I propose an extension for the new PDL so trains can go via Winchester and Eastleigh, and then go down through Botley and Hedge End. I (and I'm sure many other simmers) would love this extension, and it is the 15 extra stations added to the route. I think this would be a worthy development.
"Only" 15 stations is an understatement. It all depends on the length between the stations, how often trains stop at the stations and so on.
What about an extension from the Portsmouth Direct Line: London Waterloo to Portsmouth Harbour this could just be like what happened with North London (& Goblin) Lines, North Wales Coastal and South Wales Coastal getting additional extensions.
I don't think so. Just Trains have done the entire length of the western mainlines from Paddington to Penzance (as three joined up add-on packs) and you can drive the entire route (in one big session, if you've got time!), it's over 300 miles. The game can handle it fine.
Hasn't someone merged all the east coast routes? So it proves it is perfectly possible as long as the game on 64-bit edition!
Yeah, it’s WIP on ATS and is around 395 miles not including the extensions to the routes they merged (such as Royston) but there are also plans to include SECML taking it to around 450 miles long.
The route length makes no difference. Map tiles load and unload. Map tile density (how many buildings and smaller assets that are needed to be loaded and unloaded) cause issues and consists of course