Steam & Excursion > UP 6936 smokes it up! Assisting 844 up Medbury Idaho 6/30/1990

Repost, but this time edited out bad part.
6/30/1990 Idaho Centennial special, Westbound, west of Hammet/Glenns Ferry, 4th of July weekend.
With 10 wheeler 1243 on flatcar display, behind 6936, plus a few CNW passenger cars in consist.
6936 had probably been idling for many days, and really smoked it up when called to help push this train
up Medbury hill in run 8 (?) I was pretty pleased with that sudden smoke, plus that wonderful sound of 844 and 6936 working
together at full throttle!

Jim Baker
Riverside, CA



Edited 2 time(s). Last edit at 07/05/26 12:04 by RailRat.

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The audio track is great - wonderful to hear 6936 in Run8 and 844 working hard together.  Thank you for sharing!

Steve Zahn
Broomfield, Colorado



Edited 1 time(s). Last edit at 07/05/26 08:11 by run8diesel.

Nice job Rat!

I have a hunch 844 could have handled it alone.

That's a spectacular location, and a very dramatic climb up from the valley below to the top of the lava mesas (?).  Really gorgeous.

What was the likely origin of the white smoke from 6936's second prime mover here?  As someone who has watched but never run/maintained diesel locomotives, this doesn't look like the normal exhaust behavior of a turbocharged EMD diesel that has been working under load for a while and is just being notched out a bit more, right? 

I've heard a couple of possibilities over the years for EMD's producing copious white smoke, but both seem a little far-fetched in a situation like this.   Do either of these scenarios ring true with the experts?  One is that the locomotive could have been idling for a while, building up crud in the exhaust manifold while the steam locomotive did all of the work, and now the diesel is called upon to help, the throttle is being notched out, and the "soup" in the manifold is heating up and boiling off out the exhaust.  Another even less likely scenario is that the second prime mover was actually shut down and cold when the train got underway.  For whatever reason, the rear engine has now been started and put online, and is blowing unburned fuel out the stack until it warms up and all the cylinders start firing as they should.  

Any other possibilities?

Evan_Werkema Wrote:
-------------------------------------------------------
> What was the likely origin of the white smoke from
> 6936's second prime mover here?  As someone who
> has watched but never run/maintained diesel
> locomotives, this doesn't look like the normal
> exhaust behavior of a turbocharged EMD diesel that
> has been working under load for a while and is
> just being notched out a bit more, right? 
>
> I've heard a couple of possibilities over the
> years for EMD's producing copious white smoke, but
> both seem a little far-fetched in a situation like
> this.   Do either of these scenarios ring true
> with the experts?  One is that the locomotive
> could have been idling for a while, building up
> crud in the exhaust manifold while the steam
> locomotive did all of the work, and now the diesel
> is called upon to help, the throttle is being
> notched out, and the "soup" in the manifold is
> heating up and boiling off out the exhaust. 
> Another even less likely scenario is that the
> second prime mover was actually shut down and cold
> when the train got underway.  For whatever
> reason, the rear engine has now been started and
> put online, and is blowing unburned fuel out the
> stack until it warms up and all the cylinders
> start firing as they should.  
>
> Any other possibilities?

Evan, here's a reply from Bob 3985 about 8 years ago when I posted same video.
Not sure if they needed 6936 between Cheyenne and Pocatello, doesn't really answer your
question, but it's possible 6936 had been idling all the way from Cheyenne?? 
(Note it's much more readable in desktop view mode)

Jim Baker
Riverside, CA



Edited 1 time(s). Last edit at 07/08/26 21:11 by RailRat.

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Thank you all for your replies!

Posted from Android

Jim Baker
Riverside, CA