The gear box of the Thirdrail Pennsy I1 Decapod is one of the better, slow running gear systems, in a larger locomotive, IMO. The first/front driver set, and the 4th driver set, are flanged, other drivers are flange-less, (blind drivers), to allow operation on small radius, O72 or less, layouts. The 4 axle trucks, on the tender, can also be a problem, on small radius layouts. Middle Shelf.
Right in this picture. Third rail, manufactured, the I1 Decapod, with a short tender as noted above. Thank you for the great pictures. Mike CT.