diff --git a/src/THcShower.cxx b/src/THcShower.cxx
index 00228e110a3eba13932ee27e0ea917c8febf30a1..9cfe34521fd448a1ba702166213041da301a3303 100644
--- a/src/THcShower.cxx
+++ b/src/THcShower.cxx
@@ -263,16 +263,16 @@ Int_t THcShower::ReadDatabase( const TDatime& date )
 
   BlockThick = new Double_t [fNLayers];
   fNBlocks = new UInt_t [fNLayers];
-  fNLayerZPos = new Double_t [fNLayers];
-  YPos = new Double_t [2*fNLayers];
+  fLayerZPos = new Double_t [fNLayers];
+  fYPos = new Double_t [2*fNLayers];
 
   for(UInt_t i=0;i<fNLayers;i++) {
     DBRequest list[]={
       {Form("cal_%s_thick",fLayerNames[i]), &BlockThick[i], kDouble},
       {Form("cal_%s_nr",fLayerNames[i]), &fNBlocks[i], kInt},
-      {Form("cal_%s_zpos",fLayerNames[i]), &fNLayerZPos[i], kDouble},
-      {Form("cal_%s_right",fLayerNames[i]), &YPos[2*i], kDouble},
-      {Form("cal_%s_left",fLayerNames[i]), &YPos[2*i+1], kDouble},
+      {Form("cal_%s_zpos",fLayerNames[i]), &fLayerZPos[i], kDouble},
+      {Form("cal_%s_right",fLayerNames[i]), &fYPos[2*i], kDouble},
+      {Form("cal_%s_left",fLayerNames[i]), &fYPos[2*i+1], kDouble},
       {0}
     };
     gHcParms->LoadParmValues((DBRequest*)&list, prefix);
@@ -280,11 +280,11 @@ Int_t THcShower::ReadDatabase( const TDatime& date )
 
   //Caution! Z positions (fronts) are off in hcal.param! Correct later on.
 
-  XPos = new Double_t* [fNLayers];
+  fXPos = new Double_t* [fNLayers];
   for(UInt_t i=0;i<fNLayers;i++) {
-    XPos[i] = new Double_t [fNBlocks[i]];
+    fXPos[i] = new Double_t [fNBlocks[i]];
     DBRequest list[]={
-      {Form("cal_%s_top",fLayerNames[i]),XPos[i], kDouble, fNBlocks[i]},
+      {Form("cal_%s_top",fLayerNames[i]),fXPos[i], kDouble, fNBlocks[i]},
       {0}
     };
     gHcParms->LoadParmValues((DBRequest*)&list, prefix);
@@ -296,12 +296,12 @@ Int_t THcShower::ReadDatabase( const TDatime& date )
       cout << "  Plane " << fLayerNames[i] << ":" << endl;
       cout << "    Block thickness: " << BlockThick[i] << endl;
       cout << "    NBlocks        : " << fNBlocks[i] << endl;
-      cout << "    Z Position     : " << fNLayerZPos[i] << endl;
-      cout << "    Y Positions    : " << YPos[2*i] << ", " << YPos[2*i+1]
+      cout << "    Z Position     : " << fLayerZPos[i] << endl;
+      cout << "    Y Positions    : " << fYPos[2*i] << ", " << fYPos[2*i+1]
 	   <<endl;
       cout << "    X Positions    :";
       for(UInt_t j=0; j<fNBlocks[i]; j++) {
-	cout << " " << XPos[i][j];
+	cout << " " << fXPos[i][j];
       }
       cout << endl;
     }
@@ -310,10 +310,10 @@ Int_t THcShower::ReadDatabase( const TDatime& date )
   // Fiducial volume limits, based on Plane 1 positions.
   //
 
-  fvXmin = XPos[0][0] + fvDelta;
-  fvXmax = XPos[0][fNBlocks[0]-1] + BlockThick[0] - fvDelta;
-  fvYmin = YPos[0] + fvDelta;
-  fvYmax = YPos[1] - fvDelta;
+  fvXmin = fXPos[0][0] + fvDelta;
+  fvXmax = fXPos[0][fNBlocks[0]-1] + BlockThick[0] - fvDelta;
+  fvYmin = fYPos[0] + fvDelta;
+  fvYmax = fYPos[1] - fvDelta;
 
   // Debug output.
   if (fdbg_init_cal) {
@@ -461,9 +461,9 @@ Int_t THcShower::ReadDatabase( const TDatime& date )
   // Origin of the calorimeter, at the centre of the face of the detector,
   // or at the centre of the front of the 1-st layer.
   //
-  Double_t xOrig = (XPos[0][0] + XPos[0][fNBlocks[0]-1])/2 + BlockThick[0]/2;
-  Double_t yOrig = (YPos[0] + YPos[1])/2;
-  Double_t zOrig = fNLayerZPos[0];
+  Double_t xOrig = (fXPos[0][0] + fXPos[0][fNBlocks[0]-1])/2 + BlockThick[0]/2;
+  Double_t yOrig = (fYPos[0] + fYPos[1])/2;
+  Double_t zOrig = fLayerZPos[0];
 
   fOrigin.SetXYZ(xOrig, yOrig, zOrig);
 
@@ -530,9 +530,9 @@ void THcShower::DeleteArrays()
 
   delete [] BlockThick;  BlockThick = NULL;
   delete [] fNBlocks;  fNBlocks = NULL;
-  delete [] fNLayerZPos;  fNLayerZPos = NULL;
-  delete [] XPos;  XPos = NULL;
-  delete [] ZPos;  ZPos = NULL;
+  delete [] fLayerZPos;  fLayerZPos = NULL;
+  delete [] fXPos;  fXPos = NULL;
+  delete [] fZPos;  fZPos = NULL;
 }
 
 //_____________________________________________________________________________
@@ -640,8 +640,8 @@ Int_t THcShower::CoarseProcess( TClonesArray& tracks)
       //
       //      Double_t Edep = fPlanes[j]->GetEmean(i);
       //      if (Edep > 0.) {                                 //hit
-      //	Double_t x = YPos[j][i] + BlockThick[j]/2.;    //top + thick/2
-      //	Double_t z = fNLayerZPos[j] + BlockThick[j]/2.;//front + thick/2
+      //	Double_t x = fYPos[j][i] + BlockThick[j]/2.;    //top + thick/2
+      //	Double_t z = fLayerZPos[j] + BlockThick[j]/2.;//front + thick/2
       //      	THcShowerHit* hit = new THcShowerHit(i,j,x,z,Edep);
 
       //ENGINE way.
@@ -654,8 +654,8 @@ Int_t THcShower::CoarseProcess( TClonesArray& tracks)
 	Double_t Edep = fPlanes[j]->GetEmean(i);
 	Double_t Epos = fPlanes[j]->GetEpos(i);
 	Double_t Eneg = fPlanes[j]->GetEneg(i);
-	Double_t x = XPos[j][i] + BlockThick[j]/2.;        //top + thick/2
-	Double_t z = fNLayerZPos[j] + BlockThick[j]/2.;    //front + thick/2
+	Double_t x = fXPos[j][i] + BlockThick[j]/2.;        //top + thick/2
+	Double_t z = fLayerZPos[j] + BlockThick[j]/2.;      //front + thick/2
 
 	THcShowerHit* hit = new THcShowerHit(i,j,x,z,Edep,Epos,Eneg);
 
diff --git a/src/THcShower.h b/src/THcShower.h
index d6005376e254e09d775c8602100ae7b0c92d4e39..a90b3ddcfc62c73bac6b15d9739c4a3be6d0f00c 100644
--- a/src/THcShower.h
+++ b/src/THcShower.h
@@ -155,7 +155,7 @@ public:
   Int_t GetNBlocks(Int_t NLayer) const { return fNBlocks[NLayer];}
 
   Double_t GetXPos(Int_t NLayer, Int_t NRaw) const {
-    return XPos[NLayer][NRaw];
+    return fXPos[NLayer][NRaw];
   }
 
   Double_t GetYPos(Int_t NLayer, Int_t Side) const {
@@ -163,10 +163,10 @@ public:
     //Side = 0 for postive (right) side
     //Side = 1 for negative (left) side
 
-    return YPos[2*NLayer+(1-Side)];
+    return fYPos[2*NLayer+(1-Side)];
   }
 
-  Double_t GetZPos(Int_t NLayer) const {return fNLayerZPos[NLayer];}
+  Double_t GetZPos(Int_t NLayer) const {return fLayerZPos[NLayer];}
 
   Double_t GetBlockThick(Int_t NLayer) {return BlockThick[NLayer];}
 
@@ -259,14 +259,14 @@ protected:
   UInt_t fNLayers;	        // Number of layers in the calorimeter
   UInt_t fNTotLayers;	        // Number of layers including array
   UInt_t fHasArray;		// If !=0 fly's eye array behind preshower
-  Double_t* fNLayerZPos;	// Z positions of fronts of layers
+  Double_t* fLayerZPos;	        // Z positions of fronts of layers
   // Following apply to just sideways readout layers
   Double_t* BlockThick;		// Thickness of blocks
   UInt_t* fNBlocks;              // [fNLayers] number of blocks per layer
   UInt_t fNTotBlocks;            // Total number of shower counter blocks
-  Double_t** XPos;		// [fNLayers] X,Y,Z positions of blocks
-  Double_t* YPos;
-  Double_t* ZPos;
+  Double_t** fXPos;		// [fNLayers] X,Y,Z positions of blocks
+  Double_t* fYPos;
+  Double_t* fZPos;
   UInt_t fNegCols;               // # of columns with neg. side PMTs only.
   Double_t fSlop;               // Track to cluster vertical slop distance.
   Int_t fvTest;                 // fiducial volume test flag for tracking