73" rim diameter

The Trainz SKU for this item is P12401233

Special Features: Accurately detailed diecast metal construction

so you can see in the tunnel passage into that)

The Trainz SKU for this item is P11417284

Woodland Scenics ST1484 HO River Pass Layout Kit ProductID_11439170 73" rim diameterContains all the foam products needed to build a 4x8 foot terrain base. It includes Risers, Inclines, Profile Boards, Foam Sheets, Plaster Cloth and Track Bed, plus four Tunnel Portals and eight Culverts. Savings is 20% over items purchased separately. Once you build this terrain base, you have the knowledge and skills to build any layout. Click the button for details. Condition: Factory New (C 9) Operational Status: Functional Original Box: Yes (P 9)