Results of a numerical simulation, based on an energy consistent moving singularity dynamic finite element procedure, of fast crack propagation and arrest in a high strength steel DCB specimen are presented. The influence of material properties of high strength steel on dynamic crack propagation and arrest is investigated. The influence of the loss of constact of specimen with the loading wedge is also critically examined. The present numerical results are compared with available experimental data. It is found that the present results agree well with available experimental data, and the crack arrest toughness values obtained in the present analysis correlate well with the ratio of the maximum kinetic energy of the specimen to the input energy.