Hello All,

As the Subject suggests, I'm interested in a wiring diagram for a GP9. I've seen the one in the back of the Operating Manual, but that one isn't detailed enough. I'd like to have one which will tell me where the wires go, from the terminal block, within the base of the Control Stand.

We have the former Norfolk & Western #675. It was built with two control stands. When we acquired it from Consolidated Coal Company, all of the lights worked. Within a short time, a small fire destroyed some of the wires in the cableways under the cab floor. The wires between the two control stands were definitely affected, and possibly some of the wiring to the rest of the locomotive. A repair group came in, and repaired the damage. Spliced in a lot of new wires, and whatever else. And everything was supposed to have worked when they were finished. This was all several years back.

Since then, some of the lights have ceased to work. Bulbs have been replaced, but still nothing. The headlights on the short hood work, which are the most important, but the headlights on the long hood don't, and various things like step lights, and some of the lights inside the long hood, don't work.

The controls of both Control Stands work, it's just the lights which don't. We understand that the two stands are wired in series, but even when both switches are 'On' for a given light, it doesn't work.

For the Rear Headlight, I'd like to test the wires which run to the light, to mark those off the list of possible causes. However, there are two terminal blocks in each Control Stand, with none of the terminals labeled. The newer, replacement wiring is labeled, but none of them correspond to the labeling of the headlights. The older, original wiring is labeled, but it's unreadable.

Surely there's a diagram available somewhere, which will prevent me from having to disconnect each terminal in order to test them individually.

Thank you,

James Hinman

James,
Wish I could help you, but since you mention the new wires are marked but not per a diagram you have, have you contacted the group/person that did the repair? They may have made a job diagram and there is a good chance that they traced the wires going through that conduit.
Rich C.

Rich,

The new wires are marked, but they don't mean anything to me. None are marked the same as the wires which connect to the rear headlight.

Not all the wires were replaced, just some of them. The markings on the original wires are illegible.

James

If you are seeing an odd combination of lights not working, try checking the negative side of the lighting circuit. On typical GP9 installations, the platform lights and four of the engine room lights are fed by three separate switches on the positive side of the lighting circuit, but they all share a common string wired return circuit on the negative side. These eventually feed on string wire "NL" to the negative side of the master switch for all the lights. A loose connection in the negative string can knock out a combination of lights that are seemingly unrelated.

The headlight that is out could be a completely unrelated problem, on the positive side of the headlight circuit, both bulbs share the use of the 5 ohm multi tap resistor and the circuit breaker. Any loose connection or an open resistor at that point in the circuit will affect both bulbs. The two bulbs also share the same negative return wire.

As far as schematics are concerned, two possible choices are to contact Progress Rail and Norfolk Southern. Maybe you get lucky and one of them has the schematic.

PC

Contact the N&W Historical Society, they have several GP9 prints in their archive. Steamtown has a single control stand GP9 (ex NKP, N&W)and I can get you a copy of it if you feel it might help. PM me.
Mike Tillger

Low voltage Direct Current troubles on aged (rusty) equipment is notoriously subject to poor electrical ground connections.

Positive, or Negative ground. It doesn't matter.
If the electrical system has faulty, poor ground connections, it's not going to fully function.

Loose (rusty) connection studs, poorly crimped lugs, and so on... all contribute to the reason electricity doesn't flow.

The grounding connection points need to be established first.
From there, an electrical diagram will become most useful.

John

There should not be any ground(s) of any kind on the locomotive -- ever. From what I've seen over the years the only device that is wired to ground in a loco is the ground relay and that connection exists to sense a ground elsewhere in the system. Maybe on your automobile what John says is correct, but not your locomotive.

James, If you strike out elsewhere on the schematic, try the Folks at NCTM. They have an N&W Geep that they run and I'd bet they have a print. I'd agree with PC on checking the headlight resistor first -- most headlight troubles we've fixed is usually a bad resistor or a wire connection at the resistor.

ETA

I have a schematic for the B&O 6400 series GP-9, but may not have the latest revisions. It's about 42 x 70 inches that could be scanned to a CD, but don't know what the cost would be. Message me if interested in a copy and I'll check the cost.

Fred

etalcos replied,

"...There should not be any ground(s) of any kind on the locomotive -- ever."

Which I totally agree with ETA.

Am I tangling up what a word or circuit diagram symbol means, or represents?

Clearly, the recent post related to a 1940s era 45 ton locomotive wiring diagram shows the classic
ground, or "chassis" connection point all over the drawing. Including reference to
"TEMP MOTOR UNITS (WITH GROUNDED CASES)"

I guess I'm treading into territory I'm going to learn more about if this thread has more to bleed.

I'm not ashamed of leaning something. It's actually refreshing.
~said as if I was your neighbor looking over the fence~~~ Honestly!

As for scanning a huge 42" X 70" electrical drawing... one can always prop it up in a parallel and concentric position (with good lighting), to a digital camera mounted in relation to it and... render a pretty good image at no cost other than the time devoted in doing the task.

Anyway... Really enjoy this forum... and here's to success in figuring out what's not working on that GP9!

If I was in your neighborhood, I'd climb onto the piece of equipment and help you find the fault(s) : )

John

I have purchased 1st generation wiring schematics and wire running lists from EMD. They will need the order number.

To try and get close enough to read the schematic and stitch this all together would be time consuming and marginally successful at best. I tried this for the project it was purchased for and ended up going and having a roll print made of it.

Fred

Thank you all for your responses.

In an event that some of you will understand, our Chief Mechanic suddenly remembered the other set of wiring diagram, stashed in the short hood. It is the exact diagram that I was hoping for. I poured over it during our chartered excursion today, finding most of the information that I was looking for, regarding the terminal block.

Checking the Negative side of the system sounds plausible, especially since what I believe is the cable tray is down on the floor of the engine room, and likely full of water. I'll open up that tray next week, and if it's wires in there, inspect them for corrosion. If no obvious problems are found there, then I'll inspect the Headlight Resistor.

While looking over the diagram, I realized that EMD evidently intended on the 'Front' and 'Rear' of the locomotive to change, depending on the control stand. As far as the lighting goes, that is. So for the No. 1 stand, the Front is the short hood, while for the No. 2 stand, the Front is the long hood. I have a naval submarine in my background, in which the front was the front, and rear was the rear, no matter which way you were facing. Perhaps it's a good thing that Fairbanks-Morse didn't built a dual control stand unit.

Thanks again,

James

"I have a naval submarine in my background, in which the front was the front, and rear was the rear, no matter which way you were facing."

I knew there was a reason for that "F" stenciled on the bow of the 688-Class boats we built at E-B back in the 70s!

Howard P. (aka 68015)
Second Shift
Main Yard, Groton, Conn.

I have seen 3 arrangements.

- everything isolated. I can't name any specific examples but would definitely be on a diesel.

- Battery circuits grounded to chassis - traction circuits isolated. Typical small diesels e.g. 45-ton, which are designed by nature to be serviced by truck mechanics.

- Traction circuits grounded to chassis, battery circuits isolated. This applies to electrics, which have traction ground via the rails. E.g. Westinghouse HB (hand, battery) or AB (automatic, battery). The purpose of the isolation is to prevent the traction circuits from "seeking ground" via the trainlined MU controls, in the case where a motor's wheels get on rusty rail, ice, etc.

- yes, there is a fourth case: EMU cars with no battery whose controls are powered off the trolley, e.g. Westinghouse HL (hand, line). Obviously they cannot be isolated, and both traction and control ground to the rails/chassis. To solve the "seeking ground" problem, they don't trainline control ground... so a car which loses traction ground also loses control ground and its line contactors drop out.



As much light as possible, as uniform as possible, no shadows. The sun is by far the brightest light you'll get, and a cloudy day gives diffuse light. Your Photoshop guy will thank you later. The reason to Photoshop it is reduce the file size dramatically as compared to a color photo.