SD45 shrouds

[Nieuweboer]

What was the function of the shrouds on some of Southern Pacific's
SD45 locomotives. Am I correct in assuming that they were an experiment to prevent engine asphyxiation inlong tunnels, a problem that was solved by the SD tunnel motors?

[tigerstripe]

That's correct, the elephant ear shrouds were an attempt to make the radiators draw air from the bottom; and eventually lead to the development of the tunnel motors.

[rrinker]

Exactly right. The air at the top of the tunnels is hot, especally 3-4 units back from the head end. Standard EMD radiator ducts draw the air from near the top of the units. With this air already heated by the passage of the lead units, it wasn't able to cool the trailing units and they would often overheat and shut down. Not only is this hard on the engines, but if the remaining units couldn't pull the tonnage of the train you now had a train with a crew aboard stuck inside a tunnel with a bunch of large running diesel motors turning the air bad.
The elephant ears directed air from down low (cool air always falls). The SD45T design basically put the elephant ears inside with the radiator openings down low on the carbody.

--Randy

[SSW9389]

You can read about it here and a photo: http://espee.railfan.net/spsd45t-1.html

The "elephant ears" were applied to 12 SD45s as a test. The modification was also applied to three of the SD45X prototypes.

[CSSHEGEWISCH]

SP's SD45's weren't the only diesels with elephant ears, check these links:

http://gunzelgallery.fotopic.net/p25496565.html
http://gunzelgallery.fotopic.net/p25496566.html
http://gunzelgallery.fotopic.net/p24231957.html

Also note two bulldog noses on one locomotive!

[Anonymous]

In the March 2005 issue of Model Railroading, Bob Boudreau did an article on kitbashing a Canadian Pacific SD40-2 with elephant ear shrouds...

So ditto CP, I guess!