Final answer:
Train operators primarily learn new regulations through formal orientation sessions that cover company policies, industry practices, and culture. This training often reflects oversight from regulatory agencies like the Interstate Commerce Commission.
Step-by-step explanation:
Train operators become acquainted with new regulations MAINLY through formal training sessions that include an orientation period. During this orientation, they learn about company policies, regulatory practices, and the overall culture of the train operation environment. Key sources of these regulations could be governmental bodies such as the Interstate Commerce Commission, which, as it gained power, became responsible for regulating railroads and ensuring that operators were aware of and compliant with new standards. Over time, these regulatory practices extended to ensuring safety measures and uniform operations across different railway networks, facilitating not only safety but also national unity and increased political power. Additionally, the application of regulations can have a significant impact on the train industry's practices, as they can act as informal trade barriers if they are excessively strict.