An apparatus which includes a housing defining a chamber, the chamber being sealed from an exterior of the housing, wherein the housing further defines an opening in fluid communication with the chamber and the exterior of the housing. The invention describes a system of automated self-powered rail cars operating independently to transport material such as ore from a work face in a mine or cargo from a marine port to a major transportation hub. A control unit allocates uplink resource allocation information and downlink resource allocation information to a PDCCH which is arranged in each of the plurality of downlink unit bands, and allocates a response signal to the uplink line data to a PHICH which is arranged in the same number of downlink unit bands from the plurality of downlink unit bands as there are uplink unit bands. The metal silicide is reacted with the layer of metal to form a composite structure. Synchronizing can include transferring updated interface variable values, which are shared by the second modules and at least a subset of the first modules, between the serial simulation engine and the concurrent simulation engine.