DCC questions and insite

[dlind]

I have two Bachmann DCC locos: 1 purchased w/ DCC and the other I upgraded to DCC.  They are both SD40-2s.  Is it common for the 2 locomotives to run at two different speeds even though the controller is indicating they are both running at the same speed?  I have them both set up for 128 speed steps.  I am using a MRC  Prodigy Express DCC controller.  One loco can be set to 50 (native DCC loco) and the other (upgraded DCC loco) to 50 and the native DCC loco will catch up to the upgraded engine in about 10 laps around the track.  Any suggestions?

Also, where can I find a list of all the Bachmann supported DCC CV#s and what each one of them do?

Thanks

[the Bach-man]

Dear dlind,
If one loco is significantly older it is possible that they will run at different speeds.
For decoder info, Click on the EZ Command button at left,
Have fun!
the Bach-man

[dlind]

Bach-man,

Both locos were purchased in the last 6 months.  Also, the native DCC loco is quite a bit louder than the loco that was DCC upgraded.  Is it possible that I have a drive train issue on the upgraded loco?

[Yampa Bob]

It's difficult to troubleshoot when you have 2 separate issues, in other words, is the problem mechanical or the decoders?

Power your track with DC, and run both locos.  Incidentally, I always run any new DCC loco on DC until it is thoroughly broken in and well matched to similar units.  Some take longer to break in than others. 

The difference in "loudness" could be merely a lubrication problem, or a roughness in the castings.  You didn't say what size your layout is, but if it takes 10 laps for one loco to catch the other, I would say the 2 are pretty well matched in speed.  With identical locos, motors and drive system the same, the slightest binding or lack of lubrication can create the difference.  Bottom line, get them matched as close as possible on DC first.

Only then can you concentrate on the decoders, which may be slightly different. If you have to set one to "50" and the other to say "60",  well, isn't that the purpose of being able to change CVs?  If all locomotives ran exactly the same, then you wouldn't need the capability. 

Good luck

[Jim Banner]

Depending on what decoder you installed, you may be able to match speeds using a three point match or a speed table match.  But if it takes 10 laps to catch up on a normal sized layout, they should be close enough as is.  Lubrication may or may not help, but at six months, it won't hurt. 

You might have a drive train problem, possibly tight gears, but with speeds that close, I would suspect the noise is more likely coming from the shell.  Sometimes a shell will resonate with a small, normal vibration and amplify it.  Other times, vibration will be coupled to the shell, for example by a decoder or a bird's nest of wires that touches both the mechanism and the shell.  Perhaps a further look at the mechanics of your decoder installation is in order.  This, by the way, is a good reason for making sure a locomotive runs well on dc before upgrading it to DCC.  Unfortunately, it's a "must do" that we all too often "just don't."  More than once I have had to restore a locomotive to dc operation to do what I should have done in the first place.

[dlind]

Thank you for the all the info.  I guess I am used to having to have things perfectly matched for my job that it has carried on to railroading.  I will try to play with CVs to try and tweak the locos. 

[Yampa Bob]

Tweaking is fun as long as it doesn't become an obsession.  I often run 2 or 3 diesel locomotives in consist, even with opposite orientations, on DC power.  I don't worry about slight speed differences, I just sit back and enjoy the experience.

[pdlethbridge]

When I worked in the bindery, there was one guy who was constantly readjusting things on his machine rather than give it a wait and see approach. 'Mr. fix-it had poor production because he was always trying to fix what was really not broken. So, "don't fix what ain't broke".

[dlind]

Mr. Bach-man,

How many road #'s are available for the BN SD40-2 series locos?  I have 7845 and 7849 currently and am looking at getting a couple more.

Thanks

[the Bach-man]

Dear dlind,
I believe those are the only numbers currently available, with new numbers applied to the next run.
Have fun!
the Bach-man

[Linzthom]

The problem with the 2 locos is quite simple. The eletric motor.  The electric motors in model locos are not made to a super fine tolerance so the slight variations in manufacture will mean they won't run at exactly the same revs. as each other given the same elecrical input .

I have 3 Rivarossi Heislers and they are  all running at differant speeds with the same input. Sorry, it's a fact of life.