TM Terry posted:What is the function of the small car trailing the B6, about the size of a truck?
That is a Scale Test car. In order to verify the accuracy of railroad car scales, a known weight is placed on the scale to calibrate/certify the accuracy of the scale. Thus, those Scale Test cars do NOT even have brakes, as the brake shoes would wear and change the weight of the test car. Thus those Scale Test cars were/are normally carried on the rear of a train, since they have no brakes.
