Trk::PRD_MultiTruthCollection_p1::Entry Node1 Trk::PRD_MultiTruthCollection _p1::Entry + id + Entry() + Entry() Node2 HepMcParticleLink_p1 # m_mcEvtIndex + HepMcParticleLink_p1() + HepMcParticleLink_p1() Node2->Node1 +particle Node3 long Node3->Node2 #m_barcode