New GP7

[oldford]

I just bought a new GP7 at the train show in Springfield, MA an I like the artwork and the detail, but I'm having a bit of trouble with it.  Compared to my other engines, the response is slow and a bit sluggish, even after about 30 minutes of run time.  Another thing, when I hit the stop button on my throttle the engine seems to stop suddenly as if it hits a wall.  This is completely different from my Kato or Atlas engines.  This is the only Bachmann that I have, so I don't have a point of reference.  It almost seems as if there is something binding, but I don't seem to be able to pin it down.....  Any thoughts???

Frank

[ACY]

It has DCC, but I don't think it has flywheels, so that explains the slow response (takes more voltage to start) and the sudden stops.

[skipgear]

As mentioned above, it doesn't have flywheels so it is not going to coast when you remove power suddenly. It is DCC so it requires a little more voltage to get it going than a DC loco. It's not clear if you are using DCC or not. As far as the overall speed, these are geared correctly unlike Kato and early Atlas loco's. These loco's top out at a reasonable scale speed, not mach 5 like the others, especially the Kato's. On DC, the momentum programmed in DCC is still in effect so no matter how fast you ramp up the throttle, it will accellerate slowly. This can be changed if you have DCC or access to a DCC system by programing CV3 and CV4 to 0. This will eliminate the momentum completely.

[oldford]

Yes, I am running DCC.  I'm relatively new to trains in general, not just DCC.  It just seems that, compared to the Kato and Atlas, this engine requires much more start-up power and then dies immediately.  All  engines are DCC.  I have set the acceleration and deceleration values when I programmed the engines to 1.  I assume that means I set the steps to 1 unit of acceleration rather than a larger multiple units. (If you follow...)  Perhaps if I set the values for this engine differently than the Kato.  Maybe I'll try it.

Frank

[skipgear]

The best settings I found were:

CV02 = 0  (Start Voltage)
CV03 = 3  (Accel rate)
CV04 = 3  (Decel rate)

I am amazed how slow this loco will run. It makes it great for switching. The speed range for the GP is about where I think loco's should be. If you want it to change speed more slowly, increase CV03 and 04. Play around with it and see what works for you. Unfortunately this decoder doesn't have a Vmax (CV05) so you can't change the top speed voltage. You should be able to do that with the decoders in your Atlas and Kato loco's to match their speed to the GP and make them perform more similar.

[jake_iv]

The Atlas GP7 made in China was made by Sanda Kan, Bachmann (Kader Industries) acquired Sanda Kan in late 2008.  The Bachmann GP7 is the next step in the developement of N scale motive power.  Back when (mid-60's) almost all N scale had 3 pole low power, high speed motors acceptable for "toys" in Europe and the far east.  Available locos were about evenly split between "pancake motors and more traditional permag motors.  The next step was 5 pole motors, some companies went out of business before the change was made; next was flywheels - to smooth out the start and help locos make it over switches and crossings with gaps that were sometimes longer than the loco wheelbase.  Next came the skew wound motors which smoothed out start speed and speed changes further.  The top of the line today is the coreless motor with bell shaped armature - extremely smooth startup and speed transitions.  DCC advances control even further by allowing you to preset the start voltage to just barely stopped and max voltage to the actual scale mph of the prototype.  Your older Atlas GP7s made by either Kato of Sanda Kan had top speeds of over 200 smph.  Unfortunately, most of us have gotten used to these totally unrealistic speeds over the past years and think something must be "wrong" when a loco actually performs prototypically.

MOMENTUM:  DCC momentum settings are actually an electronically timed speed change up or down.  The original standards call for a setting of 0 to 30 - this figure represents the number of seconds it takes the loco to reach full speed or full stop.  Since your new Bachmann GP7 has a more realistic top speed  adjusting momentum on this loco wil result in a totally different speed curve than on the Kato or Sanda Kan engines.  For example - if you set accel to the max of 30 it will take 30 seconds  for the new Bachmann to reach a scale 75 or 80 mph - while comparatively the Kato or SK will take 30 seconds to reach over 200 smph.

STOP BUTTON - the stop button on your controller is a "Panic Stop".  It is there to save you from a disaster.  It is not intended to be used to stop your loco under normal conditions.  Recommended DCC standards call for it to cut off all electrical feed to the system immediately!  If you have flywheel equipped locos the residual motion of the flywheel systems prevents an immediate stop.  You will really appreciate no flywheels and that panic button the first time someone diverts your attention from your trains so that you have only a couple of seconds before slamming into the rear of your new articulated loco with sound

As you get accustomed to the realistic operation of your new Bachmann locos you will find yourself setting up a sales table at the next area swap meet or opening a eBay account.

Just as a point of interest - looking through a 1950 Railroad Model Craftsman mag last nite I came across the news item that the average speeds of freight trains in the US had increased since the end of WWII - The American Association of Railroads reported that the average freight train speed had RISEN to almost 22 mph.  My 1960's edition Rapido FA starts faster than that!

[oldford]

Can anyone tell me where to get the programming manual for this engine?  I have tried to find it on Bachmann's web site, but if it is there, it's well hidden.  If I knew who's decoder it is, I might start there.  I'm really not happy with this loco.  It seems to take forever to get started, then once moving, suddenly leaps forward at a break-neck speed.  I tried the values below:
CV02 = 0  (Start Voltage)
CV03 = 3  (Accel rate)
CV04 = 3  (Decel rate)

but I'm still not happy.  If I had a manual, there might be suggested ranges for the values of each of the CV's. 

Frank

[ACY]

Can anyone tell me where to get the programming manual for this engine?  I have tried to find it on Bachmann's web site, but if it is there, it's well hidden.  If I knew who's decoder it is, I might start there.  I'm really not happy with this loco.  It seems to take forever to get started, then once moving, suddenly leaps forward at a break-neck speed.  I tried the values below:
CV02 = 0  (Start Voltage)
CV03 = 3  (Accel rate)
CV04 = 3  (Decel rate)
but I'm still not happy.  If I had a manual, there might be suggested ranges for the values of each of the CV's. 

There are no manuals that provide suggested values for your decoder, you will just have to experiment with different values until you are satisfied. The decoder is made by Lenz for Bachmann. All that is available is an exploded parts diagram for the locomotive and a little pamphlet that states the factory settings for the CVs. Your exploded diagram should be in the box with the loco unless you threw it out. Here is the only reference for your decoder, be aware it offers no advice as to what values are ideal: http://www.bachmanntrains.com/home-usa/ez_content/1_Amp_Decoder_Instr.pdf

[skipgear]

Try setting the CV3 and 4 = 0. Then there will be no momentum delay and your hand at the throttle will be the only thing controling the rate of acceleration.

What DCC system are you running it with by the way?

[oldford]

I'm using MRC Advance.  I set the values to the suggested ones in the EZ Command leaflet.  Seems to be a bit better. I'll try the value of 0 in the two CV's.  For the difference in price between the Atlas, Kato and Bachmann, I don't know why anyone would buy this Bachmann.  Why do they hide the information from the consumer?  There is more, in my mind, to customer satisfaction besides paint schemes.  Very disappointed. I know my experience with programming decoders is limited, but the Atlas and Kato engines have to deal with the same operator - me.

Frank

[skipgear]

Are you on 28  or 128 speed step on your Advance? If I remember correctly, even though not noted, the GP7 decoder will work on 128 speed step and that should greatly improve your throttle control. Another thing you can try is work with the start voltage value (CV2).

What I like to do to fine tune the settings on a loco is set it on the main at speed step 1. Enter programming in OPPs mode so that you can program on the main. If you are not sure how your system works, then pull the other loco's off the main just in case you hit a wrong button and reset the programing on them. Then I will program CV2, starting at 0 and then increasing 1 at a time till I find a speed I am happy with at speed step one. Some loco's do need a bit of a start up boost.

You may just have a bad loco also. I have seen on of the 44T's that acted somewhat like that. Turned out to be a cold solder joint on one of the components on the decoder board.

I have a friend who is in the total opposite situation a you. He has now bought 8 of the the Bachmann GP's because he is getting fed up with his Atlas stuff. This is a gentleman with a large.... no huge, basement layout that he is running operations on. He can't stand it when stuff doesn't work and in the past week he has lost two Atlas factory decoders, had to "adjust" the contacts on 3 more, and replace a split drive cup on another. He is prepared to set the Atlas loco's on a siding as background scenery.

These are all new loco's by the way. The layout has been in process for 6 years and in the past week or so he finally has it ready for operations. He has been getting out the fleet that he has accumulated and testing them for duty on the track.  After his frustration with the Atlas loco's, he said he may come in to the shop and order 8 more GP's so that the guys running on his layout can have something reliable to use.