SD40-2s

[fredswain]

The switchers in the yard near my house are typically older units. They've got 4 or 5 SW1500's, a GP-38, an SD-40-2, and a couple of old U boats. What interests me about the U boats is that the fuel tanks are removed. I have no idea why. They usually switch the yard with engines in groups of 3 or 4 and it's always a conglomerate. What is the reasoning for removing a fuel tank on an engine but having it coupled up to an engine consist for switching?

 

[CSSHEGEWISCH]

The U-boat shell is probably a remote control master.  UP has a small fleet of them in the UPY 100 series:  http://www.rrpicturearchives.net/showPicture.aspx?id=738635   They are coupled to locomotives that are not equipped for remote control in order to allow them to be used in remote control.

[fredswain]

That's exactly what it looks like. It's strange though. It's usually coupled in the middle somewhere (3 or 4 engine consist) and from what I have seen there is always an engineer. At least most of the time there is. I need to pay more attention.

[Railway Man]

SD40-2s were usually not built with heavy-duty power contactors because it was not contemplated they would ever be used for anything other than road service.  The heavy-duty contactors will tolerate a high cycle rate without burning or arcing.  Most GP38-2s, however, were equipped with heavy-duty power contactors, as are switch engines, because the GP38-2 was going to be a switch engine as much as a road engine. 

Other things besides weight and their habit of turning over rails on rotten ties on curves -- like you would find in an industrial spur -- that make an SD40-2 or any six-axle locomotive a poor choice for switching is that the FRA sets the maximum amount of wheel thickness variance in a three-axle truck at 3/4" (if I remember the rules correctly), whereas a two-axle truck has no such requirement.  Accordingly the SD40-2 has to have a lot more wheel truing, and because it has a stiffer truck, it's going to have more wheel wear, and thus will go through wheel sets a lot faster.

Rerailing six-axle locomotives, and dealing with that big truck in the shop, is also not much fun.

RWM

[Railfan1]

CSX has recently retired a few of the -2s and placed some into storage. I thought they were trading some of them in on the ES44AC(AH)s, but things must have changed.

[WP 3020]

Recalling some tales of 6 axle vs. 4 axle (1st gen EMD) from some Espee engineers, I remember one preferred the  SD9s over the GP9s because the GP lacked the extra breaking. Some spurs and branches required the lighter axle loading (weight distribution) of a 6 axle loco.

[BigJim]

I'm not an engineer so I'm just guessing.  I would think that the ability to load quickly is a major factor since that's needed for kicking cars when flat switching.

EXACTLY

[legsbluetrain]

Last week,I caught an SD40M-2 UP 2753.Yes,I said SD40M-2.That's what it said on the cab.I got it on video.

[silicon212]

The SD40M-2 is actually a rebuild from Morrison Knudsen in the 90s for SP.  It was inherited by UP in the merger.

It could have been built from an SD40, SD40-2, SD45 or SD45-2.  In any case, they are electrically and mechanically an SD40-2.

[WCfan]

Yep, some of the SD40M-2s that where rebuilt from SD45s still might have there "wings" on.

Wouldn't of MK rebuilt them to SD40-3 standards? As most of the rebuilt SD40s now are rebuilt with -3 standards.

[silicon212]

Although dash 3 was becoming available at the time, I do believe these (the SP units) were all dash 2 rebuilds.  1994, if I recall.