I'm considering purchasing some inter modal cars. What height clearances ( top of rail) do I need for bridges and tunnels?
Thanks,
The N scale double-stacks I have are 1 9/16 in. high,railhead to top of upper container.You probably could get away with a 1 5/8 clearance (near paint scratching) provided the lower track is perfectly horizontal but a 1 11/16 (1/8 in. play) would be safer.If lower track at a somewhat steep angle,then I'd say tou need a 1 3/4 railhead to bridge deck height.
It's just barely under 2". If your clearances are a perfect 2", you'll never have anything to worry about.
Also keep in mind that some N scale intermodal equipment, such as the Walthers Thrall doublestack cars, ride extremely high off the rails, and when loaded with double-stacked high-cube containers, might give you clearance problems. I remedied this by body-mounting the couplers with MT 1023s and using the BLMA 100-ton trucks to replace the stock trucks. The BLMAs lower the car height and help with the clearance problem.
If you wanna get more involved, then file off some of the metal on the articulation joints to get it to a more prototypical ride height (even with the BLMA trucks on, the well bottoms are still too high off the tops of the rails).