Good evening everyone, I am brand new to the hobby as well as the forum. I have a question that I am sure someone here can probably provide a decent answer to. I have just completed laying track for my first layout. I am using a Digitrax Zephyr DCC system, on a reasonable sized layout which contains a single main loop, a passing loop, and a 2 spur industry that fits on a 40" X 60" board. I am using an Atlas #48634 GP-40-2 Loco with a Digitrax DN163A0 decoder in it. My question is how fast should this engine run, when I first put it on the track it took 3 or 4 minutes for it to begin moving at all, now it seems to run fine at full speed, just not very fast and when I get it down near 1 on the controller it is really slow, anything below and there is no movement, it takes about 30 seconds to go around my main loop, just seems kind of slow to me, am I way wrong? Thanks in advance.
WELCOME. I’m into HO but in the meantime should you ever what to know speed calculations,
http:www.mcr5.org/articals/speed.htm
Slow is better[:D] Most model locos go too fast
Going slow when the Zephyr throttle at “1” is normal. I believe your Atlas has the slow scale speed motor which is a good improvement as it allows more precise slow speed control. You need to slow speed in the yards and coupling cars.
In one of my Atlas that has the slow motor I need a “2.25” or “2.5” on the Zephyr to get realistic running speed. This is in my eyes as I’ve never clocked it and do the math.
Also, do you have rolling stock hooked up to the loco? Without rolling stock, the loco appears to be running slower. It’s an illusion. Attach 5 or so cars and then see if it’s too slow. 
Hi Scanner,
Welcome to the world of Configuration Variables (CVs). The phenomena you describe are a function of CVs (the variable instructions that you program into your decoder), more than they are of your throttle or motor. You’ve got two CV’s at play here: CV03, which controls your acceleration rate to a pre-determined throttle setting, and CV05, which controls your maximum voltage, and hence your top speed. If your loco is sitting for 3 or 4 minutes before it starts to move, then you’ve probably got CV03 programed to way too high a value. On my Atlas GP18, I’ve programmed CV03 to a value of 5. Response isn’t instantaneous, but you don’t want it to be, but it is quick enough that you feel that you are actually controlling the locomotive. I agree with DSchmitt and mktrains: you don’t want your top speed too high, and what sometimes looks slow in N scale can be a pretty good speed in full size, so don’t program CV05 to too a high a value either.
Hope this helps.
Thank you the input has been great. I look forward to continued time in the forum.