Today there are numerous scources for obtaining model locomotives.They come in ready to run form from various manufacturers or in kit form and can be found in new or used condition and in built or unbuilt form.
If like me you like all steam locos then the supply is endless and collecting can be great fun.you may like to try kit building for eg. this provides a lot of enjoyment on completing a model of a real historical engine because you will need to have done the necessary research into the prototype say from books and photographs to place the loco in the correct livery and condition at a certain period in history.Most locomotives were continually altered throughout their working lives so if you want accuracy then there is no substitute for research and photos are paramount.Even books can be wrong about certain details such as wether a loco ever carried a certain livery but if you find a photo you have cracked it.
Needless to say in time you will become something of an expert in this and when you see a black five painted red or a great western star with outside steam pipes in the wrong livery you can say these never existed.The internet is a great place to find info
So why not have a go at this interesting hobby
Johnson Single in Midland Railway livery built from a kit and painted with precision paints still available and lined out with HMRS pressfix lining
These kits though no longer available still appear for sale on ebay or at swapmeets