Motor/Gear upgrades for Locos

I figure this might be a good topic for those who like to improve engine performance with better motors and/or gear combinations. I have done an Athearn RDC with an Ernst gearset with great results. I picked up a used Brass 0-8-0 a few years back. It had an old open frame motor with worm directly applied to the axle gear. Needless to say, it didn't run very well. I put in a Mashima (NJ international at the time, now A-line/Proto Power West) flat can motor flywheel and a 36:1 NWSL ider gear box. Using Athearn universal parts, the engine runs great with a better prototypical speed range. I also repowered an Brass C&O H8 Allegheny for a friend of mine years ago with a NWSL can motor, big difference; smoother running, better speed range.

What's your experience?

Bob

No experience but I do appreciate the heads up on the RDC rubber band drive.

Your experiences with steamers parallel mine, I put a can motor kit with idler gear in one of my Mantua 4-6-2's and was very happy with the results. Some of the new brass diesel-electric locos can use similar help. I bought an OMI GE AC6000 about a year ago. The appearance and detail are just superb. However compared to my Kato locos the run quality was absolutely rotten. The power would cut out in curves, low end creep was lousy, and it was noisy. After much screwing around including calls to the distributor it became obvous that the little wire pickup whiskers that drag on the backside of 4 of the wheels on each truck were the problem. Kato uses plastic truck frames with a very nice copper axle bearing/ conductor bar to feed power to the motor. Further, we found that this expensive piece had a 3 pole non skewed armature motor.

Long story short; we machined and refitted the frame then installed a complete Kato drive. The details on the plastic truck side frames were milled off and replaced with the brass counterparts from the original. The Kato frames even have the foundry markings on them. Detail is actually improved. It now runs as good as it looks.

I always wondered why brass dealers always demonstrate on a straight piece of track. Now I know.

I've found Brass loco's of pre '90's era are generally fair to poor runners. More expense was put into the metal work and details then on the motors and gearing. When can motors and idler gearboxes were introduced, brass engines manufactures began to improve the drive mechanisms but, there are a lot of '60, '70 and '80 engines out there that need upgrading. I think the reason many older brass locos are not modified is most owners don't like to run them except to test or show off the engine.

Hostler wrote that older brass generally didn't run too well. My AC-6000 is not older brass. It's vintage 1999, and still was a lousy runner. The Buhler motor with a 3 pole straight armature was the real surprise. Cheap stuff for sure.

That 3 pole motor in a recent made brass engine is really surprising. I would have thought that can motors, flywheels and idler gear boxes and good running mechanisms would be the norm. I guess not every manufacturer is concerned about the mechanism and quality of its brass engines. My feeling with present day brass, is if you built it with little care for a fine running mechanism, what kind of quality went into the metal work and detailing of the engine. Kind of like building a high end Mercedes and putting a lawnmower engine in it. To build a brass engine and put a motor that basically dates back to the 50's doesn't say much for that company. Most of my brass is late 60's to early 80's make and I haven't bought any recent made engines. Seems we still have our work cut out for us to get our brass engines running as good as they look.

A little FYI on steam loco gearing. Typically the driver diameter was the determining factor on a loco's speed. Drivers of 68" and above could be run a higher RPM and generally freight drivers of 63" and less was a good indication of the engine's top speed. Engines like the PRR K4's could do 100 mph, that's about 1.20 x driver diameter (84" drivers). Applying this to loco drive speed, that's about 310 RPM for freight (speed equal to driver size) and about 420 rpm for passenger (1.25 x driver dia). Some engines like the N&W J's with 72" drivers could exceed the 420 but the engine was well balanced. If you take your motor RPM speed (this is ususally the no load max) add the gear box ratio, you end up with you driver RPM. Unless you want you passenger engines to really reach those very high speeds, you'll find a 310-350 RPM range very good. If you have a switcher, use a lower RPM, around 250 because these engine never ran more that 35 mph anyhow. I've found the NWSL 28:1 good for passenger/freight engines (your speed will be about equal to driver diameter) and 36:1 for switchers. Also note the motors under load may not reach their no load speeds. Another consideration, less wear and tear on your locos running gear as well as smoother operation.

Can anyone suggest changes to the Ernst kit, i.e., that would change the reduction from 3 to 1, -- to 2 to 1, by retaining one or more, of the original Ath gears?

Does an idler gear, in effect, cause a reduction in gear ratio?

For steam locos, the old designs had the motor at an angle contacting the worm with the worm gear that was mounted on a driver axle. This caused the driven axle to be thrust to one side in one direction and the other side when reversing direction. Also you couldn't spring the drivers. Take a NWSL idler gear box, the idler gear is actually the worm gear driven by the worm. This is your actual reduction. Determine how many full turns the motor turns per one turn of the gear and that's your reduction ratio. Now the worm gear (the idler) takes all the side thrust, the idler then meshes with the gear on the driver axle which puts out little or no side to side thrust. If the gears are the same size, the idler/worm ratio is you total gear reduction. If the driver gear is smaller, you reduce the intial reduction (speeds the axle up a bit). If the axle gear is larger than the idler, than you'll have a further gear reduction. The idler gear box also allows sprung axles.

Diesel are a bit different. Due to the smaller wheel diameter, the axle gears are small, so you lose some of the intial reduction as the intermediate idler is usally larger and speeds up the axle. Diesel engines usually use a double idler system needed to transfer power from one input to two outputs. If the worm gear and axle gear are the same, than the intermidiate idler has no effect.

I haven't tried this yet. But plan to once I start to remotor a few of my old Athearns. I have been told these are good motors and cheaper then A-line and NWSL. Here is the web site.

http://www.alliancelink.com/alp/photos.htm

I hope this helps someone.

The A-Line motors are Mashima motors. Years ago they only had a few round and three flat can motors, basically 24, 30 and 36mm long. I believe NJ International used to sell them years ago. If I remember correctly, they had a bit longer shaft than the A-Line and they were cheaper that the NWSL units. If you can find old Mashima's, you can't go wrong, they were sometimes available for $10 - 15 dollars a piece sometimes even less. Although the Earnst Gear sets are cheaper, the gear reduction might be too low. Replacing the motor, especially on an older Blue Box Athearn will cut the speed to a more prototypical speed and reduce the amp draw and will run smoother. There was a concern posted on possibly overloading the motors. I have a simple proceedure to determine maximum weight for the loco. The motors have a specified max amp. Place the engine on a level piece of track, say 3 ft. , tie a string to the coupler with a little slack. Now power up the engine and increase power slowly as the slack is taken out. When the string is taunt the engine will reach a point the just before the wheel spin is your max amp draw. Just add weight so that you don't exceed the max amp rating at this point. When the wheels spins you should see the amps remain below the max. Add or remove weight as needed. You can also put the rail on a 2% gradient (about a 3/4" spacer) and test again.

For me, the most challenging part of regearing on old brass steam engine is re-attaching the wheel that was removed from the axle so that the plane formed by this wheel is absolutely perpendicular to the axle and parallel to the plant formed by the other wheel. Re-quatering is never as much of a problem as this.

Any comments or suggestions?

I haven't really had much of a problem with this unless the driver was originally had a wobble. Before removing, scribe a mark with axle end and driver hub to get the driver near correct quarter when putting it back. Use a puller to remove the wheel and a small press to put it back on. By using a press you will generally get everything to go on correctly.

I have an old rubber band drive Athern GP7/9, painted and decaled shell
Any suggestions on how I can re-power it to a fly-wheel drive ?

Bob

CVSSDragonslayer wrote:I have an old rubber band drive Athern GP7/9, painted and decaled shell
Any suggestions on how I can re-power it to a fly-wheel drive ?

Bob

Pick up a new model with the new drive. You'll get better handrails, sideframes and the flywheel drive. You can find them cheap on ebay. If the one you have holds a special significance to you, simply swap the shells. You can always remove the guts from the one you have to make it a dummy. But, to answer your question, there's really no easy way. The mounts for the motor are different and the truck kingpins are different.