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Dislocation core structure, critical resolved shear stress (CRSS) and mobility of ½<111> screw and edge dislocations in BCC Ta-8%W alloy was studied using molecular statics and dynamics simulations at 5 and 300 K. Two EAM potentials are available to study the Ta-W system - Johnson-Zhou and Chen potentials. Both potentials give good estimates of edge dislocation mobility in Ta and Ta-8%W. However, the Johnson-Zhou potential predicts a considerably higher CRSS for screw dislocations in pure Ta as compared to experiments. Thus, only the Chen potential is used to study solid solution strengthening in Ta-8%W alloy. The CRSS for Ta-8%W alloy with Chen potential was estimated to be 600 MPa and 300 MPa for screw dislocations at 5 and 300 K, respectively. Edge dislocations exhibit twinning-anti twinning asymmetry in CRSS given the asymmetry in atomic disregistry and dislocation misfit across the …