This is an interesting video but it does not reveal the details of what is going on. Is the loco sitting on a dynamometer? Seems like quite a technical problem.
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@hokie71 posted:This is an interesting video but it does not reveal the details of what is going on. Is the loco sitting on a dynamometer? Seems like quite a technical problem.
No "dynamometer" is needed, as the prime mover, i.e. diesel engine , is what primarily requires "load testing". Modern diesel electric units are equipped with a "self load-test" feature, where the electrical output from the main generator is connected to the dynamic brake grid resistors. Thus, the prime mover can produce full horsepower, without moving the unit. From memory, the "self load-test" feature became readily available in the early to mid 1970s.
Wow, that is impressive, I had not thought of the capacity of those resistors. at 746 watts and 4400 horsepower, we have about 3300 KW and we can boil a serious amount of "HOT Water" here. 
Is anything extra done to help dissipate the heat during these tests - Nothing is visible in the video.
Based on Hot Water's insights, I did find this video that shows the resistors glowing in operation.
They do sometimes glow. We had self load on the SD-50's and I saw it on SD-40's as well. Locos without dynamic brakes used a grid mounted next to the tracks but you had to run cables to it which was a pain.
At the factory we used to pull a unit in DB on the test track, that way you tested the traction motors too. One person in each unit, back and forth, switching from DB to power. All night.
I take it this contraption is a "portable" load tester?
Rusty
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Could be, looks like the front end of an Alco? All your need are the brake grids, an old loco could certainly provide that. It tests out the engine and generator but not the traction motors or transition, direction, or other contactors and wiring. So it's mostly for after an engine or generator rebuild or major work.
@Dougklink posted:Could be, looks like the front end of an Alco? All your need are the brake grids, an old loco could certainly provide that. It tests out the engine and generator but not the traction motors or transition, direction, or other contactors and wiring. So it's mostly for after an engine or generator rebuild or major work.
Not an Alco. That is/was an EMD export unit hood arrangement, converted into a portable load box, for use by the EMD Engineering Dept.
Also, as a former EMD employee, you of all people should know that EMC/EMD never used dashes between the model designation and the model series number. Thus, it is SD50/SD40 and NOT "SD-50" nor "SD-40".
I didn't spend more than a week at the plant, it was all travel and ojt. Yeah now that you mention it that does look like an export unit, l delivered GT26CWs to Morocco in the mid 80's but as I recall they were set up differently. Wish I hadn't gotten rid of all my factory manuals years ago. But I don't remember seeing that load cell in my brief time at the factory, I mostly saw what the rail shops had since that's where I worked. And many apologies for the heinous crime of the unneeded hyphen, I'll try and remember to leave it out in the future.
Did you work for EMD?
@Dougklink posted:I didn't spend more than a week at the plant, it was all travel and ojt. Yeah now that you mention it that does look like an export unit, l delivered GT26CWs to Morocco in the mid 80's but as I recall they were set up differently. Wish I hadn't gotten rid of all my factory manuals years ago. But I don't remember seeing that load cell in my brief time at the factory, I mostly saw what the rail shops had since that's where I worked. And many apologies for the heinous crime of the unneeded hyphen, I'll try and remember to leave it out in the future.
Did you work for EMD?
Yes. I retired at the end of 1998, after almost 37 years (started June 1, 1962).
@Rusty Traque posted:I take it this contraption is a "portable" load tester?
Rusty
What’s a brake sled? Something similar, or vastly different?
Also, I’m not sure if this fits the topic. Conrail had an ex-EL SDP45 that was numbered Q1. NS has it now. I think at one point CSX had something similar with a former CRR SD-something. Why do NS and CSX need large SD-platforms, but EMD used a switcher frame that looks half unused?
@Sam Jumper posted:What’s a brake sled? Something similar, or vastly different?
Also, I’m not sure if this fits the topic. Conrail had an ex-EL SDP45 that was numbered Q1. NS has it now. I think at one point CSX had something similar with a former CRR SD-something. Why do NS and CSX need large SD-platforms, but EMD used a switcher frame that looks half unused?
The Conrail SD45 test bed was/is for testing rebuilt diesel engines at Altoona. I think NS has an old GE Dash 8 there for testing GE engines.
Hot water or Dougklink
Would either of you be able to tell me where I could get a wiring diagram for an EMC/EMD Model 40 switch engine. I would like to rewire this antique but the books got stolen years ago and I have never found replacements.
@CSX FAN posted:Hot water or Dougklink
Would either of you be able to tell me where I could get a wiring diagram for an EMC/EMD Model 40 switch engine. I would like to rewire this antique but the books got stolen years ago and I have never found replacements.
My only suggestion would be to write a letter to the folks at Progress Rail, a wholly owned subsidiary of Caterpillar, and explain your situation. I have no idea what remains of the EMC/EMD historic Engineering Dept. records.
The Army and the Navy each had some. Perhaps there's a TM (technical manual) available through DoD archives. TM's are public domain, due to their being govt docs, and the DoD never throws anything away, unless it's something you need. You would need to know the DoD NSN (NATO Stock Number) to be able to search for the manual.
Within the military surplus hobby, there are dealers who collect and specialize in TM's. Try a Google search. Also, the Steel Soldiers site, populated by guys who collect big green trucks, might be a source.
Portrayal Press used to sell all sorts of military vehicle manuals, you might see if they are still around and could help you. With all the changes EMD has gone through I doubt they have any continuity left in documentation.
Also, if you Google the model # you'll see the other (possible) owners of the Critter. Those folks may have saved some documentation, too.
