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Diesel Service Updates

Diesel Service Report – June 20, 2020

By June 20, 2020January 26th, 2022No Comments

Diesel Service Report, June 20th, 2020

Fairbanks Morse H12-44M, AT&SF 560

Our investigation for the restoring the locomotive continues. Last week we identified that all 12 fuel injection pumps were stuck so that they would not supply fuel to the combustion chambers of the six cylinder 12 piston dual opposed piston Diesel engine. Richard Berk and John Salvini removed one fuel pump and found that the fuel rack would not move. The rack position in the fuel pump is what determines how much fuel is feed to the cylinders during every revolution of the Diesel engine.

The stuck fuel pump plunger that gets depressed by a tappet plunger, was the cause of the rack not moving. The removed pump was soaked in kerosene for 4 days but that made no difference. The main plunger was still stuck in its full downward position.

Contact was made with a local Fuel Injection Equipment company and they have agreed to take the first pump apart, clean it and check to ensure there are no damaged parts inside. They will then reassemble, adjust, and test it. They will also pressure test, or pop, the fuel nozzle which is the device that sprays Diesel fuel into the combustion chamber.

Once the company lets us know what was wrong with the first pump, and the cost to overhaul, we will decide if we will send them the remaining 11 pumps and nozzles. We have a second vendor that has already given us a quote for this work.

This week John removed two more fuel pumps and nozzles, leaving nine more to remove. They all appear to have failed in the same way. Sitting unused for over 25 years, left gum deposits in the fuel pump and when the camshaft forced the tappet to push the pump plunger down, the pump plunger became stuck and just stayed there. After the remaining nine are removed, and we receive a price quote for overhaul, we will send the additional 11 pumps and injection nozzles out for repair.

Each pump is serialized and that is critical. They must go back into the exact same location on the engine where they were removed from. If not, then we have a lot more work to do adjusting spacer shims between the pump and the tappet assembly.

To reinstall the pumps, it is necessary to roll the Diesel crankshaft over slowly to properly set the camshaft lobes so the fuel pumps can be reinstalled. To roll the engine over, a barring tool is supposed to be used. We don’t have one of those tools nor do any of a number of other museums that have Fairbanks Morse locomotives.

John located a line drawing of the barring tool in a parts manual. Part of the tool was still bolted to the engine block but the handle and ratcheting dog were missing. Carl Pickus used the picture and the dimensions from the plate on the locomotive and fabricated a new tool for us. Now we can rotate the engine without starting it. This is Carl’s invention (right). And it works.

John tested the high voltage circuits in the locomotive. That is done with an ohmmeter first to see if there are any obvious electrical shorts in the system. Once that is done, a device called a “Megger” is used. It performs the same test but uses a test voltage of around 500 volts instead of 9 volts. If there is any current leakage at that voltage, the Megger will indicate it. The good news is that all the high voltage circuits tested excellent. Typically, we think of a reading of 1 Million ohms as being an acceptable circuit. Johns readings came out well above that. That was exceptionally good news and is one more risk area most probably eliminated.

USAF 1601, USAF 80 Ton GE Switcher

Three weeks ago, negotiations were started for the purchase of a complete truck assembly that was removed from another 80 Ton GE Switcher that was scrapped in Kansas City. Two weeks ago, the purchase was made thanks to very generous donations from members.

The new truck arrived last Monday.

Both trucks under our locomotive have one failed traction motor. We should be able to swap the Combos, which are the wheels, gear case, and traction motor, from the new truck into the old trucks, or if the gear ratios are different, we will swap just the traction motors. The swapping of combos is straight forward. If the gear ratios are different and we can only swap traction motors, then the job becomes more difficult but still achievable.

The fist thing that had to be done was to remove the two existing trucks from under the locomotive. Before that could be done, Fred Nicas and Carl crawled under the locomotive and disconnected the traction motor wiring. That was exceedingly difficult to do without being over a pit. When the new motors are ready to be wired up, we will be sure to do that work over an inspection pit.

Frank Kunsaitis removed the side bearings and safety clip devices that keep the trucks from separating from the locomotive if the locomotive were to roll onto its side during an accident. Carl then disconnected the hand brake chain and the air-brake hoses.

We knew that pulling the trucks out from under the locomotive was going to require removing the side steps on one end of the locomotive. Carl and Doug removed those steps during the week.

After everything was disconnected, it was time to jack up the locomotive body. The problem was that our tall 75 ton air operated jacks were too tall to go under the jacking pad area under the rail of the locomotive. Carl used a large hydraulic jack to first raise the locomotive high enough to get the air jacks properly located.

After the air jacks were in place, Fred coordinated the jacking, slowly raising one end at a time, 4” each time and making sure that the locomotive body stayed level from side to side.

Finally, the locomotive body was high enough so that both trucks could be pulled out from under one end of the locomotive. The two trucks were chained together before the pulling started. That way no one had to go under the locomotive while it was on jacks and the trucks were moving under it.

This (right) shows the first truck coming out from under the locomotive and the other one is right behind it being pulled by a chain. Carl used his Deck Crane to do the pulling.

After both trucks were pulled out from under the locomotive, Fred led the effort to build substantial wooden platforms under each of the two bolster posts. To avoid leaving the locomotive high in the air, Fred had the crew, Carl, Frank, and Doug Newberry, lower the jacks down to the point where the locomotive body was raised only about 12” above its normal position.

After the blocking was in palace, the jacks were lowered again so that the locomotive rested partially on the wooden cribbing and partially on the four 75-ton jacks. It is very stable and will remain jacked and blocked for some time as we investigate how to swap either truck combos or traction motors.

The new truck obviously isn’t new. It came out of a locomotive that was being scrapped because a failure, someplace in the locomotive, was too expensive to repair. When locomotives are scrapped out, it is common practice for parts dealers to sell portions of the scrapped locomotive as RTO’s, which means Running Take Outs. That means the parts were supposedly working when the locomotive was scrapped so it is assumed that they are still operational.

When we inspected the newly arrived truck, we found the wheels to be in excellent shape. We still need to prove the gear ratios are what we need but that is secondary.

Primarily, we needed the two traction motors. And buying the whole truck was less expensive than buying just the two traction motors.

When we inspected the traction motors, we noticed that the mounting supports for the “nose” of the motors were in pretty rough shape. It’s not a problem because we will be using those parts for spares. But it’s interesting to think about the scrapped locomotive when it was running and how the nose of the motor must have bounced up and down every time the locomotive was used.

This (left) shows one of the missing bolts from the motor nose snubber mechanism. It didn’t pose a safety problem but raises questions about how little, or no, maintenance was performed on the engine. It’s not uncommon for old locomotives to be used, with very little maintenance, until they fail and then get cut up for scrap.

OERM 1956 & 1975

1975 was operated during the week and the brass bearing in the journal box that had a lot of water in it, overheated again. After a day of operation, the brass was too hot to touch but not hot enough to cause the oil to smoke. In addition, two journal boxes on 1956 were found to have water in them. This week, Frank will get the water out of those boxes, change out the journal pads and pour fresh oil in them. The bearings in 1956 were not getting hot so there is very little chance that the bearings were damaged. However, the bearing in 1975 may need to be refitted if it continues to overheat.


USAF 7441

Tom Platten continued to work on the locomotive. His latest project has been to locate thick Naugahyde fabric for the arm rests and seats. He has fabricated new arm rest frames but will need to upholster them. He believes he has finally found a source for the material. He is also investigating paneling certain areas in the cab to cover over the original tarred area that could not be cleaned.

Dave Althaus

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