Hello All,
How important is gearing in a DCC locomotive when making up consists?
The reason I‘m asking is when running consists in analog (D/C) having locomotives of the same gearing was paramount in smooth operation. To the point of when making consists of ,2, 3 and even 4 loco consists I would MU locos of the same model and manufacturer to the extent of the the same origin of manufacturing to insure the same gearing. Which lead to many of my consists to have all the same road numbers- -not very prototypical to say the least. But on a mountain pike like mine synchronicity was more important than appearance.
Now with the advent of digitally assigned acceleration curves or steps is the gearing of the individual loco as vital if all acceleration curves are set to the same values?
Also, assuming all acceleration curves are equal does anyone see problems with consisting the same locomotive type; GP-40’s for example from different manufacturers- - Atlas, Athearn & Bachmann?
Thank you all in advance for your input.
J.J.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
While gearing helps in consists, with the DCC decoders you just change the speed tables a little bit here and there so that the locos aren't fighting with one another.
So, with four locos (1,2,3,and 4), all you need to do is get the first one programmed to where you want it -- e.g. "top speed = 60 sMPH", and then write down the config values that give smooth steps from 1 sMPH to 60 sMPH across all the speed steps (e.g. start speed (vMin) = 1, Mid speed (vMid)= 90, top speed (vMax)= 200).
Now, loco 2 ... start with 1/90/200, and see if it tops out at 60 sMPH. If it does, then run locos 1 and 2 together for a couple loops, checking that one's not pulling/pushing the other at various speeds. If not, then the locomotives are speed matched. If there are some problems, then alter vMid / vMax on loco 2 until it's smoothed out.
Repeat this with locos 3 and 4, testing them against loco 1. Since 1 & 2 are speed matched, there's no reason to test locos 3 & 4 against it (or each other).
What this might mean is that you have speed tables in each individual locomotive that look like this
-Dan
Builder of Bowser steam! Railimages Site
Since you can't make a loco go faster than it's full speed so start with the slowest loco as your base unit. You can always slow down a DCC loco with speed tables and other means.
Richard
Geared the same, they will be easier to spped match - but like DC, there's no requirement in DCC for the locos to riun 100% in lock step - you CAN tune them that way, but it's a lot of effort for little gain. They should be CLOSE.
If the gearing does not match (or even if it does, but they have different motors), then you can take advantage of several options in decoders to match them up.
At start, one will probably start faster or need more throttle than the other to move. You can't slow down the faster one (assuming the mechanism is broken in, properly lubed, aligned, etc..) but you can speed up the slower one. Most of the time, just using the basic 3 step configuration works, unless using a decoder (like Tsunami) that doesn;t support CV6 for mid speed. So use CV2 to adjust the slower one up to match the faster one.
At full throttle, one will be faster than the other. You can;t speed up the slower one, but you can slow down the faster one. Adjust CV5 on the faster one to slow it down to match the slower one.
Now set the throttle to mid speed and adjust CV6 on either one, either speed up the slower one, or slow down the faster one. They now should be reasonably close across the throttle range.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Here is a link that explains how to speed match locos in DCC. It might seem complicated at first, but by the 2nd or 3rd loco that you do, it will be super easy and second nature.
Thank you all for the input.
I’m upgrading my digital (DCC) system so I can set CV values. This will all come in handy.
Again, thank you for your thoughts.