Hello everybody,
my issue is that most of my locomotives are either Kato or Atlas that operate in DC. The locomotives from these two manufacturers get MU'd all the time, but in my collection of loco's there is a pair of P2K SD45's. These engines run a lot faster then both Kato or Atlas engines, due to the gearing.
My question is has anyone made the P2K slow down to better speed match with the Kato and Atlas engines, while in DC? I know that in DCC one can program to match the speed curve of the engines but that is impossible in DC. My current attempt is with a pair of diodes in Series. This makes the SD45 start later, but match speed in my hauling speed range. At full throttle the SD45 still outruns the other locomotives.
Anybody with any ideas?
Thank you
Frank
"If you need a helping hand, you'll find one at the end of your arm."
I used to put a resistor or two on one of the motor terminals so power from the track had go through the resistor(s) to get to the motor. I don't know much about resistor values. I just used whatever one did the job.
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Thank you jeffrey-wimberly. Right now I have done basically the same thing but with diodes. I am afraid that the resistors would get too hot. The diodes stay very cool, but resistors would give me better running qualities then diodes, because diodes have first to reach the threshold voltage before they let any current flow. Will have to look for resistors with a large enough watt dissipation capability.
OK. I have a similar issue with two locos that I MU, on my DC layout. They are close enough in speed that it works. I put the faster one in font and I am not happy thinking that the second one is holding back the front one. It can't be good? However, the most difficult electrical work I have ever done is wire my layout without burning down the house and I wired it 18 years ago, when I had far more brain cells. What do you mean by "Will have to look for resistors with a large enough watt dissipation capability?" Would doing something like this help me match the locos?
Thanks,
Glenn
I'm with Frank & the guys on this, back around '2KY' I had 2 Kato's & then introduced an Ath FP45 into the mix. The Kato's had a smooth startup & even smoother throttle response. The FP45 (doesn't really matter who's it is), was different, but OK on it's own. After doing a break in period & proper lubrication, they would not be a cohesive unit. So, I decided to try adding a resistor into the motor leads. I started making progress. ( I was running these on a 10Ft (effective [12' total]) Circuitron auto reverse track, backed with an MRC TechII pack) I finally found a resistor value that somewhat matched the performance of the Kato's, but it did did not match in all respects, but, was close in the speed I would 'likely run them!' So, once I found that resitor value, I needed to see if I could make it work under the actuall shell! ( had been running it without the shell to test resistors.)
Here is the issue: I had been testing with the common 1/4 watt resistors, to consistently run this unit I would need at LEAST a half watt resistor, or a 1 watt unit. The issue is how much power can 'safely' pass through the resistor without it burning up due to heat dissapation. Think of a resistor as a *** across a creek. It is not very large, & the force upon it is not that large. However, that same *** in a flood or in a river may breech, & fail.. This is the same concept that is happening in our Locomotives! If with all our power Motors, Lights, DCC, Sound, etc. we may draw more than the resistor can handle, & it will TRY to handle it until it burns up melting the shell & other things. So, a larger wattage resistor can handle more amperage, & maintain it's cool temp better than a stressed out little guy.. Same thing works for 'circuit breakers' don't try to run a 20amp load on a 10amp breaker, it's much better to run a 10amp load on a 20amp breaker.. I hope that helps a little..
I finally decided to run the FP45 on a seperate unit train, & with the addition of a (back then) constant lighting unit, it was/is a pretty good unit.
HI,
thank you Glenn and Chad for the replies.
I have also done some more testing on my P2K SD45. I found that 11 ohms is a good value for speed matching the locomotive with the Kato units. Now it is a matter of finding a 2 watt resistor. I believe that 2 watt resistors will stay quite cool inside the shell of the unit.
I will hold back the loco and measure the voltage drop at max speed and max exerted tractive effort tonight. This will give me max voltage drop across the resistor and max current draw. From that it is easy to calculate the wattage of energy used by the resistor and post the result tonight.
Frank,
A few thoughts. Are you pulling enough cars to actually need all thes locos? The reason I ask is that I find pulling heavy trains with slightly mismatched locos double/tripple headed is not a problem. The weight of the train evens things out.
I don't have any of the locos in question since they are wqay outside the era I model. But I have lots of locos of different brand that I double head, as long as they are close I find it works. But close can be deceiving when running them free - have you simply coupled them together and tried it out?
If one id truely dragging or pushing the other, than it is time for some resistors and you are on the right track with that.
I run lots of mixed steam - different brands, different wheel arangements - most work fine.
Sheldon
Hello,
thank you for your question, Sheldon. My current layout is one where I wanted to find out about grades and helix construction. My room for my layout is 9 feet by 11 feet. In this room there are 3 main levels of layout connected with a 5 foot diameter double tracked helix along with 4 storage tracks. It took a while to get a lot of the kinks worked out, while others I can live with but these mistakes will not be repeated on the next layout, like a S curve at the top of the helix. This can created some serious string lining on 40 car freight trains.
As a general rule of thumb my main line freights are 18 to 24 cars and the locals are no more then 8 cars. The locals get double headed and the main line freights either get triple headed or double headed with a pusher .
The P2K SD45's are beautiful locomotives, but HEAVY and too fast compared to my Kato engines. Being in DC only I find it a shame that in my opinion these locomotives are a bad speed match with the Atlas and Kato and re-wired Intermountain locomotives. Also had a SD45 pull a freight one time where a car got hooked on a switch machine, this happened at a slow speed and I thought the electric motor was going to burn out, this was due to the high weight of the locomotive giving it so much traction. So to sum it all up I would like to find a solution to enable these engines to enter regular service on my layout that has more track on a incline then on the level without burning out the motor.
Also got a Bowser C-630 and this engine is faster then the P2K SD45's and the Athearn RTR SD60 also needs to slow down which got me thinking that this is a good project to tackle.
As for steam locomotives, from which I have two IHC 2-10-2's and a P2K 2-8-8-2, I find that they pull so little that it does not matter if they are speed matched. These locomotives are light enough that if they spin their drivers there is no fear of them burning out the motors. I wonder if their lack of pulling power has something to do with their long wheelbase, which on my uneven track prevents all the drivers from getting good traction?
I will post my final decision on which resistor and watt range which go into each locomotive for those that are interested.
Frank, it sounds to me as if most of your trains don't really need to be doubleheaded. Most of my steamers (Mikados and Consolidations) will pull 16 to 20 cars (most of which aren't particularly free-rolling) and my railroad is mostly curves and grades. With longer trains, some parts will be going uphill while others are going downhill, and curves can be both left and right, so for heavy trains and/or long ones, power has to be doubleheaded and sometimes trains also require a pusher. As Sheldon has mentioned, if the extra locos are really required to move the train, the speed issue pretty-well takes care of itself.
I'm not familiar with most of the locos you mention, but I don't recall seeing an unmodified loco that wouldn't slip its wheels if its train was too heavy, unless, of course, it was fitted with traction tires.
I wish you luck with the resistor solution, but I'd look at your dilemma as an excuse to buy more rolling stock: if one of your locos is all that's really required to move a train, you have an imbalance in the ratio of cars to locos. Increase the number of cars available so that each loco will have its own train.
Wayne
doctorwayne Frank, it sounds to me as if most of your trains don't really need to be doubleheaded. Most of my steamers (Mikados and Consolidations) will pull 16 to 20 cars (most of which aren't particularly free-rolling) and my railroad is mostly curves and grades.
Frank, it sounds to me as if most of your trains don't really need to be doubleheaded. Most of my steamers (Mikados and Consolidations) will pull 16 to 20 cars (most of which aren't particularly free-rolling) and my railroad is mostly curves and grades.
I believe that the OP was talking diesels. A steamer with 16 to 20 cars looks like a train. But in my somewhat biased opinion it takes two or three diesels to accomplish the same thing. I think it is a matter of appearance rather than actual necessity.
Regarding the use of resistors, I think that will only work if the locomotive in question has a relatively linear speed curve. I have recently found some model diesels where the low end speed curve is relatively flat and linear, while the upper end slope is non-linear and steep.
And I don't necessarily agree with the idea that putting two or three engines together in a train will make unmatched engines work together well. If we assume that one loco will pull that 20 car train with no problem by itself, then any other loco or locos is basically going along for a ride. So the slower speed heavier engine will be pulling the train and pushing/pulling the faster speed lighter engine. The fast/light engine will be moving along all right, but is really just spinning its wheels wearing off the plating. And you won't notice this unless you happen to be listening for that grinding sound as the train goes by.
And there is a speed difference between manfacturers. On my speedometer I find, for example, that Atlas locos seem to have a top scale speed of just over 80 mph, while some Athearns are 100 mph and up. There is just no way that these locos will play well with one another without some modification.
thank you for the replies. As for double or triple heading the trains, it is not for show, but a necessity. A 30 inch radius helix with a 2.2 percent grade really reduces the pulling power of the locomotives. It does take two six axle diesels to pull a 20 car freight up the grade, and believe me the locomotives are working. As for the steam engines, the Walthers/P2K steamer with the 2-8-8-2 wheel arrangement will have a hard time with 7 freight cars up the helix. I could not believe the effect the helix had on the locomotives pulling ability either, because my other layouts were all flat and pulling a 20 car freight with one locomotive was quite normal.
Thank you for all the replies
A few more thoughts:
First that is a steep helix and the combined effect of curve and grade does create a lot of drag.
Second, I don't know what kind of equipment you are running, but I have had great success increasing pulling ability with free rolling trucks. I have my own special formula because I like sprung metal trucks.
I install Intermountain wheel sets in Kadee trucks and very lightly oil the journels at installation.
This makes for a better tracking, more free rolling car than anything I have tested - and I tested a bunch.
Steam locos, real and model, do loose a lot of pulling power in curves and loose it faster on grades than diesels. If you have not read it, you may want to check out my comments in the recent thread about keeping pilot wheels on the track. A lot of what is discussed there applies to pulling power as well.
I would recomment BullFrogSnot for those locos, they need some grip and adding weight to them is not very easy.
My view with any double/tripple head combo in DC is simply try it first, even if they seem unmatched running free. Sure, you don't want any actual dragging, but short of that, if they run together, run them.
maxman doctorwayne: Frank, it sounds to me as if most of your trains don't really need to be doubleheaded. Most of my steamers (Mikados and Consolidations) will pull 16 to 20 cars (most of which aren't particularly free-rolling) and my railroad is mostly curves and grades. I believe that the OP was talking diesels. A steamer with 16 to 20 cars looks like a train. But in my somewhat biased opinion it takes two or three diesels to accomplish the same thing. I think it is a matter of appearance rather than actual necessity.
doctorwayne: Frank, it sounds to me as if most of your trains don't really need to be doubleheaded. Most of my steamers (Mikados and Consolidations) will pull 16 to 20 cars (most of which aren't particularly free-rolling) and my railroad is mostly curves and grades.
Yeah, I was aware that we were talking about diesels, but my point was that if the extra locos were strictly for show, there'd be much less chance that they would speed match than there would be if all locos were needed to move the train. It usually matters little that two locos running independently on the same track don't run at the same speed, but with a train heavier than can be moved by the more powerful of those locos, the two together will work together to move the train. My layout has a lot of grades, and the majority of them are 2.5%, and all of them are on curves, albeit 34" radii.
I am surprised that it would take two large diesels to move such a short train, 2.2% grade and 30" radius notwithstanding. I expect a pair of steamers (or SW-type diesels, when I still ran them) to move a 13 car train weighing 100 oz. (probably close to the weight of Frank's 20 car train) up any of the grades on my layout, and that includes one that's 45' long and comprised of two horseshoe-type curves (totalling more than 360 degrees) and a wide-radius s-bend.
Frank, if the resistors work out, your problem is solved, although if extra locos are, as you say, required to move the train, your mis-matched loco speeds should level themselves out without modification. If they don't and the resistors don't offer a solution, then your next best option is to assign locos based on their speed characteristics: fast locos only with similar ones, and likewise for slower locos, even if it means buying more locos in order to have enough matched sets to move your traffic.
Hi Sheldon,
thank you for your comments. You are right, some BullFrogSnot would certainly cure my pulling issues on a helix.
You have a interesting formula for creating free rolling trucks. I own the axle reamer and also put in new wheel sets so that they are all made of metal on all of my rolling stock. As it is right now the Kato trucks roll the best from all of my rolling stock. The rolling stock being made up of freight cars from Atlas, Walthers, Athearn, Intermountain and Kato. I really have no desire to purchase Kadee trucks and put them under all of my freight cars, instead I fiddle with the rolling stock to make it run better. Feel I have paid enough for them the first time around.
I will re read your comments on keeping the pilot wheels on the track. It is very tempting to just put more lead in the steam locomotives to get them to pull more,. but not having any experience in that field might make it a dicey proposition.
Double or triple heading is great if the locomotives all match in speeds, otherwise, and this has been happening, my Kato and Atlas locomotives are just about the get going and the P2K's are spinning their wheels.
Again, thank you for your comments.
Hello again,
for those people that are interested, the resistors have been added to the locomotives and they all are speed matched now. To do this I purchased 2 Watt resistors, 2 Watt is what is required to be able to dissipate the heat from and the resistance settings are as follows:
P2k SD45 used 11 ohm resistors
Bowser, latest run of the Alco C630 used a 13.5 ohm resistor.
Still have to do some more work on the Athearn RTR SD60 to get it to run right with a resistor added
Hope it helps.
Great work Frank! I will have to watch for the 2 watt versions, I used small ones in testing but they almost turned into light bulbs.
Thanks for the tips & update!
Hi Chad,
here are a couple more items to consider:
First off there is a web site which can be used to calculate the value of resistors in parallel, it is http://www.csgnetwork.com/parallelresistcalc.html . Please keep in mind that if you take two identical resistors and wire them up in parallel the overall resistance is cut exactly in half, but the wattage is the result of both resistors added together. If you put two resistors of different value in parallel, then the result will be a overall resistance lower then the lowest resistor. Hope this makes sense. The resistor with the lowest resistance will pass the most current in a parallel wiring scenario.
Also the way I came up with a wattage value for my resistors was by simply putting in a 2 watt resistor into the P2K SD45 and putting the CMX clean machine behind it. This made the locomotive spin all the way around the layout. After a couple of trips around the resistor did not increase in temperature to any noticeable effect.
The small resistors that turned into light bulbs were probably 1/4 watt resistors.
Hope this helps some more.
Hey, thanks for the refresher, it's been a while since I went 'parallel' with them, but my class teachings echo your advise, & reminder!
Yeah, the CMX 'drag' test should be the tip of the day!! Excellent!!!! Love that!!
Yeah they were 1/4W at best, but they valued out to what I will need for a future permament install! I know my Dad has a big dial 'variable' resistor from his Ham Radio (& electrical influence) days. So I will try to bargain that out from him..
On your Athearn; I think that may be a gearing difference, I know I had 2 SD40-2's that I put the Ernst gear reduction kits into & numbered them so I would (hopefully -but don't) know they were consisted to each other, & not other brands. It really made them slow down & pull harder, but way different characteristics than an Atlas/Kato set!
Thanks again Frank!