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My column for this month will address cold weather protection for locomotives. Also to be featured will be more of your questions, along with an addition to a portion in last month's presentation.
The present edition of UP's air brake rulebook contains provisions which focus on what steps are to be performed whenever cold weather conditions are present. These may be found under Rule 31.13.4B (Prevent Engine Cooling System From Freezing).
As those of us who are longtime railroaders are aware, rules changes and amendments by way of General Orders issuance are a regular occurrence in this profession. Rule 31.13.4B has received some cosmetics changes through the General Orders format.
One of the items the document focuses on concerns steps for proper notification of the train dispatcher regarding dead-in-consist locomotives. It also includes the situation of remotely controlled consists on Distributed Power trains, along with what actions to be taken in attempts to restart the dead unit.
Additionally, the contents had a set of instructions which were in effect for only the 1996-1997 winter time frame. These were directions for performing a technique called Locomotive Reverse Shutdown; the intended purposes for this are:
To wrap up this outline: Railroad mechanical departments, along with the locomotive manufacturers and vendors, also have available control systems and other appliances which may be applied new from the factory or as a retrofit which have proven their value in assisting with cold weather protection of locomotives.
As various times, I have focused on them in previous issues of CROSSROADS. So by chance if you still have any of them in you possession, those will contain how they perform in more detail.
Not necessarily does a cold weather operating hinderance mean that the cause was from a diesel engine shutdown. Here is a tale about a cold weather situation which occurred in the Powder River Basin region to a very famous new technology model of locomotive: The SD70MAC units of the Burlington Northern Santa Fe railroad.
While working as DPU field trainer on job CCDSA-02 on March 6, 1996, I found on the lead locomotive a set of track bulletins issued by the BNSF Orin Line train dispatcher; among its contents was a Form D track bulletin which most definitely captured my attention. In its entirety was the following information:
"In extreme cold weather conditions, EMD type SD70MAC locomotives are subject to decreased tractive effort.
This decrease results in a maximum tractive effort of 82,000-85,000 lbs of tractive effort, regardless of throttle position (Run 5 limitation).
Should a stall occur as a result of cold weather decreased tractive effort as evidenced by tractive effort limitation, before attempting a restart, cold weather protection device must be allowed to reset by following procedure:
So what's the story here, and how was a happy ending achieved?
Well...let's begin with a weather report: This situation would surface whenever the outside temperature hit 12 degrees below zero or worse.
What was determined as the cause? An answer in basic language: It was due to cold phase module coolant temperature (The phase modules are the appliances which chop DC into 3 phase AC for use by the traction motors).
An answer in more technical terms:
The cause was traced to a bad software "bug" in the inverter control system. So no one misunderstands...Yes, the protection feature did properly react as
it should have by imposing limitations on load output, horsepower output, and inverter operations in order to prevent the conditions which would cause the inverters to produce more heat than what the phase module cooling fans could dissipate, resulting in the modules burning up.
The correction for this situation was accomplished by doing software modifications to the cold weather protection program. Since these changes were implemented, there haven't been been any more problems with load production to the full 175,000 lbs tractive effort rating of the SD70MAC locomotives under extreme cold weather conditions.
In the outline which dealt with air brake Rule 31.5.6 (Continuous Dynamic Braking), you may recall it addressed in its contents the Dynamic Brake Holding System arrangement.
There is an item which I would like to add for you information benefits; it concerns operations of locomotive consists with the leader being a Burlington Northern unit.
Along with emergency brake applicatins, BN units have their circuitry modified so that Continuous Dynamic Braking will be activated and release the dynamics if the BCPS detects the 20 lbs or more pressure in normal train handling situations (much like IPS does on locomotives with Extended Range Dynamic Brakes).
2. Q. On a trailing unit, if you find the PCS Open light illuminated, how will this affect the loading capabilities of that locomotive?
A. It shouldn't have any. First-The PCS knockdown occurs from the the
lead unit of the consist, as it has the automatic brake valve cut in.
Second-Locomotive employ a modification which allows for full output to be produced when coupled in multiple unit consists from the lead unit, even though the PCS Open light is on on the trailing unit.
3. Q. With AC Traction locomotives: Is the inverter per truck format better than the inverter per axle type (or vice versa)?
A. This depends upon your personal preference. GM and GE went the routes they did after conducting extensive research on inverter control system formats in the areas of design and construction.
Yes, each version has their own advantages in the area of performance, but in the end, the capability of overall performance best determines the results.
I have received a number of inquiries about the new two-way H-O-T-D box manufactured by Rockwell Electronics; their name for it is the Gemini.
Here is some background about its development: Rockwell received assistamce from UP personnel in the Operating Practices group (This included some of the MOP's) and Locomotive Engineering & Quality with this project. Last summer, they were field tested on the UP in these corridors:
There was another appearance of an SD90/43MAC locomotive on the OKT Subdivision; it happened on December 15, 1997. At Wichita, Kansas, train GSHUHO-13 (Grain Shuttle-Hutchinson, Kansas to Houston, Texas) came onto the OKT with lead unit UP 8067 (SD90/43MAC) and SP 244 (C44AC) pulling 99-0-12,859 tons in the conventional configuration. UP 9112 (C40-8) was added to the train at Chickasha, Oklahoma for journey into Fort Worth.
There have been times I have been asked why I get to be so tenacious with my inquiries about conditions and circumstances. It is because I am a person who wants THE answer to my questions and not just an answer. In the workplace, it will make the difference between 100% compliance (that's from having the answer) versus getting into problems (which can result from getting just an answer).
In everyday living, if you are searching for The answer and not just an answer, turn to Jesus Christ (See John 14:6), for He Will always be there to provide you with The answer.