Mutiple engines


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PATrainman

New Member
I was just curious...(again, I am almost entirely new to this hobby)...but the length of trains topic brought it up in my mind...I assume that in real life, they will put two engines back to back, so that it can pull more, but does the same work in HO scale (or on the model layout scale for that matter)?

Which brings up another question...why do they usually put the engines back to back? Why not front to back as logic would suggest?



Justin
 
PATrainman said:
... Which brings up another question...why do they usually put the engines back to back? Why not front to back as logic would suggest?
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Having 2 locos back-to-back enables the crew to simply relocate to the cab of the other unit at the end of a run, when the train needs to be pointed the opposite direction. Saves the RR company the expense of maintaining turntables, wyes, or reversing loops at such locations. (In fact, a point-to-point coal run on my layout depends on this setup because I don't have the real estate to install a turntable at the 'far' end.)

As to your first question, the laws of physics still apply regardless of scale - two engines will provide more tractive force than only one.
 
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!!! WARNING THREAD HIJACK !!!

What a stupid solution! And I don't mean that negatively. It's just that it is so simple that I never thought of it. I was trying to figure out where I could put a wye but I guess now I don't need one. Maybe I need a RR operating book.

Sorry, here is the thread hijack. Along these lines of locomotive directions, are locomotives assigned certain runs or areas or do they just run all over? I understand that a pair of GP38-2's won't be pulling a unit coal train from WY to TX but are there certain (road numbers) SD series that are assigned to these runs? Are there locos that run Denver to Amarillo only and then turn around with the empties?

Any operating knowledge welcome!

Thanks for asking this PATrainman, I learned something new today!
 
First, two engines will pull more cars than one, assuming that they are reasonably matched for motor characteristics. If not, you'll end up with one hauling or pushing the other, neither one of which is a good thing. As far as back to back operation, I think Ken's answer probably applies to runs where there is no wye and the same loco set will set out and then pick a load. If it's a mainline train, I've seen them with the trailing engines both front and back with the exception of the old UP, which seemed to have only the lead engine facing forward and every other engine facing to the rear.

As far as assigned locomotives go, there were definitely some examples of that. Both the UP and the AT&SF had blocks of F units and GP-20's and 24's that exclusively ran fruit blocks. The UP also had SD-35's and 40's that ran Farmer John trains of pigs to LA and the empties back to Chicago. The Powder River coal trains generally had assigned engines as well, usually GE's. They usually ran round robin style, taking the coal to the dumpers and then hauling the empties back again. I'm sure there were many more examples of hotshot freights that had assigned locomotives or classes of locomotives.
 
That's interesting. I'll have to look into this some more. I've seen rail cars that say "Return empty to XXX". I was always curious if power did the same sort of thing.
 
If I recall, EMD sold A-B-B-A F7s in the late '40s as 6000 horsepower road power (cabs on each end, each unit 1500 hp x 4 = 6000 hp).

Only foresee-able (ugh, spellin') with running locos back-to-back on a layout would be possible direct short on metal shank Kadees mounted on the metal frames of the locos. I haven't had much luck isolating Kadees with plastic/delrin screws, but I body-mount the couplers (build up a plastic mounting pad in the loco body), which insulates the couplers via screwing into plastic, not a metal screw/metal shank/coupler short through the frames. I had a devil of a time with an Athearn SW 1200 SP switcher shorting to a stall (I could roll it through fast and jerky with the flywheels pushing it through, but who wants a race car switcher?) when the Kadee hung down and just tapped the divergent rails on the switch/turnout. I cut off the frame metal mountin pads, glued in a stack of styrene on the body, and mounted the couplers there, no more stalling. Flat end of Athearn F unit makes a nice place for a styrene coupler mounting pad and shortens up the long coupler hangout from the back of the loco, and no problem with the coupler swing interfering on the curve. But if you keep the F7 frame mount on the loco nose, don't run the F7As nose-to nose, or same frame/coupler/frame shorting problem.

Of course, if you run more than one powered loco, you pull more juice.
 
Hmm, as far as I can see no one answered to one of Justin's questions

but does the same work in HO scale (or on the model layout scale for that matter)?
Click to expand...

As far as I learnt from here, if you are running on DC, you need to have similar engines from same brand, so they will have a matching motor, unless you make modifications on the locos to match power,(which I won't reccomend), but if you are running DCC it will be less of a problem, since you will set each loco with the desired speed to match each other.

Anyone correct me if I'm wrong, I don't want to mislead Justin.
 
I've had problems with P2K speeds. I have three GP38-2's and one GP60 that are identical matches on speeds. I had another GP38-2 that ran almost twice as fast as anything else. It was so bad that I sent it back to Walthers and had them replace it with a slower chassis. I've also got another SD60 that is a sprinter also but since my six axle power will be club units on DCC I'm not worried about it.
 
Maxitrains said:
...but if you are running DCC it will be less of a problem, since you will set each loco with the desired speed to match each other...
Click to expand...

DCC is awesome for matching locos. I matched up a non-flywheel F7 to a flywheel F7 perfectly using the different settings in the decoder. Definitely recommended for multiple locos.

Mark
 
Maxitrains said:
Hmm, as far as I can see no one answered to one of Justin's questions
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Maxi,
Re-read the first paragraph of my post. You'll see I answered Justin's question directly. In DC, motor characteristics make it more tricky to consist. With DCC, it's much easier but I still have engines that won't consist well even with DCC, some types of P2K engines being notable examples.
 
Hmmm, I apologise then, I think I misunderstood and thought U were talking about real locos

First, two engines will pull more cars than one, assuming that they are reasonably matched for motor characteristics. If not, you'll end up with one hauling or pushing the other, neither one of which is a good thing
Click to expand...
 
P2K's are geared different, thus the issues. If you spend some time plotting the CV speed settings on each unit (using one you pick as a base) then you should be able to set the CV speed settings all to allow everything to be on a general even base.

Set up a circle track with every other track painted white and black, alternating, then program the unit, and test run it, on say speed step 10. count the number of sections is passes in say 30 seconds, or 15, something like that.

On the next unit do the same, if its too fast or slow then reprogram the speed CV's by a few, then try again.
 
Remember to take note of the default CVs and write them down before you start making the adjustments...;) just in case you need to go back...
 
Regarding assigning locomotives to certain runs, BNSF was basically assigning most of their SD70MACs to coal service. They might not exactly be tied to a specific run, but for those in the Executive scheme, you mainly saw them attached to a string of coal gons....

More locally, NS assigned the SD40-2 in the Maersk scheme to semi-regular service on occasion. It'd stay in one area for a month or so, shuttleling back and forth before going somewhere else.

Kennedy
 
Here is a link to the Rock Island power assignment for 1974. http://faculty.simpson.edu/RITS/www/rits2do1204/RI1974PowerAssignments.htm

I wonder if this was a hard and fast rule or if units occasionally ran outside their division before they made it home.

For example, let's say it's 1975 and a RI mixed freight is leaving Houston for Chicago. Will the same power stay with the train the whole way or will the power be changed out once or twice along the way. Assuming there are no mechanical breakdowns or any other unscheduled event. Also assume that the train isn't scheduled to be broken or humped somewhere. Just a straight through mixed or unit freight.
 
Mac, it's kind of like airliners. Assuming that nothing shows up as a problem, one aircraft will make the flight from New York to Chicago. It's basically the same way with railroads. The consist that leaves Houston would be the same one that arrives at Chicago unless it's on the CSX, when all the engines will go dead within 100 miles of their point of departure. :) Seriously, th only time I've seen consists broken up is if there a mechanical problem with an engine or the run goes through a major engine service facility location. If there's an engine in the consist that's due for overhaul, they'll drop that engine and pick up one of the newly overhauled engines. The old SP used to have a big engine overhaul facility at Sparks, NV and you'd sometimes see a train with 8 or 9 units coming over the hill from California. They didn't really need that many units but 3 or 4 were scheduled to be dropped at Sparks for overhaul.
 
Interesting stuff. The more I learn the more I realize how little I actually know. Thanks for the reply.
 
CSX does the same thing today. Sometimes you'll see a train with about 9 locos on it, with about 7 dead in tow. They're headed for some engine facility for their scheduled inspection. We see this all the time in Central Ohio on trains headed for Willard OH. They have a nice engine facility there to do inspections and the like, but not heavy repairs.

Kennedy
 
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