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And now, as promised...the originally scheduled feature for last month's issue. The topic: What is the story on the ride qualities of the SD90/43MAC locomotives? Also joining in..some special observations, both railfan and on the job experiences, in the motive power world.
Let's begin with this statement: In fairness, the entire fleet of SD90/43MAC locomotives is not encountering these situations. Although there have been isolated reports of rough rides in Texas, the number of reported cases have been most prevalent in the corridor from North Platte, Nebraska to Council Bluffs, Iowa.
In my own more direct look into this, SD90/43MAC unit No. 8012 was a locomotive which got both favorable and not so favorable stories about its ride performance from individuals who have been aboard it.
If by any chance you were wondering...there have not been any cases of rough ride reports with the SD70MAC, SD80MAC or as yet, the 6000 horsepower SD90MAC locomotives. Although all versions of MAC locomotives are equipped with the radial trucks, the version used on the SD70MAC is different from the type in place for the platform format units.
Due to the use of different engine applications, the SD80MAC is 1 1/2 inches closer to the rails than the SD90/43MAC; the 6000 horsepower SD90MAC is two inches lower.
Operating crews noted that the ride qualities would begin to change whenever track speeds were at or higher than 55 mph. The effects they noticed included: excessive lateral motion, and roughness going over public crossings and switches. It was indicated also that these situations became more prevalent whenever they operated over roadbed with concrete ties (This did have some truth to it, but not to the extent believed).
The U.P.'s LE&Q group in Omaha, GM, and the Siemens Transportation Systems folks have been and still are involved with various studies, along with laboratory and field testing to determine the causes and remedies to these conditions. Some of these items include:
Findings:
The parties discovered a condition known as truck hunting (where the truck
begins to twist back and forth) was taking place, particularly whenever
running over concrete ties. It also became known that the SD90/43MAC's would
incur a lot of horizontal bouncing (In a case I had with unit No. 8094 on a
60 mph auto train: the higher the throttle position, along with the higher
the track speed, the more bouncy the ride).
SO WHAT'S THE LATEST
From the U.P.: The LE&Q group is still hard at work on this issue. Meetings at regularly scheduled times between the U.P. and other involved parties are ongoing, with their goal being to put together a solution and eventually, a plan for making those solutions a retrofit modification, along with a standard feature for new locomotives in future orders.
From G.M.: GM is still conducting ride quality testing at the AAR-TTC in Pueblo (So far, SD90/43MAC units No. 8098 and No. 8070 have been there as the research "guinea pigs"). The TTC personnel can create simulations of U.P.'s track conditions there based upon the instrumented rides data. They are also performing lab testing projects; this involves comparing the SD90/43MAC's and other locomotive models in order to put together prints to do these comparisons. GM personnel are slated to come back onto the U.P. property to conduct more ride quality testing.
From Siemens: Their activities will involve changes in the inverter control system software to calm down the " boogie shake" shuddering effects.
I have received a lot of positive response to the special report about the IDP system troubles with some of the SD90/43MAC locomotives. I would like to say thank you to everyone for your comments, along with thanking the various individuals who who responded to my inquiries which helped to produce that news story. As always, I will continue as best as I can to stay in touch with the latest goings on in the ever changing world of advancing technology.
One area I need to go into furthur is based on this situation which happened to an engineer while his train was on the move; he noticed the inability to "bail off" the automatic brake application. Here is the reason why: The E-Brake system has an integral two-way communications link with the IDP system.
When the contact between the two is broken for over five seconds, the E-Brake system will take the most restrictive position, which is Air Brake Fail. This condition causes a loss of power to the E-Brake system, so with it goes the ability to "bail off" the brake application.
1. Dynamic Braking System: On units No. 8075 and higher, they employ a different wiring arrangement for supplying power to the grid blower motor. The format in use: The motor is permanently hardwired to the back truck (the No. 2 inverter). So if for any reason, the No. 2 inverter gets cutout, these locomotives will not have any operative dynamic braking available.
Units 8000 to 8074 employ a different wiring and software arrangements; under certain conditions if the main source of grid blower power (the back truck) is lost, a message will be logged and the front truck will become the new power source, allowing operative dynamic braking to be retained. If either inverter becomes cutout, the locomotive will still have available 55% of full dynamic braking output.
2. Auxiliary Generator Issue: Currently in place is a modification instruction affecting units No. 8176 and higher addressing the situation of unexpected trip-outs of the Auxiliary generator circuit breaker. The cause for this was determined to be extra heavy load sources being placed against this appliance from operations of the cab heater or air conditioner at high blower speeds.
While this project is ongoing: The actions operating crews need to take is to operate these appliances at low blower speed settings.
3. The New Parking Brake System: Have any of you encountered getting an alarm bell and crew message of the parking brake still being applied, even though you had just performed the release procedure? Explanation: The EM2000 (main locomotive computer) does not have a memory to where it remembers the last status of the system. So in order to "get its attention", press the release button until you get the green LED release light, and the meter shows fully released.
If you still have the alarm bell afterwards, and the F3 soft key doesn't respond, cycle the parking brake circuit breaker.
Conventional Format: In the days when the majority of coal train in my area are operating in DPU configuration, it has become rare to witness seeing these jobs with all the power on the point. Train CBTHS-25 was one of those jobs, featuring an SD90/43MAC trio, units No. 8113, 8007 and 8193 pulling 110 loads, 14517 gross tons into McAlester, Oklahoma on April 29th.
Now this train would also have an extra element to it: I found out that the 8113 had the No. 1 truck (inverter) cutout, so the train had a 2 1/2 MAC consist as its power. So my main question later on to the outbound engineer was: "How did this train handle, particularly when it got to Ray Hill at Denison, Texas?"
Overall, in both power throttle and dynamic braking, he felt they were "just okay." With the dynamic brakes, "I had to use air brakes more times to help them out than usual.
" On Ray Hill, "the train speed got down to 5 mph, but at that point, they went after it."
From other crew members (they had with them a student engineer): The two full MAC trailing units pulled up to 145,000 lbs on the tractive effort meter, while the lead unit, now down to 55% of full power availability, was showing 106,000 lbs of output (The engineer remained in Run 8 throttle all the way up the hill).
There were never any problems with lunging or "boogie shaking", and they never got a wheel slip light.
Summations: (1). Although Ray Hill is a 1% to 1.3% grade, a 2 1/2 MAC unit consist will have a tough time, particularly if the grade percentage is 1.5% or greater. This can also occur if you have half a MAC unit on a DPU train, as another engineer I have spoken with had this to occur (his train was at 3 to 4 mph when he crested this hill).
(2). In a half a MAC condition (55% of full output), the equivalent horsepower output is approximately 2500. However, do keep in mind that the dependent factor in the low speed range is how much tractive effort is available, since now you are in the constant torque mode which doesn't require full horsepower for operation.
DPU Format: As I pointed out in last month's feature, not all of the SD90/43MAC's are "dropping the anchor" when they're in IDP configuration.
Here is one of those success stories: Train 2CBTHS-03, which departed
McAlester on May 7th with 129 loads, 15351 gross tons, with this assigned
arrangement:
His responses: "The train got down to 12 mph, but it hung right in there. The highest the tractive effort meter got to on the lead and remote MAC units was 122, 000 lbs."
This was his maiden voyage on an IDP formatted locomotive; he voiced liking to work with this format better than the stand alone control box version. More drama: On the train's return trip as the 2CHSBT-07, unit 7025 was donated to charity (another train); in its place was SD90/43MAC unit No. 8007. So another IDPU train in Texas goes down into the books.
After last month's edition went to our wonderful Editor-in-Chief, I got my opportunities to visit with the crew aboard train 2CBTHS-05 on April 9th. This was the train which featured BN 9639 (an SD70MAC) as its lead unit into Fort Worth.
The Conductor: The locomotive had a real quiet cab; to verify the horn was working, he opened the cab window for a moment. The locomotive had a great ride, and at no time did it do the "boogie shake." A feature he really liked was the David Clark intercom system applied. On Ray Hill, the train went up perfectly.
The Engineer: His only dislike was with the format the KNORR CCB system used for "bailing off" the automatic brake application. On Ray Hill, the train topped out at 12 mph; the highest readout he got on the tractive effort meter was 106,000 lbs.
What was the surprise? The job it was on was not a unit coal train (the crew told me its symbol: H-LAUFTW 3-30A), a mixed freight. The engineer's colorful response to my comment about seeing this event was "It was slumming for some reason". My reply was "It needed a vacation from its normal routine."
In today's world, things can become fast paced, but are they such that you're too busy for God. If so, then you are too busy. So another catchy statement I saw on a church sign by the tracks going to McAlester offers some wonderful advice: God, teach me to go slow, when my way I don't know."