[en] This Preliminary Design Report presents the results of General Atomics' (GA) preliminary design effort to develop legal weight truck From-Reactor Spent Fuel Shipping Casks. The report consists of a design description, preliminary drawings, and the results of the structural, thermal, containment and nuclear evaluations that support the design. Also included are the results of trade-off studies in which we considered the effect of changing several basic parameters on our baseline design as required by the contract. Our engineering test program supports the selection of the neutron shield material and the honeycomb impact limiter design. The design report also includes preliminary drawings and a structural analysis of a semitrailer designed specifically for the GA-4 cask. 24 figs., 1 tab