Most of the new N gauge locos have scale speed motors in them so they won't do 100 MPH on one quarter throttle. CV 2 is used to adjust the starting speed and I agree that breaking in a loco by running for a time in both directions before programming speed CV's. Also before setting CV 2 you should set CV 3 and 4 (acceleration and deceleration) rates to 0. Some decoders do not support adjusting CV's 5 and 6 (middle and top speed). Read that decoders spec sheet.
I would break them in for a couple hours before making any adjustments. I'm always amazed at how performance improves after a loco has been run in for a few hours. Atlas locos are pretty good quality. They may just be a little tight when new.
All locos are different, that's why decoders have CVs to adjust motor characteristics, like CV2 for the start voltage. It would also help to know what decoder is in each of these, and if either of them has back EMF control. If not BEMF, they often will had other motor adjustments, some manufacturers call it "dither". Between these adjustments, you should be able to make any loco run at near creeping speed on speed step 1 on the throttle.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
The decoder's "Start Voltage" (CV 2) needs to be adjusted. Program a value of 24 to start into CV 2 and see if it starts at a lower throttle setting. You should be able to get it to the point that it will start moving on Speed Step 1 by increasing the value in CV 2.
Bought a couple of locos (I'm just starting out), N Scale. One Diesel from Atlas and one Steam from Bachman. Both DCC. Put them on my test track and at 1% throttle the Steam Engine starts running (albeit very slowly), good news. Tried the Atlas Diesel and I had to advance the throttle to 405 to get the loco moving. I'm running Digitrax but I had the engine tried on an NEC system as well, same result. I was at the store when they tried NEC. So, we tried a few other engines and all the Atlas ones (we tried 3 or 4), required that 40% setting to get moving. We then tried another Bachman (small pusher) and it started within 5%.
So, is this normal? Is there something that needs to be done to the Atlas Engines or is that just the way they are?
Thanks - Don Martin.