question about Otto Perry Picture of 463 *PIC*

I was poking through the Devner Libraries collection of Otto Perry pictures, and had a question about one. I'm including the summary info and call number in case somebody else wants to look at it. The URL is [gowest.alliance.org], but you have to negotiate to their search page and enter "OP-7592" to get this picture. In any case, my question is about the funny pipe sticking up off the steam dome (?)... i've circled it in the image below. Plus, check out the snow plow -- pretty impressive.
---
Title: D&RGW locomotive (Narrow Gauge), engine number 463, engine type 2-8-2
Call Number: OP-7592
Summary:
Three-quarter view of left side of engine, from front end, has wedge plow. Photographed: Durango, Colo., August 13, 195