I was on vacation today, so I decided to go out and do some railfanning when I would normally be at work. As a result I got to see a hauler heading to Roseville. The locomotives were a C44ACCTE (AC4400CW with traction control), C45ACCTE (ES44AC), 2 C44ACCTE, 3 SD40-2, and a SD40T-2. I was by the train when it was stopped and it sounded like all of the locomotives were running. When it started moving, it appeared as though all were isolated except for the first three. Since the ambient temperature will be coming nowhere near freezing, I would think that they would have all of the isolated locomotives dead-in-consist. Any ideas as to why their engines were on?
Perhaps a powered-axle limit on that line?
Interesting. We have seen a lot of 3-4 engines on m-t coal going west. Figured they were just moving power around. They don’t look to be running, but not sure. Does it cost more to have them on line but not helping or dead-in-tow? I am sure we have covered this, but need a refresher course.
Don’t the engines have to be running for the air compressors to run? Any chance they needed the air?
I am a bit confused as to what the term isolated in refference to locomotive consists means?? Does it mean that the locomotives were seperated from the rest of the train by themselves?? OR does it mean that the locomotives aren’t running or in synic (sp) with each other??
If the locomotives were on the train and the train was at idle I would agree with broncoman in that case. Or maybe the train wasn’t to be at idle for all that long.
I do know one thing if this train had all of the power mentioned above on it, it must be one long heavy manifest or a heavy haul, slow speed freight.
The hauler seen by Ericsp may have been pedaling freshly serviced power to outlying jobs and/or picking up power from outlying jobs that need servicing at Roseville.
Each unit is equipped with storage batteries for starting the prime mover (diesel engine). If the storage batteries are weak, outstanding instructions require locomotive engineers to keep the units idling even if they’re not being used.
But an idling unit consumes around 5.5-gals./hour or about $12/hour in fuel at today’s rates. Multiply that figure times how many hundreds of units are idling each hour and that’s an awful amount of money going up the stack.
When you haul a locomotive dead in tow, the train line from the compressor on the dead units are cut out, actualy cut through…you pretty much treat the locomotives as really heavy boxcars!
On line, but isolated, the compressors will help with pumping up the train line, the air brake system runs and is controled through the air hoses, not the MU cable.
Isolating the motors cuts the control stand features out, and dis-connects the alternator from the traction motors.
As Bob pointed out, you often need to keep the batteries charged, and even when iosolated, the alternator will charge them.
Quite a few locomotive now have the auto start system, if the air pressure in the reservoir drops below a set point, or the battery charge begins to drop, the locomotive will start itself, to keep the air up and the batteries charged.
Once the air is back up, and or the battereis charged, they shut down.
Getting a jump start for your locomotive out in the middle of no where is kinda hard…and most folks dont have jumper cables that are long enough anyway!
But I do !
I remember one time, in pre-UP days, a crew was having trouble with one of its two units. After radio conversations with the “power desk” or whatever it was called, they were told to try and make it with one (fat chance, with thw train they had). They asked for a jumper cable to crank the disabled lead unit with battery power from the second unit. They got the wrong kind of jumper cable–an m.u. connector! But I knew then that such things really did exist.
I bet your do!
Our shop has a set, they end having to up jump starting the foreign power all the time.
I remember once on the WC … One of the mechanics made up a really nice new set of cables to put in our new shop truck . They were 100’ long , split into two sections , joined in center with push and twist connectors. The only thing he neglected to do was make sure he didn’t swap red and black ends. I was the one fate chose to use these cables for the first time . I was in the cab of the 711 GP-30 with the engineer (Chong Won) when I made the final connection… Guess what happened ??
PS. Chong watched the rest of the proceeding from the ground…
Randy
Many of the newer GE units have “Smart Start” systems which monitor, among other things, the battery voltagage, cooling water and outside temperature and start up or shut down the unit accordingly if it is isolated (off line). Some roads also have the Smart Start installed on SD40-2, and GP38-2 units, etc.
In the case of the GE units there is a built in limit as to how many times per 24hr period the system is allowed to do a stop/start cycle, due I would guess battery and starter motor wear.
Further some roads have issued instructions to engine crews not to shut down the “Smart” units and let the computer take care of the diesel/elect system needs. Of course the units must be shut down asap if a condition that would damage the locomotive is noted such as a broken high pressure fuel line which is still a too common GE failure problem.
The start/stop system has many names and manufacturers, I’m using “Smart Start” as a general name
Here is some more information about the train. It had 67 cars, 66 were probably empty. Its entire trip was in the Central Valley. I have seen a single SD40-2 and a single SD40T-2 a few times handle a longer train on the same route.
Do the newer GE (or EMDs) have issues with older non computerized units? Could the lead unit have selected not to power up the other units on start-up? Are the GE computers that smart yet?
Wasnt this problem deplicit on the cab ride series when they had to stop the ge a few times? I seemed to recall that. (in reference to the New Mexico amtrak films) Hanker.
You know, now that he mentioned it, I think boomer hit square on…the GEs seem to be on a timer, where as the EMDs seem to be on a start up by demand, or random cycle, as the air or battery need dictates.
Broncoman…the units work on a stand alone basis when parked or isolated…the lead unit cant start or shut off the others.
Not yet, anyway, but give them a few more years!
Printer running. This is good information!
Here’s a question for Ed or Randy or whomever,
Say you have two units, one of which had shut down, and you can’t get the doggone thing started because the batteries have gone kaput. Can you put that one into dynamic braking, pull it with the good one, then use the resulting power from the traction motors to crank up the engine? Kind of like popping the clutch while coasting down a hill in a manual transmission automobile.
Signed,
Curiouser
Not that I can think of.
The power generated from the traction motors is directed to the dynamic resistance grid, not the electrical system…
But Randy has the technopoop on that…I never have seen it even attempted.
I have wonderd if there was a way to direct the current back into the batteries, like a trickle charge, though.
I suppose it could be done . We have some locomotives that have spotter control . This allows the locomotive to be moved using one traction motor and the batteries. I suppose it can be possible to put the current from one motor back into the batterys , the only problem I see is regulating the voltage as at too high of a speed you could damage the batterys from too high of voltage.
Randy