When I was buying SLRs I went for Canon which offered what I went for. Both Nikon and Canon share the SLR market almost to the exclusion of other manufacturers and their design and manufacturing capabilities are hardly taxed at this level so it really is a question of opinion.
Looking at the two competing cameras that you have suggested, I would say that the Nikon represents the better option for an entry level camera. It has a newer design kit lens and should you consider it in the future, the higher frame rate for full HD video would definitely be beneficial for moving subjects such as you will find with trains.
I also took a look at dpreview.com which is a reliable source, and found
this comparison also suggests that despite both cameras being good, the Nikon may be the better buy depending on the user's needs.
There is another optio which is to look for a decent second hand body and lens. I see that you are in Essex, so WEX whose London showroom is at Aldgate, should be easy to get to. WEX sell used equipment that they buy when customers upgrade, and although I've never bought any used cameras from them myself, I believe that they are inspected on receipt, have warranties and are a way to get a better camera for the same money. For example, the Canon 77D and 700D are both above the entry level 2000D yet they have a used body of each available for £377 & £205 respectively - see
here. Used lens are also available for Canon EF S bodies
here. Similarly, WEX also has used Nikon equipment that can offer a cheaper route to the next level range with little risk of buying a dud.
There are of course other sources of used cameras including Ebay, but that probably has more risk that comes with lower asking prices.
Hope this helps.