I want to speed match two locomotives to run in a consist.
First I’ll tell you what I’m using for locomotives. I have two matched Athearn Blue Box SD40-2 frames with matched Mashima motors and Cary cast metal E7 A&B bodies. I also have two Model Power E7 frames with matched Canon EN22D motors and Hobbytown of Boston cast metal E7 A&B shells. I do not want to speed match the Atherans with the Model Powers just Athearn to Athearn and Model Power to Model Power.
Second how close does the speed of two locomotive have to be for maximum efficiency when running in a consist?
All four locomotives have MRC 1730 DCC decoders and I’m using JMRI Decoder Pro for programming. The MRC 1730 decoder is a MRC 1716 but doesn’t include the speaker.
I usually set up one locomotive as the ‘master’ then match the other locomotives to that one. I do this by running them side by side on a straight section of track. Like in a staging area or yard. ( in my consist, all the locomotives have the same address as they are permanent.) I try accelerating and braking and constant speeds. I have found that as long as they are close, they run fine together. Two of my consist are 5 locomotives long.
I guess I have both pairs matched OK, I have a 99 foot double loop that has a 3½% grade in one leg and if I separate the locomotives by about 18” and run them as a consist after completing the 99’ they’re within a couple of inches from the starting point. The motors were purchased in pairs together and when I run them on DC they are also vary close. The only CV I changed is the Start Volts from 10 to 12 in the two Model Power Canon EN22Ds, I didn’t have to change any other CVs to match speed, all four decoders are at factory default in the Motor, Basic Speed Control and Speed Table.
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
Close is good enough. They don’t have to be in absolutely perfect lockstep, especially unloaded. Hook them together and add a train behind, and the pulling evens out a lot. You just don;t want one spinning away and the other not even starting to move.
The Athearns do better with the Mashima motors than the Model Power with the Canon EN22Ds. The Athearns don’t slow down when they hit my 3½% grade but the Model Power with the Canon motors slow down just a bit when they hit the grade. As I mentioned above all decoders are programmed the same with the exception of the start voltage on the Canons, the Canons were a bit sluggish on start so I upped them a bit.
All four E7s have good power and speed so with your help I’m over that problem. I wasn’t going to use sound decoders in my diesels but after hearing the EMD 567 sound I changed my mind.
I then have a small script which allows me to record what the scale speed is based on what speed step. This requires multiple passes by the same loco at different throttle settings. (After adjusting for start voltage) I then use this as a calibration table.