At the onset of the Civil War the South had a rail network disjointed and plagued by changes in track gauge as well as lack of interchange. Locomotives and freight cars had fixed axles and could not use tracks of different gauges (widths). Railroads of different gauges leading to the same city required all freight to be off-loaded onto wagons for transport to the connecting railroad station, where it had to await freight cars and a locomotive before proceeding. Centers requiring off-loading included Vicksburg, New Orleans, Montgomery, Wilmington and Richmond. In addition, most rail lines led from coastal or river ports to inland cities, with few lateral railroads. Because of this design limitation, the relatively primitive railroads of the Confederacy were unable to overcome the Union naval blockade of the South's crucial intra-coastal and river routes.