While BLW will be a separate system, it probably will have a rail connection to UP on a spur off its line in NV. That'll be needed to deliver things, at least. And if trains will be interoperable with CAHSR (if they both, someday, meet in Palmdale) they can't be *too* wide since CAHSR has to be able to use Regular Railroads like Caltrain and Metrolink in terminal areas. Also, BLW is standard gauge track like almost everything else (except BART of course). So "longer lower wider" has limits .