diff --git a/Simulation/ISF/ISF_Fatras/ISF_FatrasInterfaces/ISF_FatrasInterfaces/IPhysicsValidationTool.h b/Simulation/ISF/ISF_Fatras/ISF_FatrasInterfaces/ISF_FatrasInterfaces/IPhysicsValidationTool.h
index d97e3f9c1f3d4c2c510c33c9acfcdd2cf45bcf7b..56d2d8cce44675582a50d0d2689f602e2a260bad 100755
--- a/Simulation/ISF/ISF_Fatras/ISF_FatrasInterfaces/ISF_FatrasInterfaces/IPhysicsValidationTool.h
+++ b/Simulation/ISF/ISF_Fatras/ISF_FatrasInterfaces/ISF_FatrasInterfaces/IPhysicsValidationTool.h
@@ -46,19 +46,19 @@ namespace iFatras {
     static const InterfaceID& interfaceID() { return IID_IPhysicsValidationTool; }
     
     /** ISFParticle info: old transport tool */
-    virtual void saveISFParticleInfo(const ISF::ISFParticle& isp, int endProcess, const Trk::TrackParameters* ePar, double time, double dX0 )=0;
+    virtual void saveISFParticleInfo(const ISF::ISFParticle& isp, int endProcess, const Trk::TrackParameters* ePar, double time, double dX0 ) const = 0;
 
     /** ISFParticle info: new transport tool */
     virtual void saveISFParticleInfo(const ISF::ISFParticle& isp, const Trk::ExtrapolationCell<Trk::TrackParameters>& ec,
-				     Trk::ExtrapolationCode ecode )=0;
+				     Trk::ExtrapolationCode ecode ) const = 0;
 
     /** ISFParticle info: new transport tool */
     virtual void saveISFParticleInfo(const ISF::ISFParticle& isp, const Trk::ExtrapolationCell<Trk::NeutralParameters>& ec,
-				     Trk::ExtrapolationCode ecode )=0;
+				     Trk::ExtrapolationCode ecode ) const = 0;
 
     /** Interaction vertex info */
     virtual void saveISFVertexInfo(int process, Amg::Vector3D vertex,const ISF::ISFParticle& isp, Amg::Vector3D primIn,
-				   Amg::Vector3D* primOut, const ISF::ISFParticleVector children)=0;
+				   Amg::Vector3D* primOut, const ISF::ISFParticleVector children) const = 0;
   };
   
 } // end of namespace