What is the source of steam emitted next to the exhaust stack and numberboard in this photo?

A friend from school is curious, and now, so am I.

Two different individuals have informed me it's exhaust from the air compressor.

They must have added that, it used to exhaust thru the smoke stack thru the smokebox, perhaps the recent overhaul caused this.


I wonder as the exhaust could cause a backlash in the smoke box and the fire heating and smoke. Probably a smart move.

I also appears they used some type of muffler arrangement. I have seen a few locomotives whose compressor exhaust does not go through the smokebox and it is quite loud.

The device appears on NKP Berks from their in service days.

Rob

Indeed. I remember the external air pump exhausts on 759 back in the day. It was often audible over the track noise when the engine was drifting at speeds under 30 mph. It was much louder and sharper (as I recall it) than the sound of an air pump exhausting into the smokebox.

Speaking of 765, I'm curious as to why the numberboards have C&O style numerals in them instead of what I was used to seeing on NKP engines?

The numberboards in C&O style reflect the "as-built" condition of the 765. The Chesapeake and Ohio and Nickel Plate had common ownership until 1947.

The NKP style numerals will return next year.

Big steam is not my personal favorite, kind of prefer smaller logging/mining or mid size locomotives. But I must admit this is one awesome locomotive, great picture. Sure would get my blood pressure going if I was standing next to it. Thanks, John.

The 30" 2-8-0 I worked on had it's exhaust routed internally, was originally an exterior with a muffler. Made it very tough to fire, every time the compressor hit it was like a birthday candle at a party. Not sure if that would effect a locomotive this large but there is a reason to design I've found.

Kelly -

And the Mars light too?

Les

The mars light was tested and restored worked over in its original restoration.
It was a decision to give it the as built appearance.

Just as a subthought I wonder if giving the engine a 767 look and celebration as this is the reason for 765's survival.

That is where the air compressors exhaust, and it goes through a muffler so it is not so loud. It makes a more pleasing muffled sound, Striaght air compressor exhaust is loud.

Here's my walk around video of NKP 765 all steamed up at Alma College during the SRI's fall Alma Special trip:

Nickel Plate Road 765 (Steam Locomotive Tour), 10-23-2010
http://www.youtube.com/watch?v=xO7rBrfG8AY

Enjoy! ^_^

You can see the 2nd steam exhaust working here.

Is there any specific reason why the air compressor exhaust would be vented in this fashion? From a engineering, operational, or maintenance point of view.

I have found the air compressor exhaust to provide a convenient slight draft on my fire while a locomotive is still. However, if it's exhaust is not vented through the smokebox this air compressor induced draft should not exist.

My initial guess is outside vent eliminates a pipe from the hot, particulated environment of a smokebox.