The following (necessarily incomplete) list shows the majority of categories relevant to this WikiProject.
The following high-level categories are generally not used for individual articles as more appropriate subcategories can be found within them:
These are subcategories of Category:Rail transport in the United Kingdom:
These are subcategories of Category:Railway companies of the United Kingdom:
These are categories from other areas that have also been used by articles within the scope of this project:
These are subcategories of Category:Locomotives. Most are also subcategories of the appropriate company categories listed above.
These are subcategories of Category:Rolling stock:
These are subcategories of Category:Rail transport in Great Britain:
These are subcategories of Category:Railway stations in England:
These are subcategories of Category:Rail transport:
These are subcategories of Category:Rail transport in Great Britain:
These are categories from other areas that have also been used by articles within the scope of this project: