Slaves on the rear, and not a cracker box in sight

[E.M. Bell]

Many moons ago, it was not uncommon at all to see a Southern train (and even early NS) with Slave units and Cracker boxes. (Which was the Southerns unofficial definition of radio controlled, mid-train helpers, with a "cracker box" which was the special car used to link the mid-train units to the head end)

Over time, it seemed this practice fell out of use for various reason, but is making a come back in a more modern form, the 'DPU" or distributed power" DPU works pretty much the same way, with the exception of the need for a radio control car, as the new power has all the DPU equipment built right in.  While a lot of the Western roads have been using DPU for some time, its seems to just now be catching on with the NS.

For the past year or so, the only DPU trains we saw on the CNO&TP or Louisville district with the handful of coal trains that run on a As-need basis. In the past few weeks, this has expanded to a couple of the longer intermodal trains such as 23G and 22A.

I had a chance late Saturday afternoon (01/15/11) to get a couple of shots of the 22A as it made a very late trip across the Louisville District. The concept is the same, but for someone like me who grew up watching those slaves and cracker boxes roll through town on a regular basis, its sure looks different!  

Here are a few shots of the 22A, NS 285 with a EMD duo, and a quick look back at how it used to be.. Larger version can be found here at this link,   http://www.pbase.com/kd4jsl/nsls11eb

First, a look back.. NS 112 rolls through Lawrenceburg KY in 1990, with a SD40-2 still in Southern Paint, and a radio car. It sure would be nice to go back....



Another look at the old school, again at Lawrenceburg KY in 1991



and now the modern day way. NS 22A takes the siding at East Talmage KY, with a DPU on the bottom, while 285 holds the main.





And NS 285 with a SD60M and a CEFX lease unit leaving Talmage after the meet, and just minutes before the sunset.

[blacksheep]

i talked to a ol SR man years ago about slaves and he was saying the SR found they worked better 2/3's back in the train. sounded like the lead units would vent the first 1/3 and the slaves would vent the back 2/3's when they used train brakes. now it's the 21'st century and they don't train the crews (or want them to) to use air brakes so they just stick a unit on the back. gotta be cheaper than switchin one in the mid train spot.

[E.M. Bell]

Ah yes, back when you didn't get your hand slapped for touching the automatic brake for anything other than coming to a dead stop. With the train handling and air brake rules what they are now, it really makes me wonder what a new engineer would do if they had a train with less than optimum dynamic brakes and HAD to use the air to control the speed...just stop every time you made a set??

The slave units where good for helping to "pump up" a train, and also for getting the brakes to set and release faster. I really dont know a lot about how todays DPU stuff works, and have wondered in the past if the air brakes on the remote unit follow what the lead unit does, or if it us set up more like a car, applying and releasing with the rest of the train... Engines have a bad habit of sliding with a heavy set of air, so do they bail off when the lead units do?

[Ptrainman]

ECP DPU coal trains run where I am and when they start off they start right away and you don't hear any slack in the coupler. I would assume that means the head and rear bail at the same time. If they didn't there would be slack in the couplers wouldn't it?