Load Test Unit from CSX

Hi all,
my question belongs to this photo:
http://www.railpictures.net/viewphoto.php?id=235765

What's a load test unit and its task?

Did they install locomotive parts (prime mover, radiators, air system, ...) inside this "dummy" loco and test these parts, the engine itself remain stationary ?
So the generator doesn`t feed the traction motor, the electrical power went over resistors into a big water tank, for example.

Or did they hock these load test unit behind an overhauled engine and send them both on a test run.
And these load test unit provides dynamic brake performance to simulate load ? Similar example: http://www.railpictures.net/viewphoto.php?id=232906

Bye

heres an answer

http://www.railroad.net/forums/viewtopi ... ht=#399292

A load tested unit can be done two different ways. The 1st and eaisest way is if the unit is equipped with Selfboard Load. Selfboard Load is when you load the Main Generator into the Dynamic Braking Resistors on the Locomotive itself. This is a good quick way to see how your locomotive is preforming. You can go out and check the Governor Quad to see if it is running whatever the governor is stamped and the to see if the load regulator is in the proper position. The 2nd way to Load Test a Locomotive is to hve it hooked to a 17EM99 Load Test Box. There is 10 different steps you can put the unit in by changing the resistance of the load box that you are loading into. It can simulate running at a Higher Speed which would be in step 1 on the Resistance Scale which would give you a lot of voltage and not that many amps. If you are loading a SD40-2 you will have to pull out the TR11 or TR12 Module when loading in Steps 1 thru 3 on the Resistance setting. Agood normal setting to set your load box is in Step 4 or Step 6, that is very normal operating conditions. If you put the resistance box in step 10, that is simulating a hard load. In step 10 you will be runinng around 200 VDC and depending on if you are loading a SD40-2 your amperage setting will be close to the AR10 output level of 4698 amps and if it is a GP40-2 and a GP38-2 your output will be getting close to 6264 amps. Also when hooked to a 17EM99 load box, some of them can be equipped with the circuits that can enable you to calibrate a locomotive by putting it into open circuit for setting voltage limits and putting the unit into short circuit by setting the current limits.