diff --git a/Mu2eKinKal/inc/KKFit.hh b/Mu2eKinKal/inc/KKFit.hh
index 82a40a11b5..5b5077d35b 100644
--- a/Mu2eKinKal/inc/KKFit.hh
+++ b/Mu2eKinKal/inc/KKFit.hh
@@ -159,7 +159,6 @@ namespace mu2e {
       double addStrawMinDz_;
       int strawNBuffer_;
       bool saveHitCalib_;
-      KinKalGeom smap_;
       SurfaceIdCollection ssids_;
   };
 
@@ -207,7 +206,7 @@ namespace mu2e {
     } else {
       throw cet::exception("RECO")<<"mu2e::KKFit: unknown trajectory option "<< fitconfig.saveTraj() << endl;
     }
-    // Lookup surfaces to sample; this interface is deprecatecd and should be replaced with extrapolation TODO
+    // surfaces to sample; this interface is deprecatecd and should be replaced with extrapolation TODO
     for(auto const& sidname : fitconfig.sampleSurfaces()){
       ssids_.push_back(SurfaceId(sidname,-1)); // match all elements
     }
@@ -866,8 +865,10 @@ namespace mu2e {
   template <class KTRAJ> void KKFit<KTRAJ>::sampleFit(KKTRK& kktrk) const {
     // translate the sample and extend surface names to actual surfaces using the KinKalGeom.  This should come from the
     // extrapolation and sampling options
+    GeomHandle<mu2e::KinKalGeom> kkg_h;
+    auto const& kkg = *kkg_h;
     KinKalGeom::SurfacePairCollection tosample; // surfaces to sample the fit
-    smap_.surfaces(ssids_,tosample);
+    kkg.surfaces(ssids_,tosample);
 
     auto const& ptraj = kktrk.fitTraj();
     std::vector<TimeRange> ranges;
diff --git a/Mu2eKinKal/src/CentralHelixFit_module.cc b/Mu2eKinKal/src/CentralHelixFit_module.cc
index c319450e71..d45316dd45 100644
--- a/Mu2eKinKal/src/CentralHelixFit_module.cc
+++ b/Mu2eKinKal/src/CentralHelixFit_module.cc
@@ -121,7 +121,7 @@ namespace mu2e {
     fhicl::Atom<float> sampleTBuff { Name("SampleTimeBuffer"), Comment("Time buffer for sample intersections (nsec)") };
     fhicl::Atom<bool> useFitCharge { Name("UseFitCharge"), Comment("Set the PDG particle according to the fit charge; otherwise reject fits that don't agree with the PDG particle charge") };
     fhicl::Atom<float> minCenterRho { Name("MinCenterRho"), Comment("Minimum transverse distance from the helix axis to the Z axis to consider the fit non-degenerate (mm)") };
-};
+  };
 
   struct GlobalConfig {
     fhicl::Table<KKCHModuleConfig> modSettings { Name("ModuleSettings") };
@@ -129,7 +129,7 @@ namespace mu2e {
     fhicl::Table<KKConfig> fitSettings { Name("FitSettings") };
     fhicl::Table<KKConfig> extSettings { Name("ExtensionSettings") };
     fhicl::Table<KKMaterialConfig> matSettings { Name("MaterialSettings") };
-// helix module specific config
+    // helix module specific config
   };
 
   class CentralHelixFit : public art::EDProducer {
@@ -170,9 +170,10 @@ namespace mu2e {
       bool useFitCharge_; // Set the PDG particle to agree with the fit charge
       double minCenterRho_; // min center distance to z axis
       bool sampleinrange_, sampleinbounds_; // require samples to be in range or on surface
-      KinKalGeom::SurfacePairCollection sample_; // surfaces to sample the fit
+      SurfaceIdCollection ssids_;
+      KinKalGeom::SurfacePairCollection surfacess_to_sample_; // surfaces to sample the fit
       std::array<double,KinKal::NParams()> paramconstraints_;
-    };
+  };
 
   CentralHelixFit::CentralHelixFit(const Parameters& settings) : art::EDProducer{settings},
     fitflag_(TrkFitFlag::KKCentralHelix),
@@ -218,14 +219,10 @@ namespace mu2e {
         fixedfield_ = true;
         kkbf_ = std::move(std::make_unique<KKConstantBField>(VEC3(0.0,0.0,bz)));
       }
-      SurfaceIdCollection ssids;
+      // surfaces to sample; this interface is deprecatecd and should be replaced with extrapolation TODO
       for(auto const& sidname : settings().modSettings().sampleSurfaces()) {
-        ssids.push_back(SurfaceId(sidname,-1)); // match all elements
+        ssids_.push_back(SurfaceId(sidname,-1)); // match all elements
       }
-      // translate the sample and extend surface names to actual surfaces using the KinKalGeom.  This should come from the
-      // geometry service eventually, TODO
-      KinKalGeom smap;
-      smap.surfaces(ssids,sample_);
     }
 
   void CentralHelixFit::beginRun(art::Run& run) {
@@ -240,6 +237,10 @@ namespace mu2e {
       kkbf_ = std::move(std::make_unique<KKBField>(*bfmgr,*det));
     }
     if(print_ > 0) kkbf_->print(std::cout);
+    // translate the sample surface names to actual surfaces using the KinKalGeom. This must be done after construction as the KKGeom object now comes from GeometryService
+    GeomHandle<mu2e::KinKalGeom> kkg_h;
+    auto const& kkg = *kkg_h;
+    kkg.surfaces(ssids_,surfacess_to_sample_);
   }
 
   void CentralHelixFit::produce(art::Event& event ) {
@@ -399,7 +400,7 @@ namespace mu2e {
   void CentralHelixFit::sampleFit(KKTRK& kktrk) const {
     auto const& ftraj = kktrk.fitTraj();
     double tbeg = ftraj.range().begin();
-    for(auto const& surf : sample_){
+    for(auto const& surf : surfacess_to_sample_){
       // search for intersections with each surface from the begining
       double tstart = tbeg - sampletbuff_;
       bool goodinter(true);
diff --git a/Mu2eKinKal/src/KinematicLineFit_module.cc b/Mu2eKinKal/src/KinematicLineFit_module.cc
index 5dd1ad5000..77cb6b665f 100644
--- a/Mu2eKinKal/src/KinematicLineFit_module.cc
+++ b/Mu2eKinKal/src/KinematicLineFit_module.cc
@@ -51,6 +51,7 @@
 #include "Offline/Mu2eKinKal/inc/KKStrawHit.hh"
 #include "Offline/Mu2eKinKal/inc/KKBField.hh"
 #include "Offline/Mu2eKinKal/inc/KKFitUtilities.hh"
+#include "Offline/Mu2eKinKal/inc/KKShellXing.hh"
 #include "Offline/Mu2eKinKal/inc/ExtrapolateTCRV.hh"
 // root
 #include "TH1F.h"
@@ -171,10 +172,12 @@ namespace mu2e {
     double intertol_; // surface intersection tolerance (mm)
     double sampletbuff_; // simple time buffer; replace this with extrapolation TODO
     bool sampleinrange_, sampleinbounds_; // require samples to be in range or on surface
-    KinKalGeom::SurfacePairCollection sample_; // surfaces to sample the fit
     bool extrapolate_, toCRV_;
-    ExtrapolateTCRV TCRV_; // extrapolation predicate based on Z values
-    double tcrvthick_ = 0.1056; // st foil thickness: should come from geometry service TODO
+    double maxdt_ = 0.0, btol_ = 0.0, minv_ = 0.0;
+    SurfaceIdCollection ssids_;
+    KinKalGeom::SurfacePairCollection surfacess_to_sample_; // surfaces to sample the fit
+    int extrapdebug_ = 0;
+    double tcrvthick_ = 150.0; // CRV sector thickness: should come from geometry service TODO
     Config config_; // initial fit configuration object
     Config exconfig_; // extension configuration object
   };
@@ -221,28 +224,21 @@ namespace mu2e {
       }else{
         throw cet::exception("RECO")<<"mu2e::KinematicLineFit: Parameter constraint configuration error"<< endl;
       }
-      SurfaceIdCollection ssids;
       for(auto const& sidname : settings().modSettings().sampleSurfaces()) {
-        ssids.push_back(SurfaceId(sidname,-1)); // match all elements
+        ssids_.push_back(SurfaceId(sidname,-1)); // match all elements
       }
-      // translate the sample and extend surface names to actual surfaces using the KinKalGeom.  This should come from the
-      // geometry service eventually, TODO
-      GeomHandle<mu2e::KinKalGeom> kkg_h;
-      auto const& kkg = *kkg_h;
-      kkg.surfaces(ssids,sample_);
       // configure extrapolation
       if(settings().Extrapolation()){
         extrapolate_ = true;
         toCRV_ = settings().Extrapolation()->ToCRV();
         // global configs
-        double maxdt = settings().Extrapolation()->MaxDt();
-        double btol =  settings().extSettings().btol(); // use the same BField cor. tolerance as in fit extension
-        double minv = settings().Extrapolation()->MinV();
-        int debug =  settings().Extrapolation()->Debug();
-        // extrapolate to the front of the tracker
-        TCRV_ = ExtrapolateTCRV(maxdt,btol,intertol_,minv,*kkg.TCRV(),debug);
+        maxdt_ = settings().Extrapolation()->MaxDt();
+        btol_ =  settings().extSettings().btol(); // use the same BField cor. tolerance as in fit extension
+        minv_ = settings().Extrapolation()->MinV();
+        extrapdebug_ =  settings().Extrapolation()->Debug();
       }
 
+
       if(print_ > 0) std::cout << config_;
 
 
@@ -259,6 +255,10 @@ namespace mu2e {
     GeomHandle<BFieldManager> bfmgr;
     GeomHandle<DetectorSystem> det;
     kkbf_ = std::make_unique<KKBField>(*bfmgr,*det);
+    // translate the sample surface names to actual surfaces using the KinKalGeom. This must be done after construction as the KKGeom object now comes from GeometryService
+    GeomHandle<mu2e::KinKalGeom> kkg_h;
+    auto const& kkg = *kkg_h;
+    kkg.surfaces(ssids_,surfacess_to_sample_);
   }
 
   void KinematicLineFit::produce(art::Event& event ) {
@@ -385,7 +385,7 @@ namespace mu2e {
     kktrk.extendTraj(extrange);
     double tbeg = ftraj.range().begin();
 
-    for(auto const& surf : sample_){
+    for(auto const& surf : surfacess_to_sample_){
       // search for intersections with each surface from the begining
       double tstart = tbeg;
       bool goodinter(true);
@@ -411,6 +411,11 @@ namespace mu2e {
   }
 
   void KinematicLineFit::extrapolate(KKTRK& ktrk) const {
+    GeomHandle<mu2e::KinKalGeom> kkg_h;
+    auto const& kkg = *kkg_h;
+    // extrapolate to the extracted CRV. This function should be migrated to KKExtrap TODO
+    auto TCRV = ExtrapolateTCRV(maxdt_,btol_,intertol_,minv_,*kkg.TCRV(),extrapdebug_);
+
     auto const& ftraj = ktrk.fitTraj();
     static const SurfaceId TCRVSID("TCRV");
     auto dir0 = ftraj.direction(ftraj.t0());
@@ -421,18 +426,18 @@ namespace mu2e {
       // iterate until the extrapolation condition is met
       double time = starttime;
       double tstart = time;
-      while(fabs(time-tstart) < TCRV_.maxDt() && TCRV_.needsExtrapolation(ftraj,tdir) ){
-        TimeRange range = tdir == TimeDir::forwards ? TimeRange(time,time+TCRV_.step()) : TimeRange(time-TCRV_.step(),time);
+      while(fabs(time-tstart) < TCRV.maxDt() && TCRV.needsExtrapolation(ftraj,tdir) ){
+        TimeRange range = tdir == TimeDir::forwards ? TimeRange(time,time+TCRV.step()) : TimeRange(time-TCRV.step(),time);
         ktrk.extendTraj(range);
         time = tdir == TimeDir::forwards ? range.end() : range.begin();
       }
       hadintersection = false;
-      if (TCRV_.intersection().good()){
+      if (TCRV.intersection().good()){
         hadintersection = true;
         // we have a good intersection. Use this to create a Shell material Xing
         auto const& reftrajptr = tdir == TimeDir::backwards ? ftraj.frontPtr() : ftraj.backPtr();
-        // FIXME material?
-        KKCRVXINGPTR crvxingptr = std::make_shared<KKCRVXING>(TCRV_.module(), TCRVSID, *kkmat_.STMaterial(),TCRV_.intersection(),reftrajptr,tcrvthick_,TCRV_.interTolerance());
+        // TODO add DS and shielding material
+        KKCRVXINGPTR crvxingptr = std::make_shared<KKCRVXING>(TCRV.module(), TCRVSID, *kkmat_.STMaterial(),TCRV.intersection(),reftrajptr,tcrvthick_,TCRV.interTolerance());
         ktrk.addTCRVXing(crvxingptr,tdir);
       }
     } while(hadintersection);