Gearing for Better Slow Performance?

Model Railroader General Discussion (Model Railroader)
1

I came across an 82 Model Railroader I was reading about better slow speed performance and using Ernest Gearing. I run HO Diesels. Has anyone done this??? as I would like some better slow speed performance out of my Athearns.

I have done all the cleaning jobs and even cut a half turn out of the brushes; still looking for that ultimate slow speed performance without spending $$$$ on the Newest Brilliant Technology even though I do get spoiled from the Wife sometimes.[:)]

thanks, Cary

2

I re-geared and re-motored (Sagami) this loco:

and four of these (Mashima):

using the Ernst gear sets, but found the latter four to be too slow for the road service for which they were intended. Restoring the original gears gave me the speed needed, but allowed them to still operate well at low speeds, too.

I later re-geared the first loco, too, as it was more useful when running at speeds compatible with the others - I’m running DC. The locos have been sold, but the gears are still around somewhere.

Wayne

3

Slow running performance depends on several things.

  • One is the proper motor / gear ratio. Most of today’s locomotives are geared OK with fairly good motors. So I don’t think re-gearing will improve things.
  • Another is the electrical side of things. When moving really slow, your electrical pick up has to be almost flawless. The problem is that dirt gets in the way. Dirt on the rails, on the wheels, on the wipers, etc. And most of the time you can’t see the dirt that is giving you the problem. And then there is the brush contact with the motor armature and the dirt there. When things are moving faster than a crawl, the dirt has less impact. When you really want the locomotive to crawl, then the dirt becomes an issue.
  • Then there is the physics of the motor. Remember the old law that said that “Things at rest tend to stay at rest”? Well, this applies to motors of any size including our miniature train locomotives. Sophisticated electronic controls can take care of that in our miniature world.

If you want that slow crawl in DC, re-gearing may help, but in the end, technology makes the biggest difference. In the 1980’s, there were several high end DC power packs and kits for power packs that you could build to get super performance were available. Power packs that has Pulse Power were the best.

Now days in DCC, it is the decoder that has the pulse power function, and now, BEMF has been added where the decoder actually senses what the motor is doing, and compensates for it. if you set these up correctly, you will get that slow crawling performance that you want. Each decoder has to be set up by you, the modeler, to be able to achieve that super slow performance. It is not plug-and-play. You have to work tweaking the different CV settings to get there. You have to study what the decoder manual is telling you, and experiment with the settings as each individu

4

The Earnst regearing kits work quite well on the Athearn BB drives (they also work on the early P2K Athearn clone drives). The main drawback with using them is that they won’t MU with locos with standard gearing any more.

5

As gandy noted. With today’s DCC decoders you can make a loco creap at less than 1smph. Make sure you get a decent decoder though.

6

I regeared an NWSL shay using a coreless motor and an inline reduction gearbox. It all fit in the space of the original motor.

Results:

  • Top speed of about 10 smph (about right for a shay)
  • Extremely gradual start-ups - You can barely see that it’s moving
  • Sound that makes you think it needs to shift to a higher gear
  • Realistic momentum action because coreless motors have a flywheel-like coasting capability.

I’m happy with the conversion and performance, but I can see that you’d have to be careful when regearing locos that should have higher speed capability. With gears you can easily reduce the speed capability of a loco to the point that even full throttle is too slow.

One way to get more realistic startup/slowdown performance while retaining high-speed capability is to use a flywheel on the motor shaft. It makes changes in speed more gradual. You do have to get used to the momentum effect - with a flywheel your trains won’t stop on a dime.

7

Have you a site for this conversion or a series of photos? I bet there are some who would like to know as they may use the idea for a geared loco, not necessarily the NWSL version.

Rich

8

Thanks for all the info; I do run DCC and mostly Athearn. The newest Athearns are very good but of course we all know on the older ones; just a few I was curious about re-gearing. Some I have converted with the newer Motors with Hex Drives via Ebay at a very reasonable price and they run very well. The Coreless Motors I did look into and would love to have but they all seemed to be in the 40-50 range ++$ for the extra parts needed unless someone can tell me where the Steals are?

I have programed a few Engines with the Startup/Slowdown performance but some of my Athearns seem to jump at Startup; seems like conversion for these few left and Coreless would be the way to go…!

Cary

9

no stranger to regearing here, been done on the Athearns with the Ernst drives. The early days getting slow speed performance has always been an issue, modding powerpaks to get that half-wave DC, powerpaks with the half wave switch and even a variable controller then powepaks that autmatically gave that pulse power on the low end. DCC has solved a lot of motoring and throttling issues and even going as far as simulating throttling issues. I regear switchers but not the road engines, but todays DCC pretty much regearing is not needed, when my BLI Y6b crawls at speed 1 setting, I am happy.

10

This is the web address for the guy who supplies my motors and gearheads:

http://micro-loco-motion.com/home.html

On my shay the power goes through a 2/1 gearhead, then a 10/1 worm/gear, then a 8/1 worm/gear, and then a 2/1 spur-gear/ring gear on the wheels. That’s a total reduction of 320/1 With the motor running at 20,000 rpm that’s 62.5 wheel revolutions per minute -