Rebirth of the 3189

The 3189 was condemned to death because of a "grounded main generator". Locomotive electrical systems are unlike those in cars because of the high voltage generated for traction. In an automobile, one side of the battery is connected to the chassis which means that the chassis provides one wire for every circuit in the car. The wire connected thus is called the "ground" and is usually the negative side of the battery. Locomotives don't work that way. Okay, a typical industrial locomotive does but that is another story. In big locomotives, both sides of the electrical system are isolated from the chassis. This is to prevent a shock hazard to employees and also to keep goofy things from happening in the MU circuits. When a high voltage circuit develops a ground, one side of the main generator output becomes connected to the chassis. There is a relay, oddly called the "ground relay", which is connected between the chassis and a neutral point in the generator wiring. When a ground occurs, electricity can flow through the ground relay coil, energizing the relay and killing the main generator excitation and throttle control circuits. The problem with the 3189 was not a grounded main generator but rather a grounded positive start cable inside the electrical cabinet. This cable is connected directly to the main generator start winding and thus was able to cause the ground relay to trip. Unfortunately, there are not many photos of the re-wiring process as much of it took place inside the cabinets and under the floor. Luckily, LMC received a GP9 for scrap that had not been through GRIP and thus still had the original spec. traction, alternator, battery and starter cables. They were carefully removed and transplanted into the 3189. The whole electrical problem with the 3189 centered around the type of wire installed during the GRIP program. Twenty years after the fact, the "high tech" cable proved to be, shall we say, deficient in its insulating properties. Of course, this is only my opinion.

These two views are of the engineer's side of the main generator. And yes, that is my knee in the way. There are 6 sets of connections between the generator and the electrical cabinet. The red colored bar in the foreground is the "GP" or positive high voltage buss bar. Next is a tube which carries the connections to the shunt and battery fields and then the curved pipe contains the 2 wires for the alternator excitation. The start positive and generator negative buss bars are beyond the curved pipe, and the 3 connections to the alternator output are in a pipe which is barely visible at the bottom of the photo. This area, called "the pit" is normally covered by a steel plate. The generator also has doors covering the brushes.

The view from the fireman's side shows 2 of the 12 the brush holders. The heat lamp was being used to dry the freshly applied red insulating varnish (Glyptol) on the negative buss bar. The set of large relays in the bottom of the electrical cabinet to the left are the transition relays. There are covers which normally enclose the main generator but they have been removed in order to clean out the gunk under the main generator and re-insulate the buss bars.

It is not unusual for locomotives to trip their ground relay when cranking (starting) is taking place. This happens because any grounded wire in the battery system, and there are miles of wire in there, will be connected to the main generator through the start field during cranking. The 3189 suffered from this malady because of the nasty type of wire that was used during GRIP. I fought low voltage grounds for quite some time and replaced a lot of wire in the process.

In the spring of 1990 and again in 1993, the Oakland Army Base held an open house called "Railroad Heritage Days". Various equipment was brought in by the area railroads and in 1993, the 3189 was a participant. Displaying her old Del Monte number, she was an unexpected sight for the crowds and great fun for us to exhibit. Of course, that's me in the cab, grinning like an idiot. Later in the day, Errol and I are discussing something that will no doubt cost us money. Rod Ciganovich photos.

This photo is a study in apprehension. The first trip out in official service on the OTR was a tense experience for me. That's me, photo left, with switchman Brian Copple listening for any strange noise or cry of help from the engineer. The 3189 stayed in service for nearly a year while I painted and refurbished the ABL 44 while the OTR 97 is was in service on the Alameda Belt Line. Bill Wilson photo, collection of Fred James.

Freshly painted Alameda Belt Line 44 rests alongside the 3189 in these views. At this time, the 44 was in service on the OTR in order to test electrical work I had done and insure that the freshly rebuilt trucks were trouble free. The 44 now rests on ex-S.P. trucks frames acquired from a scrapper in Spokane, Washington. When the Santa Fe rebuilt these GP7's, they only used one brake shoe per wheel, with 72 pound cylinder pressure, which is woefully inadequate for switching service, so clasp brakes were part of my rebuild. The ABL 44 is now the Central California Traction 44 and lives in Stockton. My photos.

A night photo session on the Army base was interesting to arrange for the crew because of the security but arrange it we did. About 10 of us stayed around one Saturday evening and posed the 3189 to our heart's content. I think there were as many M.P.'s around as there were photographers on this occasion. Left photo by Rod Ciganovich, right by Jim Plunkett.

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