The paths of the tracks are clean and straightforward - a welcome break from the complexity of other modules. But the addition of water (perhaps a canvas print, digital photo, or laminate with an acrylic finish) and a long bridge add a visual focal point. A lighthouse, partially submerged ship, flashing buoy, wharf, cargo crane, and waterfront town could be featured as well. Perhaps even a simulated whirlpool...
The bridge could be a dramatic and custom element. A basic plate/girder construction is strong and simple, but I could imagine a swing, bascule, or lift bridge here too. For a truss or Warren bridge, use hardboard or apple-ply plywood faced with a digital print. A series of ‘concrete’ arches or 'cantilevers' could be made from dimensional lumber and surfaced too.
There is enough lead-in space to go underwater instead. Create a tunnel opening at each end and leave the side open and kids could shuttle the train under the bay itself.