What is the fine-grained topic of the following text: Charles “Pretty Boy” Floyd and other notorious outlaws who used the rugged and inaccessible Cookson Hills to hideout in the 1930s would surely marvel at the four-lane interstate highway, the diesel trains and the barge traffic on the Arkansas River that now connect Sallisaw with the world. Only return the topic.
Development and modernization of transport in Sallisaw since the 1930s.