In my part of the world- the flat upper plains corn & bean field part-most trains I see are unit trains hauling grain, ethanol or pink rock, or a local with 10-20 cars. Today I was surprised to see a pair of SD70 pumpkins running light through the corn fields. While this is uncommon around here, I presume there are places where light moves are more common?
I’ve seen such moves on the CSX “Chicago Line” through Utica. Sometimes just a couple of locomotives, sometimes 4 or 5.
Either they needed the power where it wasn’t, or a local had all drops and no pickups and was headed home light. I have seen that with military trains here.
Not that uncommon that light engines out of a terminal are out searching for a unit grain train to get started out of an elevator.
Not exactly a light movement, but I encountered six big six-axle units westbound out of Barstow, CA with seven beat up MOW gons in tow. My take - the eastbound grade out of Bakersfield is a lot longer than the grade from Mojave to Tehachapi. East of Barstow is generally downgrade to the Colorado River, then up to the Arizona Divide on a gentler grade than the one over Tehachapi. Hence, each eastbound can shed a unit or two at Barstow, which then have to get to Bakersfield to meet eastbound needs.
If I’m mistaken, I’m open to correction. I’m just an interested observer with no inside source of information.
Chuck
Sometimes one can overthink these things. A lot of times it is just a matter of what power is ready and avaliable at the time - esp. for extra trains like MOW work trains. And if it’s a set of 6-axle road power, then so be it.
And with the railroads continuing to purge 4 axles off their rosters - you will see a lot more 6 axles doing the oddball/extra/local work.
Overthinking this a bit… Downstream from us, the customers are grain elevators and ethanol plants shipping and receiving unit trains. Those are always hauled by big units, 2 on the front and a DPU on the tail. I’d guess that it should be pretty easy to estimate the power needs on trains like that. That’s why I wonder more than I should. If they hauled the empty train to the elevator or ethanol plant, they should still have the units there to haul them out.
CSX would frequently run lite engine moves to reposition power. Eastbound trains usually haul more tonnage than westbounds so power builds up at eastern terminals. Sometimes extra power would be added to westbounds instead of running a lite move. I’ve had up to twelve units on some trains.
Assuming the power is good to turn. Sometimes it isn’t. May be shopped or FRA dead.
Sometimes the next expected load out of the train may not be for a week or two and no need to tie up power that long. Or maybe the train was taken to a storage location until a uptick in business warrants the train being active again.
We seem to run a lot of light power moves to and from elevators and ethanol plants. Sometimes power might stay at the elevator, sometimes it goes back to a terminal. Depends on how short of power they are or if the units need to be fueled.
The ones I don’t understand at times are the long power moves, over a couple of crew districts. Instead of having a train pick up and deliver power they use separate crews for the moves. Maybe there are times when they need power badly and can’t wait, but often it seems those moves could just as easily be done by through trains. Especially hard to understand when the mantra seems to be “cut, cut, cut” expenses.
Jeff
Of the 3 responses by railroaders directly above, I’d guess Jeff’s to probably be the answer in this particular case. I bet it’s kind of hard for a unit train to swing into the pits and top off the tank, so I can see where it would make sense to run the locomotives 50 miles bag up the pike for refueling.
Compared to moving a unit train over the road, a 90 minute ride each way to the fueling rack must seem like a Sunday drive.
You’d think so, but running lite power is a pain in the butt.
How’s that?
We can run light power at the maximum freight train speed, provided speed can be controlled by dynamic braking, which on a couple of subdivisions for me is 70mph.
Except, if you have 12 or less physical axles (2-six axle locomotives) you have to be prepared to stop at crossings with lights and gates until you can see that they have activated and provide protection. (More of a problem on lightly used trackage where a layer of rust might develope on the rail.)
Light power rides rougher than engines pulling cars. I have had a few where we could run 70, not worry about crossings but ran around 50 just because the ride was so bad. And those were newer engines. Some older/worn engines can ride just as bad at the slower speeds.
Not to mention on light power you will probably be doing a lot more throttle/dynamic brake manipulations to maintain speed. On a nice long heavy train, in some places, you might put the throttle in notch 8 and leave it there for quite a while. Just blow the whistle now and then.
Jeff
Interesting that light trains ride rougher. As far as being harder to maintain the correct speed, isn’t that what the cruise control is for? [:P]
Go Murphy! [au]
On a locomotive, that’s for really low speed application (glorified rheostat).
Hey Murphy,
If you really want a locomotive Ed Blysard’s grand daughter may have a used one for sale. [;)]
On locomotives that is called Pacesetter, and it only works at 10 MPH or less.
As for running light engines, CN restricts 1 unit by itself to 30 MPH and 2 units or 1 unit and 1 car to 50 MPH, with 3 pieces of equipment you can do track speed.
And in my experience the rough riding is not caused so much by the lack of cars, but the lack of power being transmitted at the wheel/rail interface. With the units in low throttle, low dynamic braking or idle you will get a very rough ride, even if you are pulling a train. With light engines you don’t need to apply those heavy forces so they ride rough all the time as a result.
On my territory there are a couple crossovers that are renowned for their rough track, no matter what Engineering does to try and fix it. To smooth out the ride everyone tries to approach them going less than track speed, and then throttle up so you are pulling with full power as you go through them, and it does noticeably smooth out the ride.
GE’s Trip Optimizer is supposed to do that.