In what location am I on the Southern Region?

I am at a terminus at some location in the Southern Region, while it may not be a terminus for some, it is a terminus for many. If I removed the non-terminating trains there would be no reduction, but there would be an increase in some other way. From this location I can go places far and wide, as far as 300 miles away, although it may involve changing trains, but although I may not change the trains, I can still travel far. I can travel to the east, west and south, and all by changing once along my journey, but the question is, where am I?