Refactor train_utils module

[jeipollack]

A review of the train_utils module revealed areas needing improving in terms of code quality. There are duplicated commands, hard-coded values and many nested-if statements.

Refactoring should apply the following:

• Moving duplicated commands and if-statements either to individual functions, or a dictionary of options with specific function calls, or strategy design pattern to handle the different settings
• Convert hard-coded values to options or remove entirely