# Can I run 2 powered locomotives at the same time?



## Green River

Right now all have is a straight DC lay out with a cheepo blue Life Like transformer. If I wanted to run an extra long string of cars can I run 2 locos to pull like a real train if I had a better transformer? I tried it briefly today and the 2 just bogged the engines down not gaining much if anything. Someone told me once that a better transformer had more amps but I'm not sure what that would do for me in this case. Thanks for looking?


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## rosella

Yea mate a larger amp transformer is what is needed by the sound of it , the two locos are drawing more amps than your small transformer can supply.


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## Brakeman Jake

Two conditions to do this.First you need sufficient track current wich lower range power supplies lack of.

Then you can consist as many locos your power allows but you need to have locos with similar speed characteristics.Generally,same brands/models will usually have pretty similar speed,with only minor speed differences in wich case you put the slightly faster ones up front.Couplers are good at pulling,not so good at pushing.


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## Green River

Do you have any suggestions for a transformer upgrade? I know very little about them.


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## Brakeman Jake

MRC make good DC power suppllies.


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## DonR

You might check any nearby hobby shop or Craigslist for used
DC power packs. So many modellers are converting to
DCC that there is a glut of power packs. Perhaps one of
our members might have one suitable to power 2 locos
on your layout. I see them in stacks at train shows, usually
selling for 5 to 20.00.

Don


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## Green River

Do they make them that regulate power for grade changes so the train moves at a constant speed?


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## Brakeman Jake

This is called BEMF...a DCC feature only though.


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## Old_Hobo

Even real trains go slower up grades, until more power is added......


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## Green River

Old_Hobo said:


> Even real trains go slower up grades, until more power is added......


I don't mind the slow up hill climb, its the roller coaster ride over the hump that drives me nuts HA! What would a higher amp power supply do for me with a single engine on a flat track? Would it help the train run any slower or more consistent speeds? Seeing my trains run a steady scale like speed with a long string of cars would make me happy


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## Brakeman Jake

A DC power supply doesn't detect when more or less power is required for a given throttle setting,so there will always be differences in the uphill/downhill performances,no matter what you do...these are laws of physics.<

However,theoretically though,the situation might be improved somewhat.

Having a stronger power supply may reduce the tendancy of the train to slow down going uphill,supposing your actual one is too weak to push the extra energy needed.Then the downhill is another issue as it seems that the loco can't hold the train too well.Then adding a second engine MAY help in this case.Theoretically again,adding more pulling power should translate in more holding stength going downhill.

I never ran DC,going DCC right from the start...but the theory makes sense.


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## DonR

Theoretically, Jake you are right. If the power pack amp output is insufficient
for the loco it would be slower and the power pack would heat up.

However, voltage is the real speed control on a DC layout. Assuming good
track conductivity, when the loco slows on ascent it needs higher voltage, then
lower when it passes the hill peak. As Walter Cronkite used to end his
newscast, 'That's the way it is'.

Don


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## traction fan

*Hill climb/drop*

Greenriver;

You can make the train descend slower on your DC layout by making the downhill slope a separate electrical block. Install a plastic, insulated joiner in either one of the rails, up at the top of the grade. Install another insulated joiner, in the same rail, at the bottom of the grade. Use a resistor to connect power around the uphill insulated gap you have just created. When your loco crosses the gap, it will receive less power because of the resistor. This will make it slow down on the descent. You will have to try different values of resistor to get the desired speed. A good starting point would be the resistance of the locomotive. Measure this with an ohm meter, across the loco's clean wheels. 
This trick will only work when your train always goes down, on the same side of the hill. If it runs the other direction, it will climb extra slow and descend at full speed. It is possible to build a bi-directional version. Basically, you install insulated joiners in both rails, and a resistor around each upper gap. You will need to add a diode in series with each resistor. The two diodes should be installed facing in opposite directions. 
This kind of wiring challenge (and there are many others!), is one of the many reasons to switch from DC to DCC. If you are not absolutely glued to DC, I would strongly recommend changing to DCC now.
DC is not evil, or silly, or wrong. It's simply much more limited in what it can do. DCC will give you that smooth running you want, uphill, and down, and everywhere else.

Regards;

Traction Fan


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## wvgca

most transformers are well labelled, look for one with a higher VA [wattage] number, for two locos at the same time a VA of 16 or better is okay [about 1 amp output] ...


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## MtRR75

By his own admission, Traction Fan's suggestion gets pretty complicated. You could simply turn back the throttle as the train descends -- just as real engineers to. But if you want all of this to happen on auto pilot, you have to use Traction Fan's idea or go to DCC.

Also, note that if your train goes up an down the hill in both directions, even Traction Fan's plan will not give you total auto pilot control in DC -- you would still have to throw that switch that indicates which way the train is going to climb.


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## Green River

OK I had to put my trains on the back burner for a while but now I'm back at it. Which one of the MRC transformers would you guys suggest? I have been looking at used ones on line and prices are all over the place so it's hard to tell with that. I would like to have one I can pull long strings of cars and use multiple locos if possible.


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## MtRR75

Its been a while, so let's make sure that we are all on the same page first.

1. Are you staying with DC, or going to move to DCC either now or in the near future?

2. When you say "pull long strings of cars and use multiple locos", do you mean one long train with 2 locos lashed together pulling the train, or do you mean two long trains, each with its own loco?


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## MtRR75

Regarding train length: The train length that you can pull will not be affected by what transformer you use (as long as you stay away form the small ones that come with train sets). The four factors that affect maximum train length are: (1) engine pulling power, (2) weight of cars, (3) rolling resistance of cars, and (4) grades.

(1) Engine pulling power varies from loco to loco. The only trend is that heavier locos sometimes can pull more weight because of their greater friction on the track. But this is not always true; there are other factors in loco design that affect pulling power. It is easier to focus on the cars.

(2) Weight of cars is tricky. Heavier cars stay on track better. But heavier cars also shorten the train length that you can pull. There are standards as to how many ounces a car should weigh (which have been posted here many times), and some modelers strictly adhere to these standards. But my philosophy is that if the cars are staying on track, I don't add weight. If they derail, I first make sure that all other possible reasons for the derailment have been checked, then I add small amounts of weight at a time, until they stop derailing.

Also, if you have a mixture of heavier and lighter cars, put the heavier cars nearer to the front of the train, and the lighter cars nearer to the rear. If you reverse this, sometimes the weight of the rear cars can pull the lighter cars off of the track when they are on curves.

(3) Rolling resistance is where I feel that you can make a big difference in the length of a train that you can pull. In order to maximize my train length, I test the rolling resistance of all of my cars, then use those with the least rolling resistance first to build my train.

I test the resistance by comparing one pair of cars at a time and make a list of where each car falls in the rolling resistance ranking.

To compare two cars, I put them on a flat, level straight track about a 3" apart. I use a piece of soft foam that is about 6" long. I rest the foam on the ends of the two cars -- like a bridge. Then I hold the foam and move the cars along the track at as constant a speed as I can, and lift up the foam to release the cars. One of the cars will usually pull away or catch up to the other one.

I find that I need to repeat this several times, as the results vary -- probably because I do not keep the foam moving at exactly the same speed as the cars when I pick it up. I also find that I have to do this in both directions. The trailing car seems to get a slight advantage -- maybe either because of less air resistance or because of the way that I pick up the foam.

To improve rolling resistance, I try the following: (a) use a truck tuner on the trucks to clean out and shape the notches that the wheels fit into, (b) replace wheels with better quality wheels, (c) lubricate the wheels, and (d) replace the trucks, if all else fails.

(4) As for grade, obviously, the steeper your grade, the shorter your maximum train length will be. But also the more curved your grade, the shorter your maximum train length will be, since curves also add rolling resistance over that of straight track. Also, if you have grades, try to make up your train out of your lighter-weight cars, so that there is less weight to pull uphill.


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## DonR

Very complete discussion of train length calculations
by MtRR.

There is one additional factor: curved track. The rolling
resistance increases substantially as the wheel flanges
rub against the rails, the tighter the radius the more
resistance.

There is an interesting array of MRC power packs offered
now on line: There are powerful ones in this group.

http://www.ebay.com/sch/i.html?_nkw=mrc+power+pack

Don


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## CTValleyRR

A review of some basic concepts might be worthwhile here: a DC transformer supplies a variable voltage to the track, depending on where the throttle is set. Any and all locomotives drawing power from that section of track will move at a constant speed (although each motor will be a little different). Grades, loads, friction, etc., will change that speed unless the voltage is changed at the transformer.

DCC provides a constant track voltage, while a small microchip (a decoder) inside the locomotive varies the voltage drawn by that motor to maintain the parameters set by the operator. The parameters are set individually for each locomotive, thus different speeds / performance characteristics are possible for each, no matter how many (within the capacity of the system) are on the track.

It sounds to me like DCC is more suited to what you want to see on your layout.


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## Green River

To clear things up I plan to stay with DC until I get a better place to set up my layout (we will be building a new house soon with a basement). My plan was to set up a coal train with 2 or more locos pulling it like want use to run through my home town growing up, it's just something I have always wanted to do. The starter set transformers I have now are OK for what they are I just know they lack power for more than 1 loco. I have 4 L&N Athearn SD40-2 that I would love to see coupled together pulling a coal train, would a MRC transformer make that happen?


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## DonR

The MRC 700 listed here with a top bid of 30.00 is exactly
what you want. It is rated at 4 amps. Adequate for
3 or 4 locos to pull your coal train in from the Dakotas.

Hurry tho, only 4 hours til sold.

http://www.ebay.com/itm/MRC-Model-7...T-CONDITION-/271941997786?hash=item3f510194da

Don


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## MtRR75

Green River said:


> I have 4 L&N Athearn SD40-2 that I would love to see coupled together pulling a coal train


Once you get your transformer, test the speeds of your locos. Put them on a section of straight track separated from each other. Apply power and note which one is the fastest, second fastest, etc. Then lash them together in speed order with the fasted first, and the slowest last. This way the locos are helping each other instead of fighting each other. Each one pulling a little on the one behind it, allowing it to travel a little faster without losing any of its pulling power.

P.S. How may coal cars do you have, and is your layout large enough for a really long train? The engineer in the lead loco should not see the end his own train ahead of him.


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## Green River

I missed the auction on that one, just got home from work, it was a hot item at 23 bids. What else can I look for?


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## DonR

Green River said:


> I missed the auction on that one, just got home from work, it was a hot item at 23 bids. What else can I look for?


I would keep an eye on Ebay and Amazon. As modellers upgrade to
DCC or the unfortunate case of an estate selling a layout more and
more Power Packs will be offered.

You might put a free 'ad' here on the for sale or trade section
saying you want a DC power pack that will have enough
amperage for your trains. 

Don


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## Green River

All this searching on ebay and reading this forum makes me think I should consider DCC?? Not sure where to start.


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## MtRR75

Green River said:


> All this searching on ebay and reading this forum makes me think I should consider DCC?? Not sure where to start.


Prepare to be overwhelmed with TMI on DCC.

But the very first thing to consider is -- are your existing locos "DCC ready" or not. If yes, then you will need to buy controller cards and install them -- not very hard -- they plug into the inside of the loco.

If no, then you can still buy and install controller cards, but you will have figure out where to put them under the shell and do some wiring inside the loco.


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## DonR

Start by reading the various posts in the DCC and HO forums. You'll
find several discussions of which DCC system to consider.

Since you already have two locos you may want to get only
the DCC Controller with a 1 or 2 amp power supply. My 1 amp
Bachmann EZ system routinely powers 4 locos running at the
same time. That is 2 GPs pulling a freight and 2 FAs pulling a train
of lighted passenger cars.

Decoders for locos run 20.00 each and up. But they usually limit
the loco motor draw to less than 1 amp so it's imperative that
you do a stall test to determine how much current your locos
are pulling if they are not DCC ready. 

Don


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## MtRR75

DonR said:


> Since you already have two locos you may want to get only the DCC Controller with a 1 or 2 amp power supply.


According to Green River's post at the top of this page, he has FOUR locos that he wants to lash together.


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## Green River

Kind of an interesting afternoon. Back in June we had the US68 400 mile yard sale, I found a box of HO trains and accessories for $15. I got the box home and inside one of the items was a Life Like B&O (GP-30??) locomotive, I put it on the track and it did not run, OK fine put it in the box and MAYBE some day I will pull it out and see what the problem is after all it's just a cheepo Life Like. Well today was the day to look at the cheepo -loco so I removed the shell expecting to find a broken wire, corroded contacts or a burned up motor, to my surprise the loco was actually DCC....I think? What do you guys think isn't this a decoder? Anyway I'm thinking this is a Proto 2000 maybe set up from the factory to run on DCC? Now I'm really leaning towards changing everything to DCC, it's really spiked my interest in DCC!


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## DonR

Tho I can't read what is printed on the device, It's shape and
the color and number
of wires does lead me to agree, you have a very good
quality DCC locomotive. Is there a jumper present to enable it
to run on DC? Some locos have that.

You got quite a value for 15.00 if it runs.

I did failed to pick up on the fact you want to
consist 4 locos. Not a problem even with the 1 amp
Bachmann EZ. I run 4 locos at the same time often
on mine. But you still may want to consider a
more powerful DCC system, especially if you
expect to run sound.

Don


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## tr1

*Poor conductivity*

sounds, like you have dirty track or wheels in need of a thorough cleaning. Maybe some more drop wires or feeder wires, need to be added. Plastic wheels may attract dirt, due to there static charge that is produced by there rolling friction. So they .say. Good luck, fine tuning your layout for trouble free op. sessions. Regard's,tr1


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## Cycleops

Certainly looks like a DCC decoder in there, a Bachmann on a eight pin plug. You'll need a DCC controller to run it. If you want to do it on a budget Don can give give you a run down on the Bachmann EZ system. Loco looks good with nice fine handrails and detail.


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## Green River

The locomotive is definitely a Life Like says so on the bottom of the tank, although the decoder says Bachman. Can any decoder run with any DCC system? I know very little about a DCC system. I was looking at some of the Digitrax stuff on Ebay but there was a lot of stuff an was pretty confusing, maybe I need to start with a starter pack with everything I need? Can sound be upgraded to any system?


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## Cycleops

Green River said:


> Can any decoder run with any DCC system? I know very little about a DCC system. I was looking at some of the Digitrax stuff on Ebay but there was a lot of stuff an was pretty confusing, maybe I need to start with a starter pack with everything I need? Can sound be upgraded to any system?


Yes, with certain reservations any decoder can be used with any loco. Most decoder makers have a compatibility chart of some sort to help you. By all means buy a starter set which would include a power supply and controller. You can add sound to most locos but the cost is going to be around $100+(not including the loco). Available internal space for the speaker is the limiting factor in most cases.


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## MtRR75

Cycleops said:


> You can add sound to most locos but the cost is going to be around $100+(not including the loco). Available internal space for the speaker is the limiting factor in most cases.


Of course us steam guys can always hide the speaker in the tender. But that got me to thinking (dangerous, since I know nothing about diesels). If you could live with always having a certain box car as the first car in our consist, could't you put the speaker in the box car -- if no other place was available? Might have to cut some holes in the bottom to let the sound out. Just wildly speculating about something that I know nothing about.


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## DonR

Most DCC devices are built to NMRA standards so basically you
can mix and match between brands. However, if you have a
Digitrax Controller, for example, you must use a Digitrax hand held. Same
with other makes. 

Don


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## Green River

How much will a starter set run me?


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## DonR

They're all over the place money wise.

For example, look at the variety now on a Digitrax starter.

http://www.ebay.com/sch/sis.html?_nkw=Digitrax+Zephyr+DCC+Starter+Set

You can get the same choice with NCE and Bachmann also.

Here's a current offer on a Bachmann EZ DCC controller.
This is what I have.

http://www.modeltrainstuff.com/Bachmann-44902-EZ-Command-DCC-Control-System-p/bac-44902.htm



The typical DCC decoder for your locos will run around 20.00 to
30.00.

Don


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## Green River

Will a 3 amp set up run 3-4 locos?


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## DonR

In general, DCC HO locomotives when running fast will draw .5 to .7
amp. Sound locomotives will draw more. When they run slow the
amp draw is much less.

A 2 or 3 amp power supply will easily power 4 DCC HO locomotives.

As I've said so often, I regularly run 4 locos, and sometimes more,
at the same time on my ONE AMP Bachmann DCC system.

Don


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