Hello everyone, I have another interesting question for you all, on all of SP's SD7R/SD9R's there is a rounded (follows the contour of the cab roof) box directly behind the cab on the long hood. What was it for and what they housed? I have also noticed that they range in size from (what looks like) about 1'- 2 1/2 feet. Can anyone tell me why they had them, it appears they got them after rebuilding under GRIP. Thanks for any help!
Andrew, that was a piece of sheet metal to keep water from running down between the cab and carbody and ruining the electrical components. Before the rebuilding, it was found that water was getting in between there, so these were added. Here's one I added to an SD9 of mine.
Thank you so much for answering my question! I thought it probably had something to do with radio equipment or something...shows you how much I knew! LOL This makes me think of another question I have, on most of SP's SD9's and GP9's they had a large box located several feet behind the cab on the long hood just before the dynamics...what was it for? Thanks again and any information is appreciated!
Regarding the box for the paper air filter, noe all GP9's and SD9's had them. The first upgraded units kept the oil bath filters. The units upgraded near the middle of the GRIP program got the box for hte filter. The later units had the paper air filter inside the hood. Be sure to find a photo to be sure your unit had the box. The GP9's had the access door on the fireman's side while the SD9's had it on the engineer's side. To my knowledge none of the SD7's got the filter box. The photos are from Nor-Cal Espee Connection and show the filter boxes.
Thanks for all the information! I knew that not all GP9/SD9's had them and I know that I have never seen a SD7R with one. I've also noticed that when they added the "water-proofing" piece they also removed a bolted-on plate that was near the same area. Thanks again for all the information!
The sealed carbody had more to do with keeping out dirt and dust, which could foul electrical components. Having a sealed and pressurized carbody, and a centralized air filtration system helped achieve this. GE's U25B was one of the first to pioneer this, and EMD's competing GP30 had the sealed carbody and inertial air filtration system as a selling point.
Did the "sealed" car body mean that it had positive pressure in the long hood? Was that later? Do modern railroads ever run with the doors open for cooling or something? Thanks. Now there's some good modeling info. :thumbs_up:
Yes, there is positive pressure in the long hood. I have run GP9's with the doors opened for cooling before. But thats only because I couldn't keep the shutters on the intakes opened.
On BNSF we are not supposed to run with the hood doors open, they tell us it will accualy make the problem worse. Kevin
