I assume that you are asking this question in regard to the late 1800s. This was a time when the railroads were becoming the first really big business in the United States. There were many people at that time who wanted to regulate the railroads. This is because the railroads had the ability to hurt farmers. The railroads could charge the farmers really high prices because the farmers needed the railroads to get their crops to market.
Railroad owners, of course, did not want to be regulated. They did not want to be regulated because regulation would have hurt their profit margins. They could also argue that they did not want to be regulated because they believed that regulation was bad for the economy. They (like other of the “robber barons”) tended to believe that regulation reduced competition and that competition brought about a “survival of the fittest” situation in which the best companies prospered and thereby improved the economy.
For these reasons, a railroad owner would certainly have hated the idea of regulation.