There is no attempt to model real stations, or a real track plan. There is a short spur going to the 'Scollay Square' station, and a pair of staging/storage tracks which I built the 'South Ferry' station around.
The track plan is a simple loop, with one passing siding at the 'Penny Lane' station. My subways run beneath the 'normal' layout on the surface. I model subways in HO, using the Proto 1000 subway trains.