Original sentence: It is most popular in the United Kingdom and the United States.Train spotting is a pastime practised in countries where trains run on a constant schedule, in which enthusiasts spend time at railway depots, train stations or at trackside vantage points noting down serial numbers of passing trains and locomotives
Edited sentence: Train spotting is a pastime practised largely in the United Kingdom and the United States (and elsewhere) in which enthusiasts spend time at railway depots, train stations or at trackside vantage points noting down serial numbers of passing trains and locomotives