SPEED MATCHING

[sonnyw]

DOES ANYBODY KNOWHOW TO SPEED MATCH A REGULAR BACHMANN DCC EQUIPPED DIESEL ENGINE TO A DCC SOUND EQUIPPED DIESEL BACHMANN ENGINE?

[jward]

do you have dcc readback capabilities? if so, here's how I would do it.

the basic Bachmann dcc onboard locomotive decoder may not support cv5 and cv6. those are your max and mid voltage settings. you can assume the sound equipped locomotive decoder supports those cvs, so you will need to adjust its cvs.

first step, do a readback of both cv5 and cv6. write down these values as you'll need them later.

step two, run the dcc locomotive around a loop of track, and time it with a stopwatch. do this both at full throttle, and at half throttle.

step 3 repeat step 2 with the sound equipped locomotive.

step 4, divide the observed time for the dcc onboard locomotive by the time of the sound locomotive, using both top speed times. multiply the resulting number by the value of cv 5 in the sound locomotive, and reprogram the new value into cv5.

step 5  repeat step 4 for the mid range speeds, and reprogram into cv6.

your locomotives should now run close to the same speed.

note that cv5 has a max value of 255. if your sound locomotive is the slower of the two and cv5 is 255, you won't be able to adjust the top speed to match the dcc onboard locomotive, but you will still be able to adjust the mid range speed.  in this case, consider replacing the decoder of the dcc onboard locomotive with one which supports cv5 and cv6.

[sonnyw]

thanks jeff,ill try that.sw

[DAVE2744]

Jeff - Do you think your suggested method would work for the well geared down B'mann Shay and a Rivarossi Heisler? I run these engines at scale speeds, Shay top at 10 mph, Heisler at 15 mph.  I know these two are fighting each other, the Heisler winning out due to it's heavy cast boiler & cab.  Dave

[jward]

I don't see any reason it wouldn't work for those as well.