The route between Shoeburyness and London Fenchurch street would be a nice route to drive. The route has a nice variety of directions such as directions via chafford hundred and also directions via Dagenham docks, and gives good views. C2C use both the Class 357 Electrostar as well new 5 Carriage 720.
This would be a fantastic addition to TSW, offering a really versatile route. It could also include the option to hop at Barking for the Overground, and if the Liverpool Street branch were included hop at Stratford as well. It would also fit perfectly alongside a potential GEML release, since you could routeāhop at Upminster to Romford to connect with the GEML.