I have a MTH GP-7 2014 vol 1 catalog. Is your GP-7 slow/weak? Compared to all other engines that I have it just doesn't fly around the track like the others.
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Ed,
What engines are you comparing it to?
This engine has speed control which holds some voltage in reserve for when more is needed to maintain speed. It will always run at a lower speed for a given voltage as compared to an engine without speed control.
Jim
Recent legacy gp35 sd70 sd80mac and MTH Alco Rs-1 2012 Not running DCS just a z controller think 1000. I turn the knob to full blast and this gp-7 just putts along. Others are flying.
Thanks for responding.
Ed,
I would think that it should be comparable to your MTH RS1.
Some possiblities you or your repair tech might want to explore:
A mechanical binding in the gears.
One motor running slow.
Tach reader out of correct position in its mount.
Tach tape problem - loose, smeared, or otherwise not readable.
Marty F. or Gunrunner John might have some other or better ideas, too.
Jim
Turn off Odyssey and see if that changes anything.
It's an MTH engine, so there's no Odyssey to turn off. However, MTH does have a speed limiter feature to keep kids from running the engines too fast. I forget how it works but it should be in the manual under conventional operation. It can get turned on accidentally; I did have one engine come out of the box with the limiter engaged. I ran into this when I was trying to sell it. I went to demo it and it just crawled along the track. Lost the sale, but I finally found in the manual how to turn it off. This was with PS/2 but I assume PS/3 has the same feature.
Originally Posted by gunrunnerjohn:
Turn off Odyssey and see if that changes anything.
Ed,
Turning the MTH speed control off, as John said, is a good idea to try (even if it isn't called Odyssey 
)
Here's how to do it in conventional for a Proto-2 engine:
To turn speed control on and off, put the engine in neutral, then press the transformer’s Whistle button one time then immediately press the Bell button two times. Two horn blasts will indicate that the engine has made the change. Repeat the 1 whistle, 2 bells code to return it to the other condition. You will want to do this during the initial neutral upon start-up if you ever couple this engine to another engine that is not equipped with speed control to avoid damaging the motors in either engine. Each time you shut down the engine completely, it will automatically turn speed control on.
Jim
Wrong speed control, but Jim rescued me.
I forget how it works
The speed limit is a DCS-only feature that's actually set in an individual DCS Remote, rather than in the engine itself. It has no bearing whatsoever on your situation.
Yes, Barry is correct. Lionel's TMCC, and I presume Legacy, have a speed-limiting feature
for the kids and madmen (not Mad Men...Don), also.
I don't play with them often. I'm familiar with Lionel/odyssey/tmcc. Train doesn't stop as quickly with odyssey off I believe. The whistle/bell suggestion worked. now it takes off. Thanks for the help.
Your symptoms sounded like cruise control "reserve", so it makes sense disabling it helped the top end. I rarely test the top end of my locomotives, so this question really doesn't come up for me. 
Ed,
Glad to hear that turning off the speed control worked out for you.
Happy railroading,
Jim
