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I purchased a K-Line K29212 set at a swap meet yesterday - this is a Rio Grande Alco PA A-B-A set. All 3 units have smoke and both A units are powered with dual motors. A series of 8-pin connectors links the B unit and trailing A unit to the lead where the R2LC, DCDR, and RS boards reside. So the B unit and trailing A unit are "slaved" to the lead A unit.

This set runs pretty smoothly once it gets going, but the powered units jerk around some (possibly starting and stopping separately at different times) and the set struggles to start moving - I basically have to hit speed 3 on my CAB-2 to get them started and then dial it back so they're not rocketing around the rails. Sounds, smoke, and couplers all work fine and respond to commands from CAB-2, so I suspect this behavior is lack of cruise control and an aging/weak DCDR. However I'm curious if this is a symptom of the wiring setup as well - long connection from lead A unit, through B unit, to trailing A unit for motor control?

Has anyone installed a Cruise Commander M in a set like this? Any issues with a single CC-M driving 4 motors? Any issues with the long wiring connection from lead A unit to trailing A unit? I'd love to hear about some success stories or gotchas others have encountered doing an upgrade like this.

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Bottom line is, if you install a Cruise Commander M in this unit, you'll want to tether the bridge rectifier and heatsink it to allow for the additional load of the extra motors.  Other than that, it should be fairly smooth sailing.

Thanks for the summary @gunrunnerjohn. I read through the linked thread as well. There were some comments in the thread about heat sinking the rectifier directly to the frame - seems like this would require removing that part from the CC-M board and connecting it back via some wires so it can be mounted to the frame regardless of where exactly the CC-M needs to be located. Am I understanding this right and is this what you're referring to when you say "tether the bridge rectifier and heatsink it"?

If anyone has some pictures or more details about how this should be done, please share. I want to make sure I understand what needs to be done before I start down this path. Thanks!

@Norton posted:

K-Line took chances. Plus a DCDR is rated for 8 amps vs 6 amps for a Cruise M. Stall current for four motors is just over ten amps. I guess K-Line thought a DCDR could survive short term locked wheels. Truthfully how many times have you seen two diesels with all 4 trucks locked up?

Pete

Interesting - thanks for this additional info. This set does seem to need to "ramp up" to get moving, even after I greased up all the visible gears. But these are currently the only DC motored locos I have without Legacy cruise control or CC-M, so I'm struggling to recall how a vanilla DCDR behaves in a command environment. Perhaps the reason these locos lurch some and don't start moving until ~RR speed 2 is b/c the DCDR has degraded over time due to not being heatsinked properly? I'm hoping upgrading to a CC-M will eliminate this behavior and allow this set to crawl and run at low speeds like it has done for other locos (i.e. my TMCC Amtrak Dash-9).

I'll upload a video of them starting up to demonstrate what I mean

A DCDR has no Cruise capability. It runs the the engine the same as if you were using transformer handles in conventional its just you do it with a red dial vs a handle. Unplug you Legacy base and run the engine in conventional and you will see see it behaves the same. A Cruise M will perform like Legacy with half the speed steps.

Pete

I wasn't expecting DCDR to have cruise but want to better understand if this extremely lurchy starting behavior is:

  1. expected from a non-cruise DCDR in command environment
  2. not expected but due to wear of the DCDR itself

I think the answer is #1 but it's been forever since I've run a non-cruise DC locomotive and I don't recall if this is typical behavior or not. I expect a CC-M (properly heatsinked) should eliminate this even when driving all 4 motors?

Here's a video of a start to demonstrate what I mean.

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I installed a tethered CC-M (thanks @gunrunnerjohn). However that didn't resolve the lurches. After some more investigation, it looks like the lurchy starting/low-speed behavior is not due to the DCDR or lack of cruise, but due to motor binding. The rear motor/truck on the lead A-unit is binding at a regular interval and one or both are binding on the trailing A-unit as well. My focus has been on the lead A-unit since I can test it without the B-unit or trailing A-unit. I've taken the rear truck off the lead A-unit about a dozen times now and also tried swapping it with the rear truck from the trailing A-unit. I've done my best to get all the grease and gunk I can access off both the worm gear on the motor and the gear box, then added fresh grease (Labelle 106) to both. I've also tried adjusting the tightness of the screws connecting the motor mount to the truck. Nothing has helped to resolve the binding. Am I looking in the wrong place here? Any thoughts?

IMG_0018IMG_0020

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Last edited by Mike0289

Does the problem follow the motor or the truck? Looking at the truck, you can see bare metal where the worm seems to be making contact with the truck below the worm gear indicating maybe the worm is not on the motor shaft all the way. If thats the case rather than trying to push the gear on further, maybe grind a bit off the end with a dremel.

Pete

Thanks for the feedback, gents! The problem does seem to follow the motor, at least to some extent. Swapping rear trucks with the trailing A-unit may have helped some, but binding is still occurring. I'm hesitant to do anything destructive like taking a Dremel to the worm gear, but I think shimming the motor up a little bit should accomplish the same thing so I'll try that.

@Mike0289 posted:

Thanks for the feedback, gents! The problem does seem to follow the motor, at least to some extent. Swapping rear trucks with the trailing A-unit may have helped some, but binding is still occurring. I'm hesitant to do anything destructive like taking a Dremel to the worm gear, but I think shimming the motor up a little bit should accomplish the same thing so I'll try that.

Mike, take out a good motor and compare how far the motor worm extends beyond the mount to the one that touches the truck. Shimming the motor would work too.

Pete

That's a pretty rare occurrence, at least in my experience.  Of all the things I've had apart, I've only had one of the vertical motors with the steel worm had a crack.  I've seen plenty of cracked plastic gears, and even a couple of metal truck gears split, but the worm is pretty robust.

I meant worm gear, not worm. I.e. the gear that is driven by the worm.  They are often bronze or whatever and I’ve seen a few crack.  When they do, binding at a regular interval like the OP described is the symptom.

However, if the binding follows the motor, then it’s probably not a cracked worm gear.

After shimming the motor with some small, thin washers I had laying around, I'm happy to report that the lead A-unit is now running buttery smooth, even at speed step 1 (out of 100)! The issue apparently was that the worm was rubbing against the bottom of the gear box. Thanks to all for helping me get this far!

I think the worm gear in one of the trucks on the trailing A-unit has a crack in it - see attached image. Even after shimming the motor with the same type of washers, binding still occurs. The interval between binds is also quite a bit longer than it was for the motor/truck on the lead A-unit. This leads me to think it may in fact be the cracked worm gear that's the issue for this one. Out of curiosity, I checked a truck on the B-unit to see if they had the worm gear, but they do not.

Any idea where I could get a new worm gear for this set? And how hard is it to pull apart the truck and replace that gear?

97483F42-CADC-4412-8012-52B01FDADE06

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Last edited by Mike0289

Do you see a crack in the worm gear? Its not visible in the picture. With the motor installed, if the gear was cracked you should feel it binding every wheel revolution when you turn the flywheel by hand. Also look closely at the spur gears on the side. Any bit of debris in any of the gears will do the same thing. That is actually far more common than have a bronze gear crack,

Pete

Last edited by Norton

Sorry, forgot to attach the image of the cracked gear in the trailing A-unit truck! I’ve edited that post to add it.

@Norton posted:

Do you see a crack in the worm gear? Its not visible in the picture. With the motor installed, if the gear was cracked you should feel it binding every wheel revolution when you turn the flywheel by hand. Also look closely at the spur gears on the side. Any bit of debris in any of the gears will do the same thing. That is actually far more common than have a bronze gear crack,

Pete

I think there is a crack - see the image I attached to my previous post. I do feel it binding at a regular interval with the motor installed.

@PRR1950 posted:

I assume the picture for the trailing A-unit truck is different from the first set of truck and motor pictures.  For some reason, the trailing A-unit truck picture doesn't appear in the first post that references its existence?  I sure would like to follow along with this analysis.

Chuck

Image is attached now! Sorry for the confusion

@Norton posted:

Mike have you ruled out a metal chip in the spur gears. FWIW my K-Line E8 had a truck locking up until I cleared the chip. It doesn’t take much, smaller than a pin head will do this.

Pete

Last time I checked, the drive wheels will turn indefinitely (no binding) without the motor installed. I will take another look at this, though.

@Mike0289 posted:

Any idea if this is the part I’d need?

K2410-X002 Drive Gear Worm Wheel Shaft and Bearings Assy RS Pa Etc

https://traindoctor.com/service/kline/kline.php

There are a number of worm gear assemblies listed and I have no idea which one (if any) would be correct for this set. Is there a part breakdown available somewhere?

Looks like you found the problem. I would call Brasseurs to verify. They likely have the parts and service manuals.

Pete

@Mike0289 posted:

Last time I checked, the drive wheels will turn indefinitely (no binding) without the motor installed. I will take another look at this, though.

Still the case, so I think this means we can rule out any binding in the truck itself.

@Norton posted:

Looks like you found the problem. I would call Brasseurs to verify. They likely have the parts and service manuals.

Pete

Thanks Pete. I'll send them an email and see what comes back. Hopefully they can point me to the right part number and they have some in stock! I will follow up when I hear back

@Mike0289 posted:

I think the worm gear in one of the trucks on the trailing A-unit has a crack in it - see attached image.

Definitely cracked.

Any idea where I could get a new worm gear for this set? And how hard is it to pull apart the truck and replace that gear?

If the truck has screws to allow you to remove the wheel set, it shouldn’t be too difficult as the cracked gear can often just be pushed off after removing one wheel with a wheel puller.  Make a mark across the axle and wheel so you can re-align them later.

Putting a new gear on is a little trickier.  I think the right way is to use a press, but I’ve used a vice and a socket to do it, being careful to aline any splines and press slowly ensuring the gear stays perpendicular to the axle.  

If there is no way to remove the wheel set in one piece its a bit harder.  It might be easier to replace the whole truck.

@Mike0289 posted:

After shimming the motor with some small, thin washers I had laying around, I'm happy to report that the lead A-unit is now running buttery smooth, even at speed step 1 (out of 100)! The issue apparently was that the worm was rubbing against the bottom of the gear box. Thanks to all for helping me get this far!

I think the worm gear in one of the trucks on the trailing A-unit has a crack in it - see attached image. Even after shimming the motor with the same type of washers, binding still occurs. The interval between binds is also quite a bit longer than it was for the motor/truck on the lead A-unit. This leads me to think it may in fact be the cracked worm gear that's the issue for this one. Out of curiosity, I checked a truck on the B-unit to see if they had the worm gear, but they do not.

Any idea where I could get a new worm gear for this set? And how hard is it to pull apart the truck and replace that gear?

97483F42-CADC-4412-8012-52B01FDADE06

Degrease that thing to have a better looksie,…..might be cracked, but hard to tell amongst all that gooey stuff in the teeth,.…..a lot easier to work on/diagnose when it’s clean…..

Pat

@harmonyards posted:

Degrease that thing to have a better looksie,…..might be cracked, but hard to tell amongst all that gooey stuff in the teeth,.…..a lot easier to work on/diagnose when it’s clean…..

Pat

What do you recommend for this kind of cleaning? It's my first time doing this, so I'm not sure how to move forward cleaning the truck safely and effectively.

@Mike0289 posted:

What do you recommend for this kind of cleaning? It's my first time doing this, so I'm not sure how to move forward cleaning the truck safely and effectively.

A simple home solution, remove any plastic parts that you can. Use a small bucket with either purple power or simple green, and a little hot water, scrub with an old tooth brush ( not your wife’s or this thread is dead) ……..rinse in as hot water as you can stand. Blow dry if you have access to compressed air, or borrow your wife’s hair dryer, and blow dry as you rotate the wheels,…keep drying till all the water has evaporated off,….now you’ll have a nice clean part to better examine and work on,…..

Pat

@harmonyards posted:

A simple home solution, remove any plastic parts that you can. Use a small bucket with either purple power or simple green, and a little hot water, scrub with an old tooth brush ( not your wife’s or this thread is dead) ……..rinse in as hot water as you can stand. Blow dry if you have access to compressed air, or borrow your wife’s hair dryer, and blow dry as you rotate the wheels,…keep drying till all the water has evaporated off,….now you’ll have a nice clean part to better examine and work on,…..

Pat

Awesome, thanks for sharing this knowledge! I'll see if I can get that truck cleaned up and get a better picture of the gear.

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