Author Topic: Athearn Challenger slow operations  (Read 385 times)

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robertjohndavis

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Athearn Challenger slow operations
« on: December 08, 2024, 10:26:28 PM »
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Wise ones, I need your help.

My family has an Athearn Challenger from the 2018 era (Northern Pacific Z8). It has DCC and sound provided via a Tsunami board.

It’s always run slow. Too slow. I have mucked around with decoder settings but nothing works.

Wondering if anyone has had a similar experience? If so, was there a CV-setting solve? Or are we looking at motor replacement?

All the best,

Rob
« Last Edit: December 09, 2024, 09:08:04 PM by GaryHinshaw »

peteski

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Re: Athearn Challenger slow operations
« Reply #1 on: December 08, 2024, 11:07:44 PM »
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Athearn changed the motor in the more recent runs of Challengers and Big-Boys.  Not much you can do about that other than maybe try to find one of the earlier motors.  I have an early Big-Boy and my friend has a more recent release and the top speed difference is pretty dramatic.

Mine is from 2013.
« Last Edit: December 08, 2024, 11:13:47 PM by peteski »
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delamaize

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Re: Athearn Challenger slow operations
« Reply #2 on: December 09, 2024, 03:06:55 PM »
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Oh boy, the Z8....*sigh*
There was a fix from Athearn for the top speed, they were replacing motors for different, faster ones, I doubt that program is still going. I did probably 25-30 hours of work to mine modifying, amd fixing atherns mistakes.

Here is an excerpt from a thread back on 2018 about what I did.
Quote
So, It's pretty much a known thing, The Athearn Challenger is kinda a Lemon. It sucks because it is such a nice looking locomotive.

On to why I dug up this thread. I sent mine back to Athearns to be "fixed." It came back with a different motor, which improved the speed problem, Mine does about 60 SMHP now, I would prefer prototype top speed, but I'll take this over 30 SMPH, which is what mine did originally. Even after the "Repairs" that Athearn did, it still pulled like hot garbage.

So, It went on my work bench.....Off and on for over the last year or more.......

A few days ago, at the Train show, at Washington State History Museum, I did some test running on our club layout (MRNS). First test run was on the NTRAK Mountain line. First test resulted in a drastic improvement. Originally it struggled to pull 25 cars. Now, With my improvements, 40 cars from multiple manufactures. Needless to say, I'm pretty impressed with the improvement. Now, Yesterday, I had some time on the Inner Main. So why not? lets see what it will REALLY do. I started with 40 mixed freight cars, with 30, 40' box cars, Mostly MT, and 7 gondolas, (mostly MT) 3 flat cars, and a caboose. It pulled with no issues. I ran it like this for probably 30 minutes, then I decided to go after it. I started adding 5 more box cars every other lap. So, where is the top? Well that depends on what you call top. With no slippage at all, 50 cars is all it's got. I had 60 on it, But it would slip a lot in the corners. 55 was doable, but it did have some slight slip in the corners.

This is a drastic improvement, but it wasn't with out a LOT of work. so what did I do?

New traction tires, that are taller and slightly wider. This is creating a problem right now as the traction tire groove is not wide enough, so the traction tires are bowed up a little near the outside edge of the wheels, which makes it have a little bit of a bump when it runs. But it's not a big deal. I'm planning on chucking the wheels into a dremel or lathe and making the grooves slightly wider, one of these days.
But wait, Their is more.

I added weight in the boiler, and on top of both of the drive trucks.
Tweaked the lateral gear alignments, and made shims to try to help with gear walk.
re-quartered all the drivers.
Tweaked CV settings
De-lubed, and re-lubed everything
Cut one turn out of the spring on the pilot truck
Removed the spring and screw/pin on the rear truck.
Tweaked, and tuned valve gear
Gauged all the wheels
Adjusted, and tweaked electrical pickups
Rewired everything in the locomotive
Replaced all the wire in the locomotive.

Still to do:
Find places to add more weight
Dremel or lathe out the traction tire groove wider
re-engineer and rebuild the rear truck mount

Oh, I forgot about that, So, the rear truck.....
It is mounted, by a pivot at the front of the truck, attached to the rear of the power truck, then a screw/pin to the bottom of the firebox, with a spring for tension. So, here is the problem, The pivot on the front of the truck is too low, which lifts the front of the truck off the rails. When you push down on the rear truck, to put the front axle on the rail head. It lifts the front of the power truck off the rails by like 1/4". In addition, it only allows for lateral swing, No vertical movement at all. I am working on fixing this right now. I'm hoping this might squeak out a few more cars, some how.

Stay Tuned for more, I will try to make updates as I make changes, and post the results.

It has been a ton of investigation and work to get to this point, IMHO way too much work for a brand new locomotive. But, It is a beautiful looking locomotive, and it does run well, But you'd think  Manufacture would put a little more testing and proving on designs, especially when the prototype was known for pulling 100 loaded boxcars, at 100 MPH across the plains.
From this topic: https://www.therailwire.net/forum/index.php?topic=42939.75

Another good topic, this one has a few videos of my Challenger pulling 50 cars.
https://www.therailwire.net/forum/index.php?topic=55499.0

Yet another topic on the Challenger
https://www.therailwire.net/forum/index.php?topic=43629.0
 It's a gorgeous locomotive, but a poor performer unless you're willing to do a lot of work, some pretty risky.
Mike

Northern Pacific, Tacoma Division, 4th subdivision "The Prarie Line" (still in planning stages)

robertjohndavis

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Re: Athearn Challenger slow operations
« Reply #3 on: December 09, 2024, 08:39:19 PM »
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@delamaize thank you so much for taking the time to direct me to your prior content. My search missed those posts. They explain so much. Now to figure how much money and risk I wish to take. I great appreciate all the detail you have shared. - Rob