Where a state statute prescribes maximum intrastate railroad rates and also attaches heavy penalties for violations of the statute by a railroad or its agents, and where a railroad thinks the rates are confiscatory and hence unconstitutional, it is faced with an apparent dilemma. Must it either submit to the supposed confiscatory rates or else run the chance of incurring heavy penalties in case the statute is held constitutional? Or, is there another alternative-a painless way of testing the validity of the rates?