I've had/still have several cameras over the years, both for home security and trains. To monitor the hidden ramp I have a fixed 'bullet' camera; in the shed, a remotely controlled tilt and turn. I prefer wired but nowadays ones which use the home wifi are easier to install. There is a huge choice out there and usually you get what you pay for, but also pitfalls, for example you don't need those that insist on a paid cloud storage solution and some cameras can only be viewed through specific software on a mobile device and cannot be streamed to a PC. I find the older or cheaper cameras do suffer from wifi lag, especially when actually looking at a moving train, which is not what you want.
Based on my good and bad experiences, I would suggest a good mid-range outdoor camera, mains powered,
provided you have a strong home wifi signal at its intended location, then you can use a mobile phone to monitor and control it via the same wifi network, or even away from home via your provider network. My most recent camera from Amazon is this one (
Aosu CCTV Camera) and it is genuinely streets ahead of anything else I've used: easy to set up out of the box, has excellent app software (no subscription), is reliable, controllable, is smart (ie can pan to track movement), works well at night too (IR and floodlight), and is great value, especially if you can get it with Amazon's current deals. Most importantly, I find it has virtually no wifi lag, so would be great for railway monitoring, though as I say, a good signal strength is vital.