This is a replacement roof for use with the Atlas 4650cuft ACF Centerflow covered hopper to model a car fitted with 20" hatches on ACFs standard pitch using the 13 support roofwalk and will work with both versions of the car.
To complete, you will require a set of 20" Round Hatches from Athearn's Blue Box Centerflow Covered Hopper.
Start by removing the roof, then carefully remove the roofwalk. The roof walk is attached with fold over tabs attached to the legs.these are best bent open with a flat blade screw driver. Straighten each leg with a pair of smooth pliers, then install the roofwalk on to the new roof. The roofwalk is a snug fit and only a small dab of ACC on some of the leg ends, do not fold over the leg ends.
This conversion is perfect for the DOCX SCLAIR car, Atlas models it with 30" round hatches, it should have 20". For the Sclair car, outlet hatches from the Atlas ACF 5701 covered hopper are recommended. Also, the contempory modeler needs to fit vented hatch covers in 3 positions, see: https://www.flickr.com/photos/lastarial/24467758530/