The Bulge ?

At first I thought it was either a pancake antenna, or the base of a whip antenna...

 

But, after looking through "UP's Mighty Turbines", it looks to be the base of where the horns should mount... Where are the horns mounted on your units?

 

 

 

I hope this helps...

 

Thanks,

Mario

As with anything regarding railroading, it depends on what locomotive and when.  Here's the 20 in 1965 with the airhorns further back on the roof:

 

As I recall, the 18 at IRM also has the airhorns located back there.

 

Rusty

If the bulge on top of the cab is what you are talking about, then what Mario said is correct. Originally the horns were installed in this location but kept icing up, so they were relocated further back on the roof above a roof grid opening so warm air would blow on them while the locomotive was in operation. I expect the bulge is a plug. So, depending on the time frame both locations are correct for the horns.

 

Butch 

oh, ok!  Gotcha!  That's good to know.  I don't ever plan on being a UP fan, but their Challengers and Turbines do hold my attention.

 

Thanks,

Mario

Just my opinion, but I don't think that that "bulge" has anything to do with the air horns. If you look closely at the ends and top center of the "bulge", it appears to be some sort of ventilation arrangement, possibly for an electrical cabinet below.

I can't say for sure either HW.  I just know the horns were moved from the cab roof to the aft roof due to icing. I assumed the bulge was the old horn location.

 

Butch

Correct. All my color slides of UP operations from 1963/1964, show the horns moved rearward on the "Big Blows", yet that "bulge" was still present. Thus, I maintain that the "bulge" really has nothing to do with the air horns. That "bulge" is part of the carbody hood structure.

Well! this is interesting, you have found a Bulge that is other than the one I was thinking of, but still the same very interesting! Please continue! The one that intrigued me was above the cab side window in the roof area directly above the window. In the first Overland run this area of the cab roof doesn't blend in as in the pictures Iv'e seen of the Prototype, MTH seem's to have copied it and made it more pronounced. The second run off Overland models, model the roof area correctly.     Stephen    (cTr...Choose the Right)

Oh, I see!  I didn't even think that was out of the ordinary! Ha!

You've got me there...

Thanks,
Mario

Butch      I started a reply and the computer went down, so second try, I requested copies of drawings from UP a long time ago, they said their drawings for the 8500hp turbine were missing!!! oops. Overland wouldn't part with there's, understandable, so copying a good model is the next best thing I guess, the mistakes do multiply thou. Its possible MTH could correct at there next run, with added detail, you never knew.     Stephen     (cTr...Choose the Right)

Absent of facts we can all have our guesses. 

 

Being the fat cheeks are above the floor and forward of the door it affects only the cab.  Have you considered the extra width to be an early rendition of a comfort cab?  A well placed bump out could provide just the whatever space needed.  

 

Added width over the truck would have minimum impact on curve overhang.

 

Check out the Jeep critter parked in the lot adjacent to the big blow.

Iv'e checked all the photo's from turbines westward, and any others I could find, there's no sign of what we see in the models. The other explanation could be the drawings where done this way, but in practise the roof was  a smooth blending we see in the prototype.  Stephen    (cTr...Choose the Right)