Most are aware the DL&W painted F3's were the substitute power more many of the longer Steamtown excursions in 2011. It the later part of the year #664 slowly developed a worsening electrical ground which repeatedly kicked out the ground relay. Several problems related to bad control wiring and broken insulation were identified and corrected in September. With the issue seemingly corrected the pair of F3's was out again for the Scranton to East Stroudsburg trip on 10-15-11.
They made it one direction but the ground issue returned and other unexplained events occurred that prevented the pair from being able to return to Scranton. There were some initial reports of main generator failure on one of the F3's but that was proven to be totally false. But have been started and run on their own short distances since that trip and all major systems check out OK.
A meeting has been held with Steamtown about Winter work and they have agreed to keep one track open in the roundhouse for the F units. New Exane wire has been purchased and ARHS volunteers and others will replace several thousand feet of control wire over the winter. Fortunately we have recently found the correct EMD wiring diagram applicable for these two locomotives which will make the rewiring job much easier.
With good progress over the winter the oldest set of operating EMD F-units will operate again on Steamtown trains in 2012.

Well they sound as if they have their work cut out for them this winter. Rewiring any locomotive is a major undertaking, but worth it if it is to be a reliable runner.

The Exane wiring is a good decision that will pay dividends in additional safety for personnel and security for the locomotives. These locomotives have high voltage circuits to the transition relays running through the cabinet and any insulation failures that generate a short circuit can ruin your day and your locomotive too.

PC

Preston makes a good point about main generator voltage being present in the transition and also the wheel slip detection circuitry in the cabinet.

Rewire is without a doubt the way to go, but you also need to qualify all the components on the high voltage side. Even though the component may function properly it in itself may have enough leakage to cause ground relay.

I've been burnt a few times when a unit comes in reported with ground relay. It goes across the fuel pad and then mysteriously heal itself. Then gets dispatched on an outbound train where it fails again. When you talk to the pad foreman it "Pulled 1400 amps right through the brakes".

Ground relay is a function of voltage leakage and at stall there is virtually no voltage. Voltage only picks up when the traction motors start to rotate.

Track testing will only get you so far. The most effective way to correctly track down the source of ground relay beyond something overtly obvious is with a megger or hi-pot...and the megger will only get you so far. You can also cause some serious damage to the equipment and yourself with both.

Even with the proper test equipment some grounds just require a lot of patience, good troubleshooting practice, and a certain amount of luck.

EBL

Fortunately, the ARHS has access to both a megger and Hi-pot at Steamtown and some experienced advisors. I completely concur with Eric's statements regarding troubleshooting grounds. In my opinion it is a good practice to routinely megger the high voltage circuits and keep records, watching for a circuit to lose insulation value, and be proactive in repairing said circuit before it becomes a problem. This is more necessary for the older equipment than stuff that has been built in the last 25 years. Remember to isolate any circuit with solid state electronics before using either a megger or hi-pot, or you may see the infamous magic smoke rising out of those components. I have seen a lot of restorations were the wrong insulation value wire was used on the ammeter, transition, shunt field and wheel slip circuits, remember these are all high voltage circuits and typically require 2000 volt insulation.

Mike Tillger

So this begs the question for those who have done it, what is the approach you take to a project like this? Obviously the print is essential, but it sure seems like a job that could be a mess if not handled correctly. Is it a multi person job? Anybody have a prefered technique?

ETA

I will offer an opinion on this based on my own experience, hopefully Mike and Eric or others can add their own perspective. These are just offered as suggestions in an attempt to be helpful. Others may have different opinions.

A partial rewire is often quite challenging and time consuming because you have to work around what is already in the cabinet and cause the least possible disturbance. Assuming you are going after control wiring and not replacing the heavy cabling in transmission, battery charging, and starting circuits, I would suggest:

Make sure you have the proper schematic and also have the correct type of wiring for each circuit you are replacing, as Mike noted earlier. Use the very best wiring and supplies you can get for the application, it will pay dividends in the long term. If you can obtain a copy of the factory wire running list (names all wires, specifies their sizes, origin, and termination) that is also very helpful.

Photograph the old installation from as many angles as possible so you have a record of which directions the builder routed the wires from each device.

Get a good primer on electrical safety and get all the people together who are likely to work on the project and review the safety issues with them before working on anything on the locomotive.

Make sure everything is electrically dead and the batteries are disconnected, both positive and negative sides, before doing any wire removal. If you are going to be dealing with any circuits that have capacitors, make sure they are discharged.

Clean out the wiring being replaced as carefully as possible, keep all screw fastenings on older electrical gear with the specific connection they were originally installed on, do not throw them all in a box, keep them on the devices on the correct connection.

Clean up the interior of the cabinet while it is at minimum installed wiring. Add any wire straps that you think may be helpful with the rewiring.

One person can do the new wiring installation but it is likely to be a long and challenging job. The chances of making an error are usually reduced when you have a team work on the project and check each others work. Personally I think three people working as a team is ideal, two electricians (one working upper cabinet and one lower, change locations occasionally) and a third person to hand in wire and tools, check the schematic, and act as quality control and auditor. This third person should mark off all the replaced wires on the schematic or wire running list as they are completed. This is a good job for an older person who has electrical experience, he sometimes can catch problems that may not be evident to the guys running the wires.

Run the new wires loosely to start with, through tie wraps looped from hanging straps. You can tighten up the wire bundles as connections are completed.

Try to roughly follow the direction and routing that the locomotive builder used. They often had perfectly good reasons for routing wires the way they did so why try to do anything different if you do not have to.

Ring out the circuits with a battery pack and a doorbell, or check them visually with a trouble light and battery pack to insure continuity to the connectors on each device. It is a good idea to do this circuit by circuit as you complete them. Don't count on meters for checking continuity, they may not put enough load on older circuits and devices.

Clearly label all wires with wire tags, which are sold in packs.

If you can do so, try to work on one circuit group off of one breaker at a time, getting that set of circuits as complete as possible before progressing to another group. This makes it a bit easier to keep track of your work.

Check for grounds as each circuit group is completed.

When you go to energize circuits after working on them, only close one breaker at a time, watch and sniff the air for a while after closing each breaker to make sure nothing is getting hot. You may prefer to use a jumpered power source for initial checking rather than the locomotive batteries, that is often quicker and easier to disconnect if anything goes wrong.

Others may want to add to the list.

PC

All,

Thanks for all the advice and suggestions. Duly noted.

A good portion of the control wiring was redone with exane wiring in the 1990's when the components from the CF7 were installed and that still is in good condition. The main target is the main conduit wiring from the front terminal board (in the cab) to rear terminal board over the rear door.

Rich

Rich-

EMD has a 27 conductor Exane MU cable available, with all the numbers marked on it and with the correct wire gauges for each circuit; i.e. 4 (battery -) is a larger conductor than 2 (alarm). Using that to get to the rear MU receptacle, with a few extra loose wires alongside it in the conduit for markers and lighting, could save you a lot of time. LIRR used it in the cab cars and under the MU cars converted to push pulls; saw some last week, in fact-

EDM

I would like to offer one more suggestion just for general situations where you are troubleshooting one circuit. If you have to replace just one wire on a locomotive where the wires have been in place for a long time it is usually much better to do it as an overlay on the cable bundle than to try to extract a bad wire from the bundle. I realize it looks sloppy to have a brand new wire highly visible on top of everything else, but prying apart a cable bundle can damage the insulation on other wires and lead to the need for more repairs in a short time. This is even true in locomotives that were originally done or rewired with Exane wire. Exane has been around since the early 1970s and has proven extremely durable and reliable but it is not bulletproof.

If you are using crimped eye or spade fittings, be very careful about the quality of what you are applying. There are numerous cheap electrical fittings now sold in electrical supply and electronic chain stores that are poor quality or improper materials for locomotive application, and they may not hold the crimp or may not have enough metal cross section to carry the current the wire is rated for. I suspect at some point the poor quality of some types of imported fastenings, both electrical and mechanical, is going to become a high visibility problem with investigations and recommendations for changeouts, but that has not arrived yet. Right now people seem happy to pay the lower price and then wonder why things failed.

PC

I note that T&B and AMP would be bullet-proof choices for crimped terminals-still made in the USA and 'approved' by the locomotive builders. I've purchased what was supposed to be an American brand name terminal from an electrical jobber-only to notice later that they came from the Far East. Right in the trash they went...

Another note concerns the orientation of the crimping tool on the barrel of the terminal. The anvil of the tool should be positioned to make the crimp on the part of the barrel that is NOT seamed. When done this way, it should be impossible to separate the wire from the terminal.

Final note-on crimping tools. In their technical literature, the terminal manufacturer will reference a correct tool or tool(s) for the terminal in question. These are not inexpensive-but one will obtain consistently made-to-spec crimps over the span of the job versus the homeowner grade tools that most folks are familiar with. If one has access to the EMD tool catalog, these tools are called out within.

DPK

Following up on Preston's post we generally use just one electrician on our control rewires. We assign a helper as needed to assist on wire pulls etc. The process is pretty straightforward.

1. Remove all components and set aside for qualification.

2. Remove all control wiring.

3. Scrap all terminal boards, circuit breakers, and light bulb sockets.

4. Clean all cabinets, prime and paint, and blow out all conduit runs. Repair conduit as
needed to include strain relief and anti-chafe bushings as required.

5. Apply new or re-qualified components.

6. Pull wire runs per running list to appropriate zones and include spares.

7. Make terminations as per schematic and running list.

8. Mark up schematic and running list for any as built modifications.

The best thing we have done so far to increase productivity and take some of the misery out of the rewires has been to purchase a Brady industrial label printer. They make label material that is resistant to oil and dirt. Another thing we do is set the rewire unit aside and allow the electrician to work on it in relative peace and quite.

On the reliability and cost side the best thing we have done has been to abandon the EMD EI transition system and go to the Bach-Simpson digital transition control. We can purchase the Bach-Simpson component for just about the same price as getting the EI transition relays rebuilt. This also lets us get rid of all the transition resistors and associated wiring. Its also easy to do a transition check at every 92 and does not require putting the locomotive on a load box to calibrate as it is speed actuated. Second to the transition mod is the installation of electronic cooling fan and shutter control.

I agree with Preston about running a new wire or picking up a spare as opposed to splicing in anything but that should be reserved for wire failure, not interlock or other component failure. More often then not I've seen the jumper wire runs rigged up just to get the unit loading and the locker quickly becomes a spaghetti factory as other components fail. It's usually easier to find one problem then three at the same time.

We do not allow butt splices in any rewire job or to be used in any partial job inside of a conduit. Butt splices are OK in a junction box for example where the fuel cutoff or axle alternator cords enter but are generally the first place I look when a unit won't stay running or is reported with defective speedo.

I would not use the 27 conductor cable inside a conduit run. Its easier to pull the correct amount of conductors and spares. The MU pot-heads and junction boxes are a big source of control grounds. The wire runs generally do not run straight from end to end instead they go to terminal boards.

For Stay-Cons AMP or T&B only. Make sure the insulation is not stripped too far. The insulation has to fit into the end of the Stay-Con properly and be crimped by the jacket of the connector as part of the process to properly support the wire.

An SW1500 with old neoprene insulation will yield two 45 gallon trash cans full of wire and about fifty pounds of dirt.

EBL

EDM, EBL, and DPK, thanks for all the additional information which I am sure will be appreciated by the participants in the discussion.

As some of us have discussed off-RYPN several times, I think the issue of improperly engineered foreign made fastenings (both electrical and mechanical) is a smoldering problem lurking in the background, not fully appreciated yet by our regulators and safety people. I read an article recently that it is becoming a very big issue now with the military. It should become a bigger issue with US transportation industry as well, provided they are paying attention.

PC

Eric mentioned the Label maker. Buying one of these Saves hours over the course of a rewire. Don't scrimp on the tape! The quality of the tape proves it value over time. Plus it makes a cleaner looking job.
As mentioned before a good crimp tool is critical! We have found a style that you have to bring the handles all the way together before they release. Makes a good consistant crimp.
A stupid little trick we do is use 2 prints. One gets highlighted and initialed when each circuit is complete. This comes in handy when you can't work on it every day.Or if more than one person is working on it.The other one is a working print.

Even with the proper test equipment some grounds just require a lot of patience, good troubleshooting practice, and a certain amount of luck.

Luck! Got called out one night about a ground relay tripping. Popped open the side doors under the cab and was getting ready to take a look. The train master asked if he could try and move it to get it out of his way. He said it didn't do it every time, I said sure go ahead. I was standing on the ground next to the locomotive. watching and as soon as he pulled the throttle out I saw a red outline of a coat hanger and the bell went off. Sure enough our slob of a crew dropped a coat hanger in the electrical locker!

For Alco and GE (U-series), one needs copies of the 'Physical Wiring Diagram' in order to rewire a control cabinet. For Alco, there are usually two (Control Cabinet Upper and Lower) plus a diagram for the remainder of the loco, usually refered to as 'chassis.' All the wire specs are called out within.

GE has (1) physical wiring diagram for the cabinet when both the lv and hv controls were located within the platform-and at least (2) on the Dash-7's when the lv controls were re-located above the platform.

Another tip is to use high quality tooling (Klein, Greenlee) for cutting and stripping wire. Import tooling will have a hard time cutting through the Exane jacket cleanly without nicking some of the wire stands. One of these manufacturers makes a very nice tool for wire stripping in the smaller guages-the tool is a rachet affair that consistently grips the wire and removes the jacket without nicking any strands.

DPK