What term is used to describe the section in the Division Timetable that categorizes locomotives?

The term "Diesel unit groups" is used to categorize locomotives in the Division Timetable, particularly focusing on the distinction and organization of diesel locomotives based on their functionalities and specifications. This categorization is essential for operational efficiency, as it allows for the quick identification of the types of locomotives available for service and helps in planning and scheduling based on their capabilities.

The other options, while related to locomotives, do not represent the specific terminology used within the context of the Division Timetable for the purpose of organizing diesel engines. "Locomotive classifications" might seem relevant, but it lacks the specificity of "Diesel unit groups" as it could encompass various types of locomotives. "Engine types" could refer to general categorizations that include steam, electric, and diesel without focusing specifically on diesels. "Railroad categories," on the other hand, typically refer to broader classifications of operations or networks rather than the specifics of locomotive organization.