Loco Surging Question

[haasmarc]

Yeah, surging/hesitating is a better description.

Well, last night I remembered that I had an Intermountain SD40-2 so I dug it out this morning.  The trucks are different.  The new truck has a frame piece glued in that connects the side frames.  It is a pain in the butt because you can't take the truck apart for cleaning without it popping off and now that it isn't glued, it falls off all the time.  Best to just leave it off.

Anyway, I tried the trucks from the SD40-2 and it runs much better.  The gear clicking is gone.  The gear noise is about 85% reduced and most importantly the wheels keep spinning.  While not smooth as glass, I would say performance was increased 70%-80%.

I then checked my second unit and it had similar issues on both ends.  Swapping in the SD40-2 trucks had the same improvement for that unit as well.

I am definitely leaning towards the redesigned truck not being quite right.

Now to check with Intermountain to see if I can get some replacement trucks.  I needed to contact them anyway because one of my units is missing one of the plastic clips that holds the mechanism together.

[randgust]

I had that surging thing on my first attempt to put a TCS decoder in a Kato 11-105 chassis.   Did a warranty return, a second warranty return, sent it to WM Lee, he confirmed it and couldn't fix it either, finally scrapped the decoder out and put in a DZ126T and those have worked great.  TCS tried and failed to resolve it.   So it's not your imagination.  Mine was only at slow speed, but truly aggravating when you're doing a geared steam build.    Never seen it on another decoder since, between Digitrax, BLI, Tsunami.

I'm assuming you've confirmed that you can disconnect the decoder and jumper it around to test it on regular DC and it's not the motor.

I've also noticed a BIG difference in performance in speed control between my original Digitrax old school Zephyr power station and the new wireless throttles.  Those are much finer and more stable control ranges. 

[peteski]

Yes, TCS decoders (Z2) had issues (I experienced that myself), but according to the problem description they were not the ones mentioned.

[haasmarc]

Intermountain got back to me and are sending me some of the older style trucks.

I have always gotten good customer service from them.

[u18b]

Yes, TCS decoders (Z2) had issues (I experienced that myself), but according to the problem description they were not the ones mentioned.

Same for me too.

[NtheBasement]

On the chance that some tiny piece of grit is causing it, put the trucks in a jar of isopropyl and shake it.  If anything visible comes out that might be the issue.  I've solved a similar problem this way.

[jjb62556]

I also ended replacing some of the trucks with Atlas ones. It looked to me that some of the gears were not meshing being a little too narrow and would slip by each other making the clicking sound. Older Atlas ones did not for whatever reason. I buy the trucks whenever I find them...Jim