The connector size is a remarkable 1/8 square

Vehicles and Figures not Included

The Open Deck Bridges include Bridge Flex-Track while the modeler's regular ballasted track runs across Ballasted Track Deck Bridges

The retaining walls are made out of Hydrocal

Here is a Atlas 20003684 HO Lehigh Valley Cupola Caboose #95016

Broadway Limited 4230 HO Burlington Northern EMD SD7 Paragon3™ #6004 DwDetails-1.90-1.40-9.00-5.00-5.00-1 The connector size is aThis is a Broadway Limited 4230 HO Scale Burlington Northern EMD SD7 with Sound& DCC Paragon3 #6004 (Cascade Green, black, white). Features: New Paragon3 Sound & Operation System Featuring Rolling Thunder with Authentic Sounds and Prototypical Operation in both DC and DCC environments, Factory InstAlled Engineer Fireman Figures, Variable Puffing Smoke Intensity and Timing, Locomotive Composition: ABS Body with Diecast Chassis, Couplers: (2) Operating