O Scale Model! For the O Scale folks, these PRR Style pneumatic switch machines make a great lineside detail for your Layout. Set includes four left hand and five right hand machines. Combine these with the O scale version of Keystone Details Pneumatic Air valve for extra detail:
https://www.shapeways.com/product/XMKD9Q8JZ/quot-o-quot-scale-prr-air-valve-for-switch-machines?li=user-profile&optionId=58956980