In obtaining passage of the pure food and drug act in 1906, president theodore roosevelt would likely have encountered more resistance than the passage of the hepburn act because

Because the Hepburn Act strengthened existing government control of railroads.
The hepburn act gave united states federal law the right to set maximum railroad rates and extend its jurisdiction. This means that the taxation expense that had to be paid by the railroad companies would be significantly higher compared to the period before hepburn Act