diff --git a/packages/tempus/src/Tempus_RKButcherTableau.hpp b/packages/tempus/src/Tempus_RKButcherTableau.hpp
index c8950af3f2d1..ad2bf2cda0f5 100644
--- a/packages/tempus/src/Tempus_RKButcherTableau.hpp
+++ b/packages/tempus/src/Tempus_RKButcherTableau.hpp
@@ -171,6 +171,39 @@ class RKButcherTableau :
       }
     //@}
 
+    bool operator == (const RKButcherTableau & t) const {
+      const Scalar relTol = 1.0e-15;
+      if ( A_->numRows() != t.A_->numRows() ||
+           A_->numCols() != t.A_->numCols()    ) {
+        return false;
+      } else {
+        int i, j;
+        for(i = 0; i < A_->numRows(); i++) {
+          for(j = 0; j < A_->numCols(); j++) {
+            if(std::abs((t.A_(i,j) - A_(i,j))/A_(i,j)) > relTol) return false;
+          }
+        }
+      }
+
+      if ( b_->length() != t.b_->length() ||
+           b_->length() != t.c_->length() ||
+           b_->length() != t.bstar_->length() ) {
+        return false;
+      } else {
+        int i;
+        for(i = 0; i < A_->numRows(); i++) {
+          if(std::abs((t.b_(i) - b_(i))/b_(i)) > relTol) return false;
+          if(std::abs((t.c_(i) - c_(i))/c_(i)) > relTol) return false;
+          if(std::abs((t.bstar_(i) - bstar_(i))/bstar_(i)) > relTol) return false;
+        }
+      }
+      return true;
+    }
+
+    bool operator != (const RKButcherTableau & t) const {
+      return !((*this) == t);
+    }
+
   private:
 
     RKButcherTableau();
diff --git a/packages/tempus/src/Tempus_StepperDIRK_decl.hpp b/packages/tempus/src/Tempus_StepperDIRK_decl.hpp
index 588d26638213..37928615a5a9 100644
--- a/packages/tempus/src/Tempus_StepperDIRK_decl.hpp
+++ b/packages/tempus/src/Tempus_StepperDIRK_decl.hpp
@@ -11,7 +11,6 @@
 
 #include "Tempus_config.hpp"
 #include "Tempus_StepperRKBase.hpp"
-#include "Tempus_RKButcherTableau.hpp"
 #include "Tempus_StepperImplicit.hpp"
 #include "Tempus_WrapperModelEvaluator.hpp"
 #ifndef TEMPUS_HIDE_DEPRECATED_CODE
@@ -165,9 +164,6 @@ class StepperDIRK : virtual public Tempus::StepperImplicit<Scalar>,
     virtual Teuchos::RCP<StepperObserver<Scalar> > getObserver() const
     { return this->stepperObserver_; }
 #endif
-    virtual Teuchos::RCP<const RKButcherTableau<Scalar> > getTableau()
-    { return tableau_; }
-
     /// Initialize after construction and changing input parameters.
     virtual void initialize();
 
@@ -187,14 +183,11 @@ class StepperDIRK : virtual public Tempus::StepperImplicit<Scalar>,
 
     /// Get a default (initial) StepperState
     virtual Teuchos::RCP<Tempus::StepperState<Scalar> >getDefaultStepperState();
-    virtual Scalar getOrder()    const{return tableau_->order();}
-    virtual Scalar getOrderMin() const{return tableau_->orderMin();}
-    virtual Scalar getOrderMax() const{return tableau_->orderMax();}
 
     virtual bool isExplicit() const
     {
-      const int numStages = tableau_->numStages();
-      Teuchos::SerialDenseMatrix<int,Scalar> A = tableau_->A();
+      const int numStages = this->tableau_->numStages();
+      Teuchos::SerialDenseMatrix<int,Scalar> A = this->tableau_->A();
       bool isExplicit = false;
       for (int i=0; i<numStages; ++i) if (A(i,i) == 0.0) isExplicit = true;
       return isExplicit;
@@ -219,7 +212,7 @@ class StepperDIRK : virtual public Tempus::StepperImplicit<Scalar>,
   /// Return alpha = d(xDot)/dx.
   virtual Scalar getAlpha(const Scalar dt) const
   {
-    const Teuchos::SerialDenseMatrix<int,Scalar> & A=tableau_->A();
+    const Teuchos::SerialDenseMatrix<int,Scalar> & A=this->tableau_->A();
     return Scalar(1.0)/(dt*A(0,0));  // Getting the first diagonal coeff!
   }
   /// Return beta  = d(x)/dx.
@@ -273,8 +266,6 @@ class StepperDIRK : virtual public Tempus::StepperImplicit<Scalar>,
 
   virtual void setupTableau() = 0;
 
-  Teuchos::RCP<RKButcherTableau<Scalar> >                tableau_;
-
   std::vector<Teuchos::RCP<Thyra::VectorBase<Scalar> > > stageXDot_;
   Teuchos::RCP<Thyra::VectorBase<Scalar> >               xTilde_;
 
diff --git a/packages/tempus/src/Tempus_StepperDIRK_impl.hpp b/packages/tempus/src/Tempus_StepperDIRK_impl.hpp
index ea9fc9bbcfd8..a7b09d42299e 100644
--- a/packages/tempus/src/Tempus_StepperDIRK_impl.hpp
+++ b/packages/tempus/src/Tempus_StepperDIRK_impl.hpp
@@ -160,7 +160,7 @@ template<class Scalar>
 void StepperDIRK<Scalar>::initialize()
 {
   // Initialize the stage vectors
-  const int numStages = tableau_->numStages();
+  const int numStages = this->tableau_->numStages();
   this->stageX_    = this->wrapperModel_->getNominalValues().get_x()->clone_v();
   stageXDot_.resize(numStages);
   for (int i=0; i<numStages; ++i) {
@@ -170,7 +170,7 @@ void StepperDIRK<Scalar>::initialize()
   xTilde_    = Thyra::createMember(this->wrapperModel_->get_x_space());
   assign(xTilde_.ptr(),    Teuchos::ScalarTraits<Scalar>::zero());
 
-  if (tableau_->isEmbedded() and this->getUseEmbedded()) {
+  if (this->tableau_->isEmbedded() and this->getUseEmbedded()) {
     ee_    = Thyra::createMember(this->wrapperModel_->get_f_space());
     abs_u0 = Thyra::createMember(this->wrapperModel_->get_f_space());
     abs_u  = Thyra::createMember(this->wrapperModel_->get_f_space());
@@ -227,10 +227,10 @@ void StepperDIRK<Scalar>::takeStep(
     const Scalar dt = workingState->getTimeStep();
     const Scalar time = currentState->getTime();
 
-    const int numStages = tableau_->numStages();
-    Teuchos::SerialDenseMatrix<int,Scalar> A = tableau_->A();
-    Teuchos::SerialDenseVector<int,Scalar> b = tableau_->b();
-    Teuchos::SerialDenseVector<int,Scalar> c = tableau_->c();
+    const int numStages = this->tableau_->numStages();
+    Teuchos::SerialDenseMatrix<int,Scalar> A = this->tableau_->A();
+    Teuchos::SerialDenseVector<int,Scalar> b = this->tableau_->b();
+    Teuchos::SerialDenseVector<int,Scalar> c = this->tableau_->c();
 
     // Reset non-zero initial guess.
     if ( this->getResetInitialGuess() && (!this->getZeroInitialGuess()) )
@@ -253,8 +253,8 @@ void StepperDIRK<Scalar>::takeStep(
       bool isNeeded = false;
       for (int k=i+1; k<numStages; ++k) if (A(k,i) != 0.0) isNeeded = true;
       if (b(i) != 0.0) isNeeded = true;
-      if (tableau_->isEmbedded() && this->getUseEmbedded() &&
-          tableau_->bstar()(i) != 0.0)
+      if (this->tableau_->isEmbedded() && this->getUseEmbedded() &&
+          this->tableau_->bstar()(i) != 0.0)
         isNeeded = true;
       if (isNeeded == false) {
         assign(stageXDot_[i].ptr(), Teuchos::ScalarTraits<Scalar>::zero());
@@ -344,14 +344,14 @@ void StepperDIRK<Scalar>::takeStep(
       }
     }
 
-    if (tableau_->isEmbedded() and this->getUseEmbedded()) {
+    if (this->tableau_->isEmbedded() and this->getUseEmbedded()) {
       const Scalar tolRel = workingState->getTolRel();
       const Scalar tolAbs = workingState->getTolAbs();
 
       // just compute the error weight vector
       // (all that is needed is the error, and not the embedded solution)
       Teuchos::SerialDenseVector<int,Scalar> errWght = b ;
-      errWght -= tableau_->bstar();
+      errWght -= this->tableau_->bstar();
 
       // compute local truncation error estimate: | u^{n+1} - \hat{u}^{n+1} |
       // Sum for solution: ee_n = Sum{ (b(i) - bstar(i)) * dt*f(i) }
@@ -422,8 +422,8 @@ void StepperDIRK<Scalar>::describe(
   StepperImplicit<Scalar>::describe(out, verbLevel);
 
   out << "--- StepperDIRK ---\n";
-  out << "  tableau_            = " << tableau_ << std::endl;
-  if (tableau_ != Teuchos::null) tableau_->describe(out, verbLevel);
+  out << "  tableau_            = " << this->tableau_ << std::endl;
+  if (this->tableau_ != Teuchos::null) this->tableau_->describe(out, verbLevel);
 #ifndef TEMPUS_HIDE_DEPRECATED_CODE
   out << "  stepperObserver_    = " << stepperObserver_ << std::endl;
 #endif
@@ -452,7 +452,7 @@ bool StepperDIRK<Scalar>::isValidSetup(Teuchos::FancyOStream & out) const
   if ( !Stepper<Scalar>::isValidSetup(out) ) isValidSetup = false;
   if ( !StepperImplicit<Scalar>::isValidSetup(out) ) isValidSetup = false;
 
-  if (tableau_ == Teuchos::null) {
+  if (this->tableau_ == Teuchos::null) {
     isValidSetup = false;
     out << "The tableau is not set!\n";
   }
diff --git a/packages/tempus/src/Tempus_StepperExplicitRK_decl.hpp b/packages/tempus/src/Tempus_StepperExplicitRK_decl.hpp
index 58c5c832290d..a5c12f587f1a 100644
--- a/packages/tempus/src/Tempus_StepperExplicitRK_decl.hpp
+++ b/packages/tempus/src/Tempus_StepperExplicitRK_decl.hpp
@@ -12,7 +12,6 @@
 #include "Tempus_config.hpp"
 #include "Tempus_StepperRKBase.hpp"
 #include "Tempus_StepperExplicit.hpp"
-#include "Tempus_RKButcherTableau.hpp"
 #ifndef TEMPUS_HIDE_DEPRECATED_CODE
   #include "Tempus_StepperRKObserverComposite.hpp"
 #endif
@@ -111,9 +110,6 @@ class StepperExplicitRK : virtual public Tempus::StepperExplicit<Scalar>,
     virtual Teuchos::RCP<StepperObserver<Scalar> > getObserver() const
     { return this->stepperObserver_; }
 #endif
-    virtual Teuchos::RCP<const RKButcherTableau<Scalar> > getTableau()
-    { return tableau_; }
-
     /// Initialize during construction and after changing input parameters.
     virtual void initialize();
 
@@ -127,9 +123,6 @@ class StepperExplicitRK : virtual public Tempus::StepperExplicit<Scalar>,
 
     /// Get a default (initial) StepperState
     virtual Teuchos::RCP<Tempus::StepperState<Scalar> > getDefaultStepperState();
-    virtual Scalar getOrder() const {return tableau_->order();}
-    virtual Scalar getOrderMin() const {return tableau_->orderMin();}
-    virtual Scalar getOrderMax() const {return tableau_->orderMax();}
     virtual Scalar getInitTimeStep(
         const Teuchos::RCP<SolutionHistory<Scalar> >& solutionHistory) const;
 
@@ -191,8 +184,6 @@ class StepperExplicitRK : virtual public Tempus::StepperExplicit<Scalar>,
   virtual void setupTableau() = 0;
 
 
-  Teuchos::RCP<RKButcherTableau<Scalar> >                tableau_;
-
   std::vector<Teuchos::RCP<Thyra::VectorBase<Scalar> > > stageXDot_;
 
 #ifndef TEMPUS_HIDE_DEPRECATED_CODE
diff --git a/packages/tempus/src/Tempus_StepperExplicitRK_impl.hpp b/packages/tempus/src/Tempus_StepperExplicitRK_impl.hpp
index 74294b5d9660..9ebe0b8c9d6b 100644
--- a/packages/tempus/src/Tempus_StepperExplicitRK_impl.hpp
+++ b/packages/tempus/src/Tempus_StepperExplicitRK_impl.hpp
@@ -222,7 +222,7 @@ void StepperExplicitRK<Scalar>::setObserver(
 template<class Scalar>
 void StepperExplicitRK<Scalar>::initialize()
 {
-  TEUCHOS_TEST_FOR_EXCEPTION( tableau_ == Teuchos::null, std::logic_error,
+  TEUCHOS_TEST_FOR_EXCEPTION( this->tableau_ == Teuchos::null, std::logic_error,
     "Error - Need to set the tableau, before calling "
     "StepperExplicitRK::initialize()\n");
 
@@ -231,14 +231,14 @@ void StepperExplicitRK<Scalar>::initialize()
     "StepperExplicitRK::initialize()\n");
 
   // Initialize the stage vectors
-  int numStages = tableau_->numStages();
+  int numStages = this->tableau_->numStages();
   stageXDot_.resize(numStages);
   for (int i=0; i<numStages; ++i) {
     stageXDot_[i] = Thyra::createMember(this->appModel_->get_f_space());
     assign(stageXDot_[i].ptr(), Teuchos::ScalarTraits<Scalar>::zero());
   }
 
-  if ( tableau_->isEmbedded() and this->getUseEmbedded() ){
+  if ( this->tableau_->isEmbedded() and this->getUseEmbedded() ){
      ee_ = Thyra::createMember(this->appModel_->get_f_space());
      abs_u0 = Thyra::createMember(this->appModel_->get_f_space());
      abs_u = Thyra::createMember(this->appModel_->get_f_space());
@@ -295,10 +295,10 @@ void StepperExplicitRK<Scalar>::takeStep(
     const Scalar dt = workingState->getTimeStep();
     const Scalar time = currentState->getTime();
 
-    const int numStages = tableau_->numStages();
-    Teuchos::SerialDenseMatrix<int,Scalar> A = tableau_->A();
-    Teuchos::SerialDenseVector<int,Scalar> b = tableau_->b();
-    Teuchos::SerialDenseVector<int,Scalar> c = tableau_->c();
+    const int numStages = this->tableau_->numStages();
+    Teuchos::SerialDenseMatrix<int,Scalar> A = this->tableau_->A();
+    Teuchos::SerialDenseVector<int,Scalar> b = this->tableau_->b();
+    Teuchos::SerialDenseVector<int,Scalar> c = this->tableau_->c();
 
     this->stageX_ = workingState->getX();
     Thyra::assign(this->stageX_.ptr(), *(currentState->getX()));
@@ -376,7 +376,7 @@ void StepperExplicitRK<Scalar>::takeStep(
     // can change the step status
     workingState->setSolutionStatus(Status::PASSED);
 
-    if (tableau_->isEmbedded() and this->getUseEmbedded()) {
+    if (this->tableau_->isEmbedded() and this->getUseEmbedded()) {
 
       const Scalar tolRel = workingState->getTolRel();
       const Scalar tolAbs = workingState->getTolAbs();
@@ -384,7 +384,7 @@ void StepperExplicitRK<Scalar>::takeStep(
       // just compute the error weight vector
       // (all that is needed is the error, and not the embedded solution)
       Teuchos::SerialDenseVector<int,Scalar> errWght = b ;
-      errWght -= tableau_->bstar();
+      errWght -= this->tableau_->bstar();
 
       //compute local truncation error estimate: | u^{n+1} - \hat{u}^{n+1} |
       // Sum for solution: ee_n = Sum{ (b(i) - bstar(i)) * dt*f(i) }
@@ -452,8 +452,8 @@ void StepperExplicitRK<Scalar>::describe(
   StepperExplicit<Scalar>::describe(out, verbLevel);
 
   out << "--- StepperExplicitRK ---\n";
-  if (tableau_ != Teuchos::null) tableau_->describe(out, verbLevel);
-  out << "  tableau_           = " << tableau_ << std::endl;
+  if (this->tableau_ != Teuchos::null) this->tableau_->describe(out, verbLevel);
+  out << "  tableau_           = " << this->tableau_ << std::endl;
 #ifndef TEMPUS_HIDE_DEPRECATED_CODE
   out << "  stepperObserver_   = " << stepperObserver_ << std::endl;
 #endif
@@ -481,7 +481,7 @@ bool StepperExplicitRK<Scalar>::isValidSetup(Teuchos::FancyOStream & out) const
   if ( !Stepper<Scalar>::isValidSetup(out) ) isValidSetup = false;
   if ( !StepperExplicit<Scalar>::isValidSetup(out) ) isValidSetup = false;
 
-  if (tableau_ == Teuchos::null) {
+  if (this->tableau_ == Teuchos::null) {
     isValidSetup = false;
     out << "The tableau is not set!\n";
   }
diff --git a/packages/tempus/src/Tempus_StepperIMEX_RK_Partition_decl.hpp b/packages/tempus/src/Tempus_StepperIMEX_RK_Partition_decl.hpp
index 8a9b1c2e8c44..f76d789a72ec 100644
--- a/packages/tempus/src/Tempus_StepperIMEX_RK_Partition_decl.hpp
+++ b/packages/tempus/src/Tempus_StepperIMEX_RK_Partition_decl.hpp
@@ -356,15 +356,27 @@ class StepperIMEX_RK_Partition : virtual public Tempus::StepperImplicit<Scalar>,
 
   /// \name Basic stepper methods
   //@{
+    /// Returns the explicit tableau!
+    virtual Teuchos::RCP<const RKButcherTableau<Scalar> > getTableau() const
+    { return getExplicitTableau(); }
+
     /// Set both the explicit and implicit tableau from ParameterList
     virtual void setTableaus(std::string stepperType = "",
       Teuchos::RCP<const RKButcherTableau<Scalar> > explicitTableau = Teuchos::null,
       Teuchos::RCP<const RKButcherTableau<Scalar> > implicitTableau = Teuchos::null);
 
+    /// Return explicit tableau.
+    virtual Teuchos::RCP<const RKButcherTableau<Scalar> > getExplicitTableau() const
+    { return explicitTableau_; }
+
     /// Set the explicit tableau from tableau
     virtual void setExplicitTableau(
       Teuchos::RCP<const RKButcherTableau<Scalar> > explicitTableau);
 
+    /// Return implicit tableau.
+    virtual Teuchos::RCP<const RKButcherTableau<Scalar> > getImplicitTableau() const
+    { return implicitTableau_; }
+
     /// Set the implicit tableau from tableau
     virtual void setImplicitTableau(
       Teuchos::RCP<const RKButcherTableau<Scalar> > implicitTableau);
@@ -417,7 +429,10 @@ class StepperIMEX_RK_Partition : virtual public Tempus::StepperImplicit<Scalar>,
     virtual OrderODE getOrderODE()   const {return FIRST_ORDER_ODE;}
   //@}
 
-  Teuchos::RCP<Thyra::VectorBase<Scalar> >& getStageZ() {return stageZ_;};
+  /// Return the full stage solution which is Z (the concat of X and Y) for IMEX Partition.
+  Teuchos::RCP<Thyra::VectorBase<Scalar> > getStageX() {return stageZ_;}
+  /// Explicitly return the full stage solution, Z.
+  Teuchos::RCP<Thyra::VectorBase<Scalar> > getStageZ() {return stageZ_;};
   std::vector<Teuchos::RCP<Thyra::VectorBase<Scalar> > >& getStageF() {return stageF_;};
   std::vector<Teuchos::RCP<Thyra::VectorBase<Scalar> > >& getStageGx() {return stageGx_;};
   Teuchos::RCP<Thyra::VectorBase<Scalar> >& getXTilde() {return xTilde_;};
diff --git a/packages/tempus/src/Tempus_StepperIMEX_RK_decl.hpp b/packages/tempus/src/Tempus_StepperIMEX_RK_decl.hpp
index 2ac4c7c64200..2e1808ace6a9 100644
--- a/packages/tempus/src/Tempus_StepperIMEX_RK_decl.hpp
+++ b/packages/tempus/src/Tempus_StepperIMEX_RK_decl.hpp
@@ -326,15 +326,27 @@ class StepperIMEX_RK : virtual public Tempus::StepperImplicit<Scalar>,
 
   /// \name Basic stepper methods
   //@{
+    /// Returns the explicit tableau!
+    virtual Teuchos::RCP<const RKButcherTableau<Scalar> > getTableau() const
+    { return getExplicitTableau(); }
+
     /// Set both the explicit and implicit tableau from ParameterList
     virtual void setTableaus( std::string stepperType = "",
       Teuchos::RCP<const RKButcherTableau<Scalar> > explicitTableau = Teuchos::null,
       Teuchos::RCP<const RKButcherTableau<Scalar> > implicitTableau = Teuchos::null);
 
+    /// Return explicit tableau.
+    virtual Teuchos::RCP<const RKButcherTableau<Scalar> > getExplicitTableau() const
+    { return explicitTableau_; }
+
     /// Set the explicit tableau from tableau
     virtual void setExplicitTableau(
       Teuchos::RCP<const RKButcherTableau<Scalar> > explicitTableau);
 
+    /// Return implicit tableau.
+    virtual Teuchos::RCP<const RKButcherTableau<Scalar> > getImplicitTableau() const
+    { return implicitTableau_; }
+
     /// Set the implicit tableau from tableau
     virtual void setImplicitTableau(
       Teuchos::RCP<const RKButcherTableau<Scalar> > implicitTableau);
diff --git a/packages/tempus/src/Tempus_StepperRKAppActionComposite.hpp b/packages/tempus/src/Tempus_StepperRKAppActionComposite.hpp
index d3f81bbfce06..4841faa17e1a 100644
--- a/packages/tempus/src/Tempus_StepperRKAppActionComposite.hpp
+++ b/packages/tempus/src/Tempus_StepperRKAppActionComposite.hpp
@@ -10,7 +10,6 @@
 #define Tempus_StepperRKAppActionComposite_hpp
 
 #include "Tempus_StepperRKAppAction.hpp"
-#include "Tempus_TimeStepControl.hpp"
 #include <vector>
 
 namespace Tempus {
@@ -27,15 +26,15 @@ class StepperRKAppActionComposite
 public:
 
   /// Default constructor
-  StepperRKAppActionComposite();
+  StepperRKAppActionComposite() {}
 
   /// Destructor
-  virtual ~StepperRKAppActionComposite();
+  virtual ~StepperRKAppActionComposite() {}
 
   /// Execute application action for RK Stepper.
   virtual void execute(
     Teuchos::RCP<SolutionHistory<Scalar> > sh,
-    Teuchos::RCP<StepperRK<Scalar> > stepper,
+    Teuchos::RCP<StepperRKBase<Scalar> > stepper,
     const typename StepperRKAppAction<Scalar>::ACTION_LOCATION actLoc)
   {
     for(auto& a : appActions_)
@@ -43,13 +42,13 @@ class StepperRKAppActionComposite
   }
 
   // Add AppAction to the AppAction vector.
-  void addRKAppAction(Teuchos::RCP<StepperRKAppAction<Scalar> > appAction);
+  void addRKAppAction(Teuchos::RCP<StepperRKAppAction<Scalar> > appAction)
   {
     appActions_.push_back(appAction);
   }
 
   // Clear the AppAction vector.
-  void clearRKAppActions();
+  void clearRKAppActions()
   { appActions_.clear(); }
 
   // Return the size of the AppAction vector.
diff --git a/packages/tempus/src/Tempus_StepperRKBase.hpp b/packages/tempus/src/Tempus_StepperRKBase.hpp
index 3f15bec1e81a..832c55e714ea 100644
--- a/packages/tempus/src/Tempus_StepperRKBase.hpp
+++ b/packages/tempus/src/Tempus_StepperRKBase.hpp
@@ -12,6 +12,7 @@
 #include "Thyra_VectorBase.hpp"
 
 #include "Tempus_Stepper.hpp"
+#include "Tempus_RKButcherTableau.hpp"
 #include "Tempus_StepperRKAppAction.hpp"
 #include "Tempus_StepperRKModifierDefault.hpp"
 
@@ -30,11 +31,19 @@ class StepperRKBase : virtual public Tempus::Stepper<Scalar>
 
 public:
 
-  virtual int getStageNumber() const { return stageNumber_; }
+  virtual Teuchos::RCP<const RKButcherTableau<Scalar> > getTableau() const
+  { return tableau_; }
+
+  virtual Scalar getOrder()    const{return getTableau()->order();}
+  virtual Scalar getOrderMin() const{return getTableau()->orderMin();}
+  virtual Scalar getOrderMax() const{return getTableau()->orderMax();}
+  virtual int getNumberOfStages() const {return getTableau()->numStages();}
 
+  virtual int getStageNumber() const { return stageNumber_; }
   virtual void setStageNumber(int s) { stageNumber_ = s; }
 
   virtual Teuchos::RCP<Thyra::VectorBase<Scalar> > getStageX() {return stageX_;}
+  virtual Teuchos::RCP<const Thyra::VectorBase<Scalar> > getStageX() const  {return stageX_;}
 
   virtual void setAppAction(Teuchos::RCP<StepperRKAppAction<Scalar> > appAction)
   {
@@ -53,7 +62,10 @@ class StepperRKBase : virtual public Tempus::Stepper<Scalar>
 
 protected:
 
-  int stageNumber_;    //< The Runge-Kutta stage number, {0,...,s-1}.
+  Teuchos::RCP<RKButcherTableau<Scalar> >   tableau_;
+
+  /// The current Runge-Kutta stage number, {0,...,s-1}.  -1 indicates outside stage loop.
+  int stageNumber_;
   Teuchos::RCP<Thyra::VectorBase<Scalar> >  stageX_;
   Teuchos::RCP<StepperRKAppAction<Scalar> > stepperRKAppAction_;
 
diff --git a/packages/tempus/src/Tempus_StepperRKButcherTableau.hpp b/packages/tempus/src/Tempus_StepperRKButcherTableau.hpp
index f33e97f7f3ad..aa2d2b4b02bb 100644
--- a/packages/tempus/src/Tempus_StepperRKButcherTableau.hpp
+++ b/packages/tempus/src/Tempus_StepperRKButcherTableau.hpp
@@ -4055,7 +4055,7 @@ class StepperSDIRK_5Stage4thOrder :
       << "        [ 371/1360  -137/2720  15/544  1/4         ]\n"
       << "        [ 25/24     -49/48     125/16  -85/12  1/4 ]\n"
       << "b     = [ 25/24     -49/48     125/16  -85/12  1/4 ]'";
-      //<< "b     = [ 59/48     -17/96     225/32  -85/12  0   ]'";
+      // << "b     = [ 59/48     -17/96     225/32  -85/12  0   ]'";
     return Description.str();
   }
 
diff --git a/packages/tempus/src/Tempus_StepperRKModifierXBase.hpp b/packages/tempus/src/Tempus_StepperRKModifierXBase.hpp
index 6e3e15aa23a7..961daf45bee6 100644
--- a/packages/tempus/src/Tempus_StepperRKModifierXBase.hpp
+++ b/packages/tempus/src/Tempus_StepperRKModifierXBase.hpp
@@ -75,6 +75,7 @@ class StepperRKModifierXBase
     RCP<SolutionState<Scalar> > workingState = sh->getWorkingState();
     const Scalar time = workingState->getTime();
     const Scalar dt   = workingState->getTimeStep();
+    const int stageNumber = stepper->getStageNumber();
     RCP<Thyra::VectorBase<Scalar> > x;
 
     switch(actLoc) {
@@ -105,13 +106,13 @@ class StepperRKModifierXBase
       case StepperRKAppAction<Scalar>::BEFORE_EXPLICIT_EVAL:
       {
         modType = X_BEFORE_EXPLICIT_EVAL;
-        x = workingState->getX();
+        x = stepper->getStageX();
         break;
       }
       case StepperRKAppAction<Scalar>::END_STAGE:
       {
-        modType = XDOT_END_STAGE;
-        x = stepper->getStepperXDot(workingState);
+        modType = X_END_STAGE;
+        x = stepper->getStageX();
         break;
       }
       case StepperRKAppAction<Scalar>::END_STEP:
@@ -125,7 +126,7 @@ class StepperRKModifierXBase
         "Error - unknown action location.\n");
     }
 
-    this->modify(x, time, dt, modType);
+    this->modify(x, time, dt, stageNumber, modType);
   }
 
 public:
@@ -137,7 +138,7 @@ class StepperRKModifierXBase
     X_BEFORE_SOLVE,         ///< Modify \f$x\f$ before the implicit solve.
     X_AFTER_SOLVE,          ///< Modify \f$x\f$ after the implicit solve.
     X_BEFORE_EXPLICIT_EVAL, ///< Modify \f$x\f$ before the explicit evaluation.
-    XDOT_END_STAGE,         ///< Modify \f$\dot{x}\f$ at the end of the stage.
+    X_END_STAGE,            ///< Modify \f$x\f$ at the end of the stage.
     X_END_STEP              ///< Modify \f$x\f$ at the end of the step.
   };
 
@@ -145,6 +146,7 @@ class StepperRKModifierXBase
   virtual void modify(
     Teuchos::RCP<Thyra::VectorBase<Scalar> > /* x */,
     const Scalar /* time */, const Scalar /* dt */,
+    const int /* stageNumber */,
     const MODIFIER_TYPE modType) = 0;
 
 };
diff --git a/packages/tempus/src/Tempus_StepperRKModifierXDefault.hpp b/packages/tempus/src/Tempus_StepperRKModifierXDefault.hpp
index a06fef3578a5..b40591b4daff 100644
--- a/packages/tempus/src/Tempus_StepperRKModifierXDefault.hpp
+++ b/packages/tempus/src/Tempus_StepperRKModifierXDefault.hpp
@@ -39,6 +39,7 @@ class StepperRKModifierXDefault
   virtual void modify(
     Teuchos::RCP<Thyra::VectorBase<Scalar> > /* x */,
     const Scalar /* time */, const Scalar /* dt */,
+    const int /* stageNumber */,
     const typename StepperRKModifierXBase<Scalar>::MODIFIER_TYPE modType)
   {
     switch(modType) {
@@ -47,7 +48,7 @@ class StepperRKModifierXDefault
       case StepperRKModifierXBase<Scalar>::X_BEFORE_SOLVE:
       case StepperRKModifierXBase<Scalar>::X_AFTER_SOLVE:
       case StepperRKModifierXBase<Scalar>::X_BEFORE_EXPLICIT_EVAL:
-      case StepperRKModifierXBase<Scalar>::XDOT_END_STAGE:
+      case StepperRKModifierXBase<Scalar>::X_END_STAGE:
       case StepperRKModifierXBase<Scalar>::X_END_STEP:
       {
         // No-op.
diff --git a/packages/tempus/src/Tempus_Stepper_decl.hpp b/packages/tempus/src/Tempus_Stepper_decl.hpp
index 303f56452094..7d943bbca245 100644
--- a/packages/tempus/src/Tempus_Stepper_decl.hpp
+++ b/packages/tempus/src/Tempus_Stepper_decl.hpp
@@ -185,10 +185,10 @@ class Stepper
 
 private:
 
-  std::string stepperType_;             //< Name of stepper type
-  bool useFSAL_ = false;                //< Use First-Step-As-Last (FSAL) principle
-  std::string ICConsistency_ = std::string("None");  //< Type of consistency to apply to ICs.
-  bool ICConsistencyCheck_ = true;      //< Check if the initial condition is consistent
+  std::string stepperType_;        ///< Name of stepper type
+  bool useFSAL_ = false;           ///< Use First-Step-As-Last (FSAL) principle
+  std::string ICConsistency_ = std::string("None");  ///< Type of consistency to apply to ICs.
+  bool ICConsistencyCheck_ = true; ///< Check if the initial condition is consistent
 
   // RCP to SolutionState memory or Stepper temporary memory (if needed).
   Teuchos::RCP<Thyra::VectorBase<Scalar> > stepperX_;
@@ -209,7 +209,7 @@ class Stepper
   virtual void setStepperXDotDot(Teuchos::RCP<Thyra::VectorBase<Scalar> > xDotDot)
   { stepperXDotDot_ = xDotDot; }
 
-  bool isInitialized_ = false; //< True if stepper's member data is initialized.
+  bool isInitialized_ = false; ///< True if stepper's member data is initialized.
 };
 
 
diff --git a/packages/tempus/src/Tempus_WrapperModelEvaluatorPairPartIMEX_Basic_decl.hpp b/packages/tempus/src/Tempus_WrapperModelEvaluatorPairPartIMEX_Basic_decl.hpp
index 1732dd416a43..e521c0020abd 100644
--- a/packages/tempus/src/Tempus_WrapperModelEvaluatorPairPartIMEX_Basic_decl.hpp
+++ b/packages/tempus/src/Tempus_WrapperModelEvaluatorPairPartIMEX_Basic_decl.hpp
@@ -184,8 +184,8 @@ class WrapperModelEvaluatorPairPartIMEX_Basic
   Thyra::ModelEvaluatorBase::OutArgs<Scalar>         wrapperImplicitOutArgs_;
 
   int numExplicitOnlyBlocks_;
-  int parameterIndex_;    //< implicit parameter index for explicit-only vector
-  bool useImplicitModel_; //< if true, use implicitModel_ else explicitModel_
+  int parameterIndex_;    ///< implicit parameter index for explicit-only vector
+  bool useImplicitModel_; ///< if true, use implicitModel_ else explicitModel_
 };
 
 } // namespace Tempus
diff --git a/packages/tempus/unit_test/Tempus_UnitTest_IMEX_RK.cpp b/packages/tempus/unit_test/Tempus_UnitTest_IMEX_RK.cpp
index 0b0fb70fa681..e419cb42ea66 100644
--- a/packages/tempus/unit_test/Tempus_UnitTest_IMEX_RK.cpp
+++ b/packages/tempus/unit_test/Tempus_UnitTest_IMEX_RK.cpp
@@ -92,6 +92,9 @@ TEUCHOS_UNIT_TEST(IMEX_RK, Default_Construction)
   stepper->setImplicitTableau(implicitTableau);        stepper->initialize();  TEUCHOS_TEST_FOR_EXCEPT(!stepper->isInitialized());
   stepper->setOrder(order);                            stepper->initialize();  TEUCHOS_TEST_FOR_EXCEPT(!stepper->isInitialized());
 
+  TEUCHOS_TEST_FOR_EXCEPT(explicitTableau != stepper->getTableau());
+  TEUCHOS_TEST_FOR_EXCEPT(explicitTableau != stepper->getExplicitTableau());
+  TEUCHOS_TEST_FOR_EXCEPT(implicitTableau != stepper->getImplicitTableau());
 
   // Full argument list construction.
 #ifndef TEMPUS_HIDE_DEPRECATED_CODE
diff --git a/packages/tempus/unit_test/Tempus_UnitTest_IMEX_RK_Partition.cpp b/packages/tempus/unit_test/Tempus_UnitTest_IMEX_RK_Partition.cpp
index cf7d173510bf..6b1961e28f65 100644
--- a/packages/tempus/unit_test/Tempus_UnitTest_IMEX_RK_Partition.cpp
+++ b/packages/tempus/unit_test/Tempus_UnitTest_IMEX_RK_Partition.cpp
@@ -99,6 +99,9 @@ TEUCHOS_UNIT_TEST(IMEX_RK_Partition, Default_Construction)
   stepper->setImplicitTableau(implicitTableau);        stepper->initialize();  TEUCHOS_TEST_FOR_EXCEPT(!stepper->isInitialized());
   stepper->setOrder(order);                            stepper->initialize();  TEUCHOS_TEST_FOR_EXCEPT(!stepper->isInitialized());
 
+  TEUCHOS_TEST_FOR_EXCEPT(explicitTableau != stepper->getTableau());
+  TEUCHOS_TEST_FOR_EXCEPT(explicitTableau != stepper->getExplicitTableau());
+  TEUCHOS_TEST_FOR_EXCEPT(implicitTableau != stepper->getImplicitTableau());
 
   // Full argument list construction.
 #ifndef TEMPUS_HIDE_DEPRECATED_CODE
diff --git a/packages/tempus/unit_test/Tempus_UnitTest_Utils.hpp b/packages/tempus/unit_test/Tempus_UnitTest_Utils.hpp
index 89e7d3afad96..7327a6145e6f 100644
--- a/packages/tempus/unit_test/Tempus_UnitTest_Utils.hpp
+++ b/packages/tempus/unit_test/Tempus_UnitTest_Utils.hpp
@@ -17,6 +17,7 @@
 #include "Tempus_StepperRKModifierDefault.hpp"
 #include "Tempus_StepperRKModifierXDefault.hpp"
 #include "Tempus_StepperRKObserverDefault.hpp"
+#include "Tempus_StepperRKAppActionComposite.hpp"
 
 #include "../TestModels/SinCosModel.hpp"
 #include "../TestModels/VanDerPolModel.hpp"
@@ -509,6 +510,8 @@ class StepperRKModifierTest
         testBEGIN_STEP = true;
         auto x = sh->getCurrentState()->getX();
         testCurrentValue = get_ele(*(x), 0);
+        testType = stepper->getStepperType() + " - Modifier";
+        stepper->setStepperType(testType);
         break;
       }
       case StepperRKAppAction<double>::BEGIN_STAGE:
@@ -520,18 +523,11 @@ class StepperRKModifierTest
       {
         testBEFORE_SOLVE = true;
         testDt = sh->getWorkingState()->getTimeStep()/10.0;
-        sh->getWorkingState()->setTimeStep(testDt);
         break;
       }
       case StepperRKAppAction<double>::AFTER_SOLVE:
       {
         testAFTER_SOLVE = true;
-        static bool done_once = false;
-        if (!done_once) {
-          testType = stepper->getStepperType() + " - Modifier";
-          done_once = true;
-        }
-        stepper->setStepperType(testType);
         break;
       }
       case StepperRKAppAction<double>::BEFORE_EXPLICIT_EVAL:
@@ -619,13 +615,12 @@ class StepperRKObserverTest
       {
         testBEFORE_SOLVE = true;
         testDt = sh->getWorkingState()->getTimeStep()/10.0;
-        sh->getWorkingState()->setTimeStep(testDt);
         break;
       }
       case StepperRKAppAction<double>::AFTER_SOLVE:
       {
         testAFTER_SOLVE = true;
-        testType = stepper->getStepperType();
+        testType = stepper->getStepperType() + " - Observer";
         break;
       }
       case StepperRKAppAction<double>::BEFORE_EXPLICIT_EVAL:
@@ -680,9 +675,11 @@ class StepperRKModifierXTest
       testXDOT_END_STAGE(false),
       testX_END_STEP(false),
       testX(-0.99),
-      testXDot(-0.99),
+      testEndStageX(-0.99),
       testDt(-1.5),
-      testTime(-1.5)
+      testTime(-1.5),
+      testStageNumber(-1),
+      testStageX(-0.99)
   {}
 
   /// Destructor
@@ -692,6 +689,7 @@ class StepperRKModifierXTest
   virtual void modify(
     Teuchos::RCP<Thyra::VectorBase<double> > x,
     const double time, const double dt,
+    const int stageNumber,
     const typename Tempus::StepperRKModifierXBase<double>::MODIFIER_TYPE modType)
   {
     switch(modType) {
@@ -721,12 +719,14 @@ class StepperRKModifierXTest
       case StepperRKModifierXBase<double>::X_BEFORE_EXPLICIT_EVAL:
       {
         testX_BEFORE_EXPLICIT_EVAL = true;
+        testStageNumber = stageNumber;
+        testStageX = get_ele(*(x), 0);  // x should be the stage value.
         break;
       }
-      case StepperRKModifierXBase<double>::XDOT_END_STAGE:
+      case StepperRKModifierXBase<double>::X_END_STAGE:
       {
         testXDOT_END_STAGE = true;
-        testXDot = get_ele(*(x), 0);
+        testEndStageX = get_ele(*(x), 0);
         break;
       }
       case StepperRKModifierXBase<double>::X_END_STEP:
@@ -748,9 +748,11 @@ class StepperRKModifierXTest
   bool testXDOT_END_STAGE;
   bool testX_END_STEP;
   double testX;
-  double testXDot;
+  double testEndStageX;
   double testDt;
   double testTime;
+  int testStageNumber;
+  double testStageX;
 };
 
 
@@ -797,7 +799,7 @@ void testRKAppAction(
     x = solutionHistory->getWorkingState()->getX();
     TEST_FLOATING_EQUALITY(modifier->testWorkingValue,get_ele(*(x), 0),1.0e-15);
     auto Dt = solutionHistory->getWorkingState()->getTimeStep();
-    TEST_FLOATING_EQUALITY(modifier->testDt, Dt, 1.0e-15);
+    TEST_FLOATING_EQUALITY(modifier->testDt, Dt/10.0, 1.0e-15);
 
     TEST_COMPARE(modifier->testType, ==, testType);
   }
@@ -810,7 +812,6 @@ void testRKAppAction(
     stepper->setStepperType(testTypeOrig);
     stepper->initialize();
     TEUCHOS_TEST_FOR_EXCEPT(!stepper->isInitialized());
-    auto testType = testTypeOrig;
 
     // Create a SolutionHistory.
     auto solutionHistory = Tempus::createSolutionHistoryME(model);
@@ -837,8 +838,9 @@ void testRKAppAction(
     x = solutionHistory->getWorkingState()->getX();
     TEST_FLOATING_EQUALITY(observer->testWorkingValue,get_ele(*(x), 0),1.0e-15);
     auto Dt = solutionHistory->getWorkingState()->getTimeStep();
-    TEST_FLOATING_EQUALITY(observer->testDt, Dt, 1.0e-15);
+    TEST_FLOATING_EQUALITY(observer->testDt, Dt/10.0, 1.0e-15);
 
+    auto testType = testTypeOrig + " - Observer";
     TEST_COMPARE(observer->testType, ==, testType);
   }
 
@@ -873,14 +875,225 @@ void testRKAppAction(
     // Testing that values can be set through the modifierX.
     auto x = solutionHistory->getCurrentState()->getX();
     TEST_FLOATING_EQUALITY(modifierX->testX, get_ele(*(x), 0), 1.0e-15);
-    // Temporary memory for xDot is not guarranteed to exist outside the Stepper
-    auto xDot = stepper->getStepperXDot(solutionHistory->getWorkingState());
-    TEST_FLOATING_EQUALITY(modifierX->testXDot, get_ele(*(xDot), 0),1.0e-15);
     auto Dt = solutionHistory->getWorkingState()->getTimeStep();
     TEST_FLOATING_EQUALITY(modifierX->testDt, Dt, 1.0e-15);
 
     auto time = solutionHistory->getWorkingState()->getTime();
     TEST_FLOATING_EQUALITY(modifierX->testTime, time, 1.0e-15);
+
+    // Stage Number should be -1 outside stage loop.
+    TEST_COMPARE(stepper->getStageNumber(), ==, -1);
+    // The last stage number through X_BEFORE_EXPLICIT_EVAL should be
+    // the number of stages minus one.
+    TEST_COMPARE(modifierX->testStageNumber,==,stepper->getNumberOfStages()-1);
+
+    if (rcp_dynamic_cast<Tempus::StepperIMEX_RK<double>>(stepper) != Teuchos::null ||
+        rcp_dynamic_cast<Tempus::StepperIMEX_RK_Partition<double>>(stepper) != Teuchos::null) {
+      TEST_FLOATING_EQUALITY(modifierX->testStageX, 2.0, 1.0e-15);
+      TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 2.0,1.0e-15);
+    } else if (stepper->isImplicit()) {
+      // For implicit steppers, stageX is separate memory which can be tested.
+      auto stageX = stepper->getStageX();
+      TEST_FLOATING_EQUALITY(modifierX->testStageX, get_ele(*(stageX), 0),1.0e-15);
+      TEST_FLOATING_EQUALITY(modifierX->testEndStageX, get_ele(*(stageX), 0),1.0e-15);
+    } else {
+      // For explicit steppers, stageX is under written and not available
+      // outside takeStep, so direct comparisons are needed.
+      if (rcp_dynamic_cast<Tempus::StepperERK_3_8Rule<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09966666666666668, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09966666666666668, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_3Stage3rdOrder<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.1, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.1, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_3Stage3rdOrderHeun<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.06666666666666667, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.06666666666666667, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_3Stage3rdOrderTVD<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.05, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.05, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_4Stage3rdOrderRunge<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09950000000000001, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09950000000000001, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_4Stage4thOrder<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09975000000000001, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09975000000000001, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_5Stage3rdOrderKandG<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.06662222222222222, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.06662222222222222, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_BogackiShampine32<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09983333333333333, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09983333333333333, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_ForwardEuler<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.0, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.0, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_General<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09975000000000001, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09975000000000001, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_Merson45<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09983333333333332, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09983333333333332, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_Midpoint<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.05, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.05, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_Trapezoidal<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.1, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.1, 1.0e-15);
+      } else {
+        TEUCHOS_TEST_FOR_EXCEPTION(true, std::logic_error,
+          "Error - unknown stepperType = "+stepper->getStepperType());
+      }
+    }
+  }
+
+
+  // Test Composite.
+  {
+    stepper->setModel(model);
+
+    auto modifier = rcp(new StepperRKModifierTest());
+    auto observer = rcp(new StepperRKObserverTest());
+    auto modifierX = rcp(new StepperRKModifierXTest());
+    auto composite = rcp(new Tempus::StepperRKAppActionComposite<double>());
+
+    composite->addRKAppAction(modifier);
+    composite->addRKAppAction(observer);
+    composite->addRKAppAction(modifierX);
+    stepper->setAppAction(composite);
+
+    stepper->initialize();
+    TEUCHOS_TEST_FOR_EXCEPT(!stepper->isInitialized());
+
+    // Create a SolutionHistory.
+    auto solutionHistory = Tempus::createSolutionHistoryME(model);
+
+    // Take one time step.
+    stepper->setInitialConditions(solutionHistory);
+    solutionHistory->initWorkingState();
+    double dt = 0.1;
+    solutionHistory->getWorkingState()->setTimeStep(dt);
+    stepper->takeStep(solutionHistory);
+
+    auto xCS = solutionHistory->getCurrentState()->getX();
+    auto xWS = solutionHistory->getWorkingState()->getX();
+    auto Dt = solutionHistory->getWorkingState()->getTimeStep();
+
+    // Test Modifier.
+    // Testing that each ACTION_LOCATION has been called.
+    TEST_COMPARE(modifier->testBEGIN_STEP, ==, true);
+    TEST_COMPARE(modifier->testBEGIN_STAGE, ==, true);
+    TEST_COMPARE(modifier->testBEFORE_SOLVE, ==, true);
+    TEST_COMPARE(modifier->testAFTER_SOLVE, ==, true);
+    TEST_COMPARE(modifier->testBEFORE_EXPLICIT_EVAL, ==, true);
+    TEST_COMPARE(modifier->testEND_STAGE, ==, true);
+    TEST_COMPARE(modifier->testEND_STEP, ==, true);
+
+    // Testing that values can be set through the modifier.
+    TEST_FLOATING_EQUALITY(modifier->testCurrentValue, get_ele(*(xCS), 0),1.0e-15);
+    TEST_FLOATING_EQUALITY(modifier->testWorkingValue, get_ele(*(xWS), 0),1.0e-15);
+    TEST_FLOATING_EQUALITY(modifier->testDt, Dt/10.0, 1.0e-15);
+
+    auto testType = testTypeOrig + " - Modifier";
+    TEST_COMPARE(modifier->testType, ==, testType);
+
+
+    // Test Observer.
+    // Testing that each ACTION_LOCATION has been called.
+    TEST_COMPARE(observer->testBEGIN_STEP, ==, true);
+    TEST_COMPARE(observer->testBEGIN_STAGE, ==, true);
+    TEST_COMPARE(observer->testBEFORE_SOLVE, ==, true);
+    TEST_COMPARE(observer->testAFTER_SOLVE, ==, true);
+    TEST_COMPARE(observer->testBEFORE_EXPLICIT_EVAL, ==, true);
+    TEST_COMPARE(observer->testEND_STAGE, ==, true);
+    TEST_COMPARE(observer->testEND_STEP, ==, true);
+
+    // Testing that values can be observed through the observer.
+    TEST_FLOATING_EQUALITY(observer->testCurrentValue, get_ele(*(xCS), 0),1.0e-15);
+    TEST_FLOATING_EQUALITY(observer->testWorkingValue, get_ele(*(xWS), 0),1.0e-15);
+    TEST_FLOATING_EQUALITY(observer->testDt, Dt/10.0, 1.0e-15);
+
+    testType = testType + " - Observer";
+    TEST_COMPARE(observer->testType, ==, testType);
+
+
+    // Test ModifierX.
+    // Testing that each ACTION_LOCATION has been called.
+    TEST_COMPARE(modifierX->testX_BEGIN_STEP, ==, true);
+    TEST_COMPARE(modifierX->testX_BEGIN_STAGE, ==, true);
+    TEST_COMPARE(modifierX->testX_BEFORE_SOLVE, ==, true);
+    TEST_COMPARE(modifierX->testX_AFTER_SOLVE, ==, true);
+    TEST_COMPARE(modifierX->testX_BEFORE_EXPLICIT_EVAL, ==, true);
+    TEST_COMPARE(modifierX->testXDOT_END_STAGE, ==, true);
+    TEST_COMPARE(modifierX->testX_END_STEP, ==, true);
+
+    // Testing that values can be set through the modifierX.
+    TEST_FLOATING_EQUALITY(modifierX->testX, get_ele(*(xCS), 0), 1.0e-15);
+    TEST_FLOATING_EQUALITY(modifierX->testDt, Dt, 1.0e-15);
+
+    auto time = solutionHistory->getWorkingState()->getTime();
+    TEST_FLOATING_EQUALITY(modifierX->testTime, time, 1.0e-15);
+
+    // Stage Number should be -1 outside stage loop.
+    TEST_COMPARE(stepper->getStageNumber(), ==, -1);
+    // The last stage number through X_BEFORE_EXPLICIT_EVAL should be
+    // the number of stages minus one.
+    TEST_COMPARE(modifierX->testStageNumber,==,stepper->getNumberOfStages()-1);
+
+    if (rcp_dynamic_cast<Tempus::StepperIMEX_RK<double>>(stepper) != Teuchos::null ||
+        rcp_dynamic_cast<Tempus::StepperIMEX_RK_Partition<double>>(stepper) != Teuchos::null) {
+      TEST_FLOATING_EQUALITY(modifierX->testStageX, 2.0, 1.0e-15);
+      TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 2.0,1.0e-15);
+    } else if (stepper->isImplicit()) {
+      // For implicit steppers, stageX is separate memory which can be tested.
+      auto stageX = stepper->getStageX();
+      TEST_FLOATING_EQUALITY(modifierX->testStageX, get_ele(*(stageX), 0),1.0e-15);
+      TEST_FLOATING_EQUALITY(modifierX->testEndStageX, get_ele(*(stageX), 0),1.0e-15);
+    } else {
+      // For explicit steppers, stageX is under written and not available
+      // outside takeStep, so direct comparisons are needed.
+      if (rcp_dynamic_cast<Tempus::StepperERK_3_8Rule<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09966666666666668, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09966666666666668, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_3Stage3rdOrder<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.1, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.1, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_3Stage3rdOrderHeun<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.06666666666666667, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.06666666666666667, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_3Stage3rdOrderTVD<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.05, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.05, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_4Stage3rdOrderRunge<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09950000000000001, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09950000000000001, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_4Stage4thOrder<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09975000000000001, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09975000000000001, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_5Stage3rdOrderKandG<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.06662222222222222, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.06662222222222222, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_BogackiShampine32<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09983333333333333, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09983333333333333, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_ForwardEuler<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.0, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.0, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_General<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09975000000000001, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09975000000000001, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_Merson45<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.09983333333333332, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.09983333333333332, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_Midpoint<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.05, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.05, 1.0e-15);
+      } else if (rcp_dynamic_cast<Tempus::StepperERK_Trapezoidal<double>>(stepper) != Teuchos::null) {
+        TEST_FLOATING_EQUALITY(modifierX->testStageX, 0.1, 1.0e-15);
+        TEST_FLOATING_EQUALITY(modifierX->testEndStageX, 0.1, 1.0e-15);
+      } else {
+        TEUCHOS_TEST_FOR_EXCEPTION(true, std::logic_error,
+          "Error - unknown stepperType = "+stepper->getStepperType());
+      }
+    }
   }
 }