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Discussion Starter #1
Was just wondering,

Does the tractive effort increase when mu-ing?

I tried to MU one time about ten years ago; both units were DC power, one from a boxed set and the other a supplemental, additional unit. (Both Bachman.)

When I did this, they had a nasty tendency of uncoupling from each other. I tried rearranging them and they still came apart. (One appeared to be a bit faster than the other.)

In a DCC layout, if someone were to MU, would there be a "net increase" in tractive effort? Could, theoretically, someone pull more cars or pull more cars up inclines, etc...?

Thanks.

Also, I used to post as "SoCalRailfan," but I forgot my login credentials and email. So, I opened this screen name.
 

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With DCC,with a little tweaking though,you can "speed match" your locomotives by lowering the speed(s) of the consisted locos to match the slower one.

When matched up,every loco will add its power to the consist,definitely.
 

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Yes MU helps greatly, just as it does in the real world. I run most of my stuff DC, guessing your failures were likely related to bad/weak couplers.

I have a stack of modern Kato Gevo and ACe units and they all have similar speeds and pulling power. I generally put the faster one up front so it can stay ahead of the other on declines and respond to pushing a bit better. With a good power supply I've run them 4 at a time pulling around 80 cars up grades without issue. I also have a group of Atlas GP-35's I use in similar setups.
 

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I was forgetting that you are running with a power supply coming from a set.Many of these generally have the power to run one locomotive at its potential pulling strength but do lack the stamina to power a second loco at full potential.In this case,the second loco draws some of the power available for the other one so neither will perform to their specs.Adding extra locos won't help,they'll all slow down and pulling power will not improve.

You can't get more power than what your power supply can deliver to the track.I'd check this first.Then faulty track joiners will create the same problem,just as too small wiring.
 

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Another thing to look at is engine weight. Bachmann set engines are notoriously light and have less pulling power. If you are talking steam prototypes you should look at traction wheels to help with pulling power.
 

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Discussion Starter #6
Another thing to look at is engine weight. Bachmann set engines are notoriously light and have less pulling power. If you are talking steam prototypes you should look at traction wheels to help with pulling power.


Yeah, the boxed set loco was much faster than the one I bought after. The one I bought after, was definitely heavier to the feel, and was a tad slower at any given speed setting.
 

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Discussion Starter #7
I was forgetting that you are running with a power supply coming from a set.Many of these generally have the power to run one locomotive at its potential pulling strength but do lack the stamina to power a second loco at full potential.In this case,the second loco draws some of the power available for the other one so neither will perform to their specs.Adding extra locos won't help,they'll all slow down and pulling power will not improve.

You can't get more power than what your power supply can deliver to the track.I'd check this first.Then faulty track joiners will create the same problem,just as too small wiring.
Interesting. Are you saying that there is a power limit to the trackage that can't be "exceeded"? Or, are you talking about power supplied from the controller?

Whatever the case, what you're saying seems right given the results of that experience.
 

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Discussion Starter #8
One thing I forgot to stress in my top post was that these locos were Bachmann and they were from essentially two different product lines: one was the box set loco which, quite frankly, had rather cheap looking paint/detail (an F7 Diesel) while the one I purchased, was better detailed (From their silver series I believe); a GP-38.
 

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The trackage can't carry more current than the power supply can deliver,however,it can and will carry less if there are current wastes along the way with faulty joiners or wiring.

Bachmann has (or used to have) three product levels...Bachmann (found in sets BTW),Bachmann Plus and Spectrum...with obvious quality differences.

Even with their Spectrum line,their quality control is shaky...they're on a "try before you buy" basis.On the other hand,Bachmann are very good with customer's claims,based on my own experience.
 

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Discussion Starter #10
True about the joiners. I can recall having some difficulty when using their "EZ track" trackage - which I don't use. I've been hesitant when it comes to Bachmann. The one thing they've got going for them is that they provide a good variety of road names as well as a decent variety of both steam and diesel locos.

I think I was thinking of their "Silver Series" rolling stock.
 

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MRC 1370's are excellent power supplies for n scale DC layouts. I use them on my Kato Unitrack layout I have setup. It includes one of their double cross units and I am able to run both loops off a single MRC 1370. I have a long outer main line and a shorter in loop acting as a holding loop for the main line while I run the other train through it. I've run 2 MU consists on it with 5 engines total and they all function the same as using the single Kato supply which comes with their M1/M2 sets. When all 5 locos are on the same loop there is no noticeable speed drop and they transition the double cross without issue. I highly recommend it. It has the screw adapters on the side to easily accommodate whatever type of wiring you wish to use.
 

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Discussion Starter #12
MRC 1370's are excellent power supplies for n scale DC layouts. I use them on my Kato Unitrack layout I have setup. It includes one of their double cross units and I am able to run both loops off a single MRC 1370. I have a long outer main line and a shorter in loop acting as a holding loop for the main line while I run the other train through it. I've run 2 MU consists on it with 5 engines total and they all function the same as using the single Kato supply which comes with their M1/M2 sets. When all 5 locos are on the same loop there is no noticeable speed drop and they transition the double cross without issue. I highly recommend it. It has the screw adapters on the side to easily accommodate whatever type of wiring you wish to use.
I'll have to check that out. I was wondering also how good Kato's power packs are? Seems to me like Kato has pretty good stuff in the trackage department.
 

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I'll have to check that out. I was wondering also how good Kato's power packs are? Seems to me like Kato has pretty good stuff in the trackage department.
I've had very few issues with Kato. I purchased a few of their track packs plus the M1 base with the Gevo unit and mixed freight. I was separated from my main stash while I was job hunting in a different state and was going through withdrawals. I fell in love with the stuff immediately. There is no comparison between it and EZ Track. They even have Unitrack to snap track/flex track adapters.
 

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Both Kato and MRC are known for making a high quality power pack. I have the Kato power pack, it's very nice and high quality. I also own two of the MRC Tech II power packs, the locomotion 2500 model, which is also a nice and high quality product. I do not own any of the other power packs MRC builds, but I have read in many forums that the MRC 1370, and all the Tech II, Tech 4, and the latest Tech 7 models are good products.

The power pack typically included in a train set, is only powerful enough to run a single locomotive, to keep costs down. The power packs available for separate sale are usually of higher quality, and develop more amperage. That's why I can run on average 3-5 HO scale locomotives, from EACH of my MRC Tech II locomotive 2500 power packs. I can run even more N scale locomotives on each of those power packs.

I should also mention, a heavier locomotive typically can pull more freight cars, compared to lighter weight engines. Traction tires also increase pulling power, but of course, decrease the electrical pickup (because traction tires are typically rubber or plastic).

I'll also add that under DC power (which is all I use), it's very helpful when both locomotives are geared to operate at the same speed, for the same voltage. Same is true if I want to run 4 locomotives in a single train. It's a huge help when they operate at the same speed, or as close as possible, to reduce fighting between them. That fighting can break plastic couplers.

With DCC control, it's possible to speed match the locomotives (by adjusting the values in the decoder), to get 2 or more locos to run at about the same speed, so they can operate together in a single train.

And to reduce my typing, I'm going to post something I had written earlier at this forum, for another member who had a similar question. I'll just re-post it below. Even though it was written with HO scale in mind, all the information is relevant for all scales.

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Just like NIMT has suggested, "VA (volt-amps) is important but the quality of the speed control is more important." Too be honest, any power pack will control any locomotive (as long as both are compatible with each other, and both are operating properly). But naturally a higher quality power pack will have more power (amps), and also have smoother speed control.

When I first got into the hobby many years ago, like many kids, I had cheap HO trains my dad bought for me. They were a lot of fun, and I have fond memories to this day. But truth be told, my equipment was not very powerful. They were the toys made in the 1970's, such as Bachmann and AHM with the pancake power. They were all pretty lightweight, had weak motors, and poor electrical pickup. But anyway I had fun. I also had an inexpensive power pack, barely able to power my trains.

Nowadays I have two very nice MRC Tech 2 power packs, and they work great for me. They each put out 16VA, plenty of power for me. They are strong, with a lot of reserve power, and have a very smooth speed control. I can easily control 3 or 4 average (modern) HO scale locomotives, all running together at the same time, without any overheating. The much smaller Tyco transformer I had it the past, will not be able to do that. I remember, because I tried to do that in the past. It would start to overheat, plus each train would go slower, because it was not a powerful power pack. It could not handle the load, I wanted to give it. Either I had to lower the load (only operate one loco at a time), OR get a more powerful power pack.

Some of their packs have even more amperage, like up to 20 or 30VA. They also make a power pack with 60VA, which can be used with N, HO, S, O or G gauge DC powered trains. But you don't need to go crazy, and spend tons of money. Just get something good enough for your needs, that will be cheaper then getting the biggest.

Even if you decide to get a more powerful power pack in the future for your trains, you can keep your existing 5.5VA Model Power pack and use it to power accessories, such as lights. A more powerful transformer will you give more power, to pull more. Each single locomotive will only draw as much energy as it needs to run, and nothing more. If you have a very efficient locomotive, powered with a high quality electric motor, (like a core-less 7 pole motor), it will use very little energy to move. With a more typical locomotive, it will need more energy to get the motor spinning. It has to fight the resistance in the motor and gearing, before it will start to spin. A cheap motor has more resistance to spinning. As long as your transformer has enough power to deal with the load from the train, it will not overheat prematurely. It will not be smooth with a low quality power pack, because cheap power packs have a smaller effective range in their speed control. The dial might only move 90 degrees on a cheap controller, compared to around 300 degrees on a high quality controller. Remember a circle is 360 degrees all the way around. That larger range in degrees, will give you finer control between the zero and 12 volts, that HO trains are designed to operate with. Another nice feature with a higher quality power pack, the the internals inside (such as resistors, capacitors, and the speed controller [rheostat or potentiometer], etc) will be of higher quality to handle more heat before melting down. A higher quality power pack usually has a smoother speed controller, and more reserve power.

Also be aware, that modern power packs have more electronics inside, compared to many years ago, to make trains run smoother.

A more efficient motor draws less amps and wattage, compared to a lower quality motor. But the motor (any motor) will only draw, what it actually needs to operate, and nothing more. A very modern and efficient motor might only draw one tenth of an amp, to operate at a certain speed; while an older and less efficient electric motor might need a full amp, to run at the same speed. The power pack will deliver the needed power (such as 1 amps) to that motor -- but only what the locomotive is actually drawing from the power pack.

Let's say for instance, your power pack was designed to deliver 2 full amps (without overheating). If your locomotive needs one amp to run, then you can run two identical locomotives, on that particular power pack. If instead your locomotive only needs half an amp to operate, then you can run 4 identical locomotives together, off that single power pack.

Any power supply cannot deliver any more than it's VA rating (combined volts x amperage), otherwise it will overheat and die. Also as the amps go up, volts come down and vice versa. I hope you understand my explanation. Confusing yeah!!

Anyway you don't need to worry about all that mumble jumble, to run trains. Just do whatever you like, and enjoy the hobby. I just buy whatever locomotives I like, if it catches my eye. And even just an average middle grade power pack, is good enough for my needs.
 

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Both Kato and MRC are known for making a high quality power pack. I have the Kato power pack, it's very nice and high quality. I also own two of the MRC Tech II power packs, the locomotion 2500 model, which is also a nice and high quality product. I do not own any of the other power packs MRC builds, but I have read in many forums that the MRC 1370, and all the Tech II, Tech 4, and the latest Tech 7 models are good products.

.......

Anyway you don't need to worry about all that mumble jumble, to run trains. Just do whatever you like, and enjoy the hobby. I just buy whatever locomotives I like, if it catches my eye. And even just an average middle grade power pack, is good enough for my needs.
Excellent write up! Well worth the read! :smilie_daumenpos:
 

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I am still in the stone ages running DC only. I run MU on a fairly regular basis. Most of my locomotives are Atlas that I bought ages ago when they came out with their Alcos. These are fantastic locomotives and all run at the same speeds (I have 9 of them). I also have a number of old Athearn locomotives that have been repowered with quality can motors which I can use with the Atlas. There is a slight speed difference between the Atlas and Athearn locomotives. I just put the locomotive that runs slightly faster as the first locomotive. The train below is pulling a grade out of hidden staging tracks.



Take your locomotives and put them on a different part of your layout and let them both run at the same time. Put the faster locomotive in front. If there is a really big difference in the speed of the two locomotives, MU servce may not be good because the faster locomotive could be spinning its wheels trying to pull the slower locomotive.
 

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Discussion Starter #19
I've had very few issues with Kato. I purchased a few of their track packs plus the M1 base with the Gevo unit and mixed freight. I was separated from my main stash while I was job hunting in a different state and was going through withdrawals. I fell in love with the stuff immediately. There is no comparison between it and EZ Track. They even have Unitrack to snap track/flex track adapters.
That makes it all worth it, right there! :D
 

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Discussion Starter #20
Howard1975:

No, your explanation isn't confusing at all; rather, it's HIGHLY informative and confirms some of the issues that I thought I was encountering but was too embarrassed to ask the train folks around where I live!

I have spent a lot of time pondering the use/application of DCC and have overlooked a crucial component to enjoyable model railroading: the power pack.

Thank you, very much!
 
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