompactView* pDD,
 
   // G4Region dump file name
   auto regionFile = m_p.getUntrackedParameter<std::string>("FileNameRegions", "");
+  runForPhase2();
 
   // Geometry checks
   if (m_check || !regionFile.empty()) {
@@ -357,3 +358,14 @@ void RunManagerMT::setupVoxels() {
   edm::LogVerbatim("SimG4CoreApplication")
       << "RunManagerMT: default voxel density=" << density << "; number of regions with special density " << nr;
 }
+
+void RunManagerMT::runForPhase2() {
+  const G4RegionStore* regStore = G4RegionStore::GetInstance();
+  for (auto& r : *regStore) {
+    const G4String& name = r->GetName();
+    if (name == "HGCalRegion" || name == "FastTimerRegionETL" || name == "FastTimerRegionBTL") {
+      m_isPhase2 = true;
+      break;
+    }
+  }
+}
diff --git a/SimG4Core/Application/src/RunManagerMTWorker.cc b/SimG4Core/Application/src/RunManagerMTWorker.cc
index c4bb6c944c2e1..3528a03d09918 100644
--- a/SimG4Core/Application/src/RunManagerMTWorker.cc
+++ b/SimG4Core/Application/src/RunManagerMTWorker.cc
@@ -6,6 +6,7 @@
 #include "SimG4Core/Application/interface/StackingAction.h"
 #include "SimG4Core/Application/interface/TrackingAction.h"
 #include "SimG4Core/Application/interface/SteppingAction.h"
+#include "SimG4Core/Application/interface/Phase2SteppingAction.h"
 #include "SimG4Core/Application/interface/CMSSimEventManager.h"
 #include "SimG4Core/Application/interface/CustomUIsessionThreadPrefix.h"
 #include "SimG4Core/Application/interface/CustomUIsessionToFile.h"
@@ -56,6 +57,7 @@
 #include "G4Field.hh"
 #include "G4FieldManager.hh"
 #include "G4ScoringManager.hh"
+#include "G4UserSteppingAction.hh"
 
 #include <atomic>
 #include <memory>
@@ -340,6 +342,7 @@ void RunManagerMTWorker::initializeG4(RunManagerMT* runManagerMaster, const edm:
 
   // Set the physics list for the worker, share from master
   PhysicsList* physicsList = runManagerMaster->physicsListForWorker();
+  m_isPhase2 = runManagerMaster->isPhase2();
 
   edm::LogVerbatim("SimG4CoreApplication")
       << "RunManagerMTWorker::InitializeG4: start initialisation of PhysicsList for the thread " << thisID;
@@ -415,8 +418,17 @@ void RunManagerMTWorker::initializeUserActions() {
     m_evtManager->SetUserAction(userTrackingAction);
   }
 
-  auto userSteppingAction = new SteppingAction(m_sVerbose.get(), m_pSteppingAction, m_hasWatchers);
-  Connect(userSteppingAction);
+  // different stepping actions for Run2,3 and Phase2
+  G4UserSteppingAction* userSteppingAction;
+  if (m_isPhase2) {
+    auto ptr = new Phase2SteppingAction(m_sVerbose.get(), m_pSteppingAction, m_hasWatchers);
+    Connect(ptr);
+    userSteppingAction = (G4UserSteppingAction*)ptr;
+  } else {
+    auto ptr = new SteppingAction(m_sVerbose.get(), m_pSteppingAction, m_hasWatchers);
+    Connect(ptr);
+    userSteppingAction = (G4UserSteppingAction*)ptr;
+  }
   if (m_UseG4EventManager) {
     eventManager->SetUserAction(userSteppingAction);
   } else {
@@ -450,6 +462,10 @@ void RunManagerMTWorker::Connect(SteppingAction* steppingAction) {
   steppingAction->m_g4StepSignal.connect(m_tls->registry->g4StepSignal_);
 }
 
+void RunManagerMTWorker::Connect(Phase2SteppingAction* steppingAction) {
+  steppingAction->m_g4StepSignal.connect(m_tls->registry->g4StepSignal_);
+}
+
 SimTrackManager* RunManagerMTWorker::GetSimTrackManager() {
   initializeTLS();
   return m_tls->trackManager.get();
diff --git a/SimG4Core/Application/src/SteppingAction.cc b/SimG4Core/Application/src/SteppingAction.cc
index c9ea781702bce..10b39543770e2 100644
--- a/SimG4Core/Application/src/SteppingAction.cc
+++ b/SimG4Core/Application/src/SteppingAction.cc
@@ -158,39 +158,10 @@ void SteppingAction::UserSteppingAction(const G4Step* aStep) {
       }
     }
   }
-  // check transition tracker/btl and tracker/calo
+  // check transition tracker/calo
   bool isKilled = false;
   if (sAlive == tstat || sVeryForward == tstat) {
-    // store TrackInformation about transition from one envelope to another
-    if (preStep->GetPhysicalVolume() == tracker && postStep->GetPhysicalVolume() == btl) {
-      // store transition tracker -> BTL only for tracks entering BTL for the first time
-      TrackInformation* trkinfo = static_cast<TrackInformation*>(theTrack->GetUserInformation());
-      if (!trkinfo->isFromTtoBTL() && !trkinfo->isFromBTLtoT()) {
-        trkinfo->setFromTtoBTL();
-        trkinfo->setIdAtBTLentrance(theTrack->GetTrackID());
-#ifdef DebugLog
-        LogDebug("SimG4CoreApplication") << "Setting flag for Tracker -> BTL " << trkinfo->isFromTtoBTL()
-                                         << " IdAtBTLentrance = " << trkinfo->idAtBTLentrance();
-#endif
-      } else {
-        trkinfo->setBTLlooper();
-        trkinfo->setIdAtBTLentrance(theTrack->GetTrackID());
-#ifdef DebugLog
-        LogDebug("SimG4CoreApplication") << "Setting flag for BTL looper " << trkinfo->isBTLlooper();
-        trkinfo->Print();
-#endif
-      }
-    } else if (preStep->GetPhysicalVolume() == btl && postStep->GetPhysicalVolume() == tracker) {
-      // store transition BTL -> tracker
-      TrackInformation* trkinfo = static_cast<TrackInformation*>(theTrack->GetUserInformation());
-      if (!trkinfo->isFromBTLtoT()) {
-        trkinfo->setFromBTLtoT();
-#ifdef DebugLog
-        LogDebug("SimG4CoreApplication") << "Setting flag for BTL -> Tracker " << trkinfo->isFromBTLtoT();
-#endif
-      }
-    } else if (preStep->GetPhysicalVolume() == tracker && postStep->GetPhysicalVolume() == calo) {
-      // store transition tracker -> calo
+    if (preStep->GetPhysicalVolume() == tracker && postStep->GetPhysicalVolume() == calo) {
       TrackInformation* trkinfo = static_cast<TrackInformation*>(theTrack->GetUserInformation());
       if (!trkinfo->crossedBoundary()) {
         trkinfo->setCrossedBoundary(theTrack);
@@ -233,14 +204,12 @@ bool SteppingAction::initPointer() {
       tracker = pvcite;
     } else if (pvname == "CALO" || pvname == "caloBase:CALO_1") {
       calo = pvcite;
-    } else if (pvname == "BarrelTimingLayer" || pvname == "btl:BarrelTimingLayer_1") {
-      btl = pvcite;
     }
-    if (tracker && calo && btl)
+    if (tracker && calo)
       break;
   }
   edm::LogVerbatim("SimG4CoreApplication")
-      << "SteppingAction: pointer for Tracker " << tracker << " and for Calo " << calo << " and for BTL " << btl;
+      << "SteppingAction: pointer for Tracker " << tracker << " and for Calo " << calo;
 
   const G4LogicalVolumeStore* lvs = G4LogicalVolumeStore::GetInstance();
   if (numberEkins > 0) {