What is this?

[mattmason]

I thought either power reverse or brake cylinder. Anybody know?

It’s a solid casting.

[jcbrock]

Westinghouse type KD brake cylinder is my take. The thing on the end of the reservoir would be the attached triple valve.

[VO4454]

Matt, It is a Westinghouse brake cylinder, resivoir, triple valve assembly as Jc Brock says. Check this link for some photos, scroll to page 4.

https://www.nmra.org/sites/default/files/d9o.pdf

Vic

[jcbrock]

Whoops, believe that is a KC not a KD - that's what I get for posting in the middle of the night. A little research indicates the "C" is for combined and the "D" is for detached, referring to the triple valve and reservoir.

[makinsmoke]

Wish someone sold them as dummy castings at minimum.

[cbrew]

Wish someone sold them as dummy castings at minimum.

I made one out of scrap and hide a clippard cylinder inside,

[Fender]

Wish someone sold them as dummy castings at minimum.

I see a non-operational rp version on the shapeways site in 2.5 scale. Go to www.shapeways.com, and look at marketplace->miniatures->trains->freight wagon, and search for “westinghouse”.