Engines run differently


Sweet-Chuck

Sweet-Chuck

Member
Question for you all:
I have a few different locos, Athearn blue box, life like, Bachman, and an unknown.

They all run differently on the same track, same power pack. When turned "all the way up", the Life Like will literally go so fast that it will nearly go all the way off the track on curves. The Athearn, however, on "full speed" is quite a bit slower...almost half the speed of the Life like.
'The bachman is a bit faster than the Athearn.

What gives? I would think that the Athearn, being of better quality should run at a higher speed than what it does.

Thanks,
 
The usual measure of quality for scale model trains is how slow and smoothly they will go. It's easy to get something to go fast but make it run smooth and slow takes finer precision.
 
"full speed"

you know, something told me to make sure (in my original Post) that I DO NOT run them at full speed!

I was simply stating that at full speed all of the locos run differently. :)
 
In almost all cases the cheaper locos (Athearn blue box excluded) have cheap drive lines and small high speed motors. They usually don't perform well at slow speeds. The more expensive locos have larger, better made lower speed motors and better made drives. The Athearn blue box locos usually need some work to "clean up" their gears and motors so they run at their best. At the low price they were sold for many people didn't mind putting the extra work into them.

Many times when I had locos from different manufacturers that I wanted to run together I would put a resister or two in the faster one to slow it down.
 
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The various manufacturers specify what they want in the way of drive mechanisms, and eventually they contract with the cheapest supplier to provide their assembly factory with the drives.

This means that the drives will have different specs, not the least of which will be the motor's responsiveness to changes in voltage, and also the gear reductions in the gear tower. Some locomotives were slower drag engines in their real lives, so you would think the sellers would arrange to have them operate at a slower track speed generally, but they sure as heck wouldn't be able to keep up with an Accela or TGV at the same 8 volts. But, it doesn't mean that it is really the case.

Simply, you are seeing the varied responses, and capabilities inherent in their design specs, of the various drives to a given voltage output at the rails. If we can assume the trailing cars weigh about the same for all the trains, and there are no substantial grades or tight curves, and all the trains are therefore under the same general conditions, and you see quite a range of speeds with the voltage cranked right up high, then those are real limits for each drive system.

It could be, though, that your drives are sticky, as Jeffrey suggests, and they need cleaning and new lube. It could also be that the motor windings or brushes need some work because as they are, they can't really run to peak performance.
 
What is more aggrivating is when two "identical" engines from the same manufacturer won't run at the same speed! Especially with diesels, for those who tend to run m.u.'d units with two of them powered, rather than a powered one and a dummy. With DCC, you can adjust the speeds by altering the CV's applied to speed. But with DC locos, it is a pain in the klarn! As was posted above, you can try to break the two units in, clean up any burrs on the gears, etc., but if the speeds are considerably different, you may need to insert a fixed resistor or a small potentiometer in series with the motor leads to get the beasties to match speeds.

As was also posted, variations between prototype locomotives of different types or classes, depended on the purpose to which they were put. Steam locomotives' drivers were of different sizes depending on whether they were intended for swtiching, slow drag (smaller diameter drivers) freights, larger for higher speed freight service and also high speed passenger service. Occasionally, one locomotive was used in dual service. The Burlington Route's O-5 class 4-8-4's were especially versitile in this manner.
 
Sweet-Chuck said:
Jeffrey, what do you mean by "clean up" the gears?
Click to expand...
Disassemble the trucks, remove the gears, carefully remove any obvious burrs or flash from the gear teeth, reassemble the trucks, put in Pearl Drops tooth polish or another fine abrasive suspended is a semi-liquid solution. Run the loco on a break-in forward and backward about 15 minutes in each direction then disassemble the trucks again and clean them out. Put them back together and put in your regular lube. The abrasive should have burnished the gears smoothing out any rough spots and help the gears mesh more smoothly.
 
Sometimes swapping the gears around, also helps. I also remove several coils from the brush springs. Also, Athearn blue box engines have very little weight, thus adding more weight will help slow them down. I am assuming the Life Like is of the toy train variety and if so there isn't much you can do to slow it down except maybe shoot it. Most of my blue box Athearn engines will run with my P2K's engines Phil
 
trailrider said:
What is more aggrivating is when two "identical" engines from the same manufacturer won't run at the same speed! Especially with diesels, for those who tend to run m.u.'d units with two of them powered, rather than a powered one and a dummy. With DCC, you can adjust the speeds by altering the CV's applied to speed. But with DC locos, it is a pain in the klarn! As was posted above, you can try to break the two units in, clean up any burrs on the gears, etc., but if the speeds are considerably different, you may need to insert a fixed resistor or a small potentiometer in series with the motor leads to get the beasties to match speeds.
Click to expand...

Usually the difference is caused by the brushes getting gunked up. If the motor brushes are gunked up, it will take more power to get the loco moving. The other thing is the gearbox. Some gearboxes have more lube than others. Another thing is that motors aren't always made the same due to the materials used (magnets).

As for running different brands together, each brand has their own drive system, and their own motors. The gear ratio may not even be the same. For example, Athearn uses mostly 12:1 gearing due to the fact that they've standardized on it long ago, and are using the same trucks on different models. If and when they need to design a new truck (such as when they came out with the SD50s and SD60s) then they would use the now industry standard 14:1. As for motors, Atlas and Kato both use a 14:1 gear ratio, but the Atlas will run slightly faster than the Kato due to the different motors which rotate at a different RPM at the same voltage.
 
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