I am modeling D&RGW diesels and have two Alco RS-3s to detail. The Rio Grande Alcos came with dynamic brakes, as evident by the full louvers on the short hood and a vent on top of the short hood. I have not found prototype photos or drawings that show the dynamic brake vent in detail. Most photos of the Alcos were taken long end forward, as they ran that way. Utah Railway had several Alco RSD4 units, which also had dynamic brakes. In 1994, Doyle McCormack restored and repainted ex-Utah RSD4 #306 as NKP #324, and it was leased to the Willamette & Pacific in Oregon. Does anyone know where this unit went from the W&P and who I can contact to get dimensions and photos of the Alco dynamic brake vent? Please contact me at railbass@home.com. - John Manion