Contents: Summary; Food transportation bill; Transportation and marketing bills; Transportation bill for agricultural and related products; Recent trends in railroad and motor-carrier rates; General railroad rate level for selected agricultural commodities; Shipper costs and rail rates; Effect of recent rate increases on rate differentials; Effects of transportation costs differ from effects of most other costs; Interstate Commerce Commission sees importance of rate impact; Statistical evidence concerning effect of freight rates; Transportation charges and geographic wholesale price differentials—Idaho potatoes; Transportation charges and price spreads between shipping-point prices and wholesale prices—potatoes; Selective readjustments beginning; Appendix (Technical Notes Regarding Mathematical Basis for Estimating Effect of Transportation Costs Under Given Assumptions)