Hi all, when I try double heading, the two motors are not in sync and either one is pushing or pulling the other. Any advice you can offer how to ensure smooth running without causing damage to the motors?

I ran different which probably makes it more challenging. But even with identical locos do you need to tweak or fone tune to make it work?

I know CS3 can set up MU, but I don't think it manages the synchronization unless I miss something here. Could you elaborate and guide me how to sync the locos?

That sets up MU, but it doesn't automatically sync the motor characteristics. My question was if both motors have different acceleration or deceleration delays, different max speed, etc. then they will have different pulling force. Even when I set the same values for both motors, it may still not work.

No, you have to manually tune the two locos yourself. Depending on the decoders in them this could be difficult. I wouldn't want to be trying to match an mLD/3 or mSD/3 decoder to an fx decoder for example.

Not being familiar with the latest Märklin decoders or the CS, I also intend to run trains as double headers and I've done this successfully but as it turns out there is a lot of programming to be done., yes one can set all the CV's to same value but this doesn't automatically make the locos run the same speed, I still have to jiggle with the speed of 1 loco to get it right.
I usually de-activate the acceleration so the 2 locos don't battle it out for, who is pulling or pushing but they still have to run at the same speed
My other problem however is running 2 locos electrically together (electric couplings) is when they enter a braking section and you find 1 slider or pantograph is within the braking section and the other outside of the braking section causing a short., the reason behind it was to get a greater electrical contact for both locos so any dead spot on the track wouldn't effect either loco, the only other way is using electrical couplings but 1 loco hasn't got an electrical contact with the track but rather with the other loco, in the end it could be messy when you uncouple the loco with the electrical coupling and couple it to a freight car with metal coupling and this happened to me.

here is a video from a double headed loco but even more risky 1 puller and 1 pusher with a very long freight train

I tune my engines that I can run MU's such as Re 10/10's like those on the SBB. I set up a test track to calibrate the delay parameters, top speed and then change the motor speed curve to linear. It is also possible to do this with the old 6090 decoders but it is more fiddly. Top speed is calibrated by timing the how long it takes for the loco to complete one circuit of the test track. As long as you can set the top speed and speed curve to match the locs will run well together in my experience.

Regards,
Roger

Listen to me very carefully, I shall say this only once......(as was said by a famous Frenchwoman)

No, No, No, No, No, No, No! Mamma Mia....! (to quote another famous person)

This implies that there is a continual feedback from the loco decoder to the controller / software on motor performance. I know the msD3 decoders perform an automatic calibration to the motor being used when first run, but that is internal to the decoder, it isn't feed back to the controller. I don't know of any such system that does that!

As others have said, you have to calibrate each loco to match each other yourself. I get two parallel tracks, put both locos on, set the same speed for each and let them go. If one is faster than the other then it gets adjusted until you have a match. You will never get them perfect, there will be instances during coming up to speed that one loco will push/pull the other. Some of that can be adjusted with speed curves and acceleration delay but they are never perfect. It's the same whether the locos are H0 or Gauge 1.

So, in summary there is NO automatic adjustments by controllers to match two locos, the controllers have no way to assess the performance of each loco...

That sounds like the software is relying on sensors within the track and it measuring the time a loco takes to travel between two sensor points, which I guess could be used to achieve the desired outcome. But I don't know of any system that works on direct speed control data from a loco decoder to a controller, and calibration adjustments made on the fly from that.

kiwiAlan, the Train Controller I was referring to is RR&Co Train Controller.
I my case the software uses three adjacent occupancy feedbacks to perform the calibration. The software runs the engine back and forth at different speeds. It is not done on the fly.
I just wanted say that you, in most cases, can use a software instead of fiddling with Cvs.

Hi

Definitely, the CS3 or CS2 is not synchronizing the locos in a double or triple header.
Yes it is easier with very similar locos but a good multiple header is possible with recent MFX decoders (with adjustable speed curve, acceleration & braking delay) no matter the loco type (gear ratio, etc).
To adjust you need to
- set both decoders with the same curve type (e.g.: standard exponential)
- set both locos on a long stretch of line and separated by 20 cm and test different speeds. If one loco is faster reduce its maximum speed parameter
- set both acceleration delay to same value and check as previously and adjust the fastest starting one
- repeat the process for breaking delay.
Now you may couple both locos and have fantastic results
Cheers
Jean

Hi Not sure what you mean
Jean

Hi,

Roger hit the nail on the head - see his post #13 above.
I'll share my tips with you too.

Firstly, I am using CS2, and all locos in the videos below have 60760 decoders.
Yes, it doesn't have to be smart expensive decoders, it can work with the 60760 kit as well.
I am using my good old trusty 6021 Controller to set the CV values of the 60760 decoders because the CS2 for some reason doesn't set them properly.

Here are two videos of my E94 and BR24 locos running together.

Marklin Double Head E94

Marklin Double Head BR24


Step 1 :
I always run all of my locos at speed setting 60 on the speed dial on the CS2 speed controller.
And the max on the dial on the CS2 speed controller is 120. (you can set this on the CS2 settings screen, and note that this does not adjust the decoder)
So from the Train Driver perspective, the locos are all running at 60kph which is half of their speed setting of 120kph.

Furthermore, I have created a Memory Event for locos to all 'Go' on the layout at their speed setting of 60,
and also another Memory Event for all locos to 'Stop' on the layout, both of these by means of a single Memory Event click.
So its easy to reset the position every time when you are programming your locos just by clicking a Memory Event click.
And, importantly, the locos always run at the same speed setting which is set in the Memory Event button.

Step 2
Put the 2 locos which you want to double head separately on the track, one some distance in front of the other.
Click the Memory Event to run them at the standard speed of 60.
Watch the two locos go around the track, and watch which loco goes faster, and which one goes slower.

Step 3
For the loco which you want to adjust the speed, go to your programming track and change the Maximum Speed CV value speed setting.
For most decoders, this is CV05.
Simply put, if you are running at 60 and your Maximum Speed is 120, then you are running at half-speed.
If you are running at 60 and your Maximum Speed is set to 90, then you are running at 2/3rd speed.
So, adjust the CV05 in the one loco little bit by little bit, and repeat the exercise, until you get the 2 locos to run at exactly the same speed on the layout.

Step 4
Now similarly adjust the Accelerating and Braking Delays CV03 on the decoder using your programming track until the acceleration and braking of the two locos looks similar.

Step 5
Put the locos together on the track, click the Memory Event button, and watch them gloriously ride together.

Regards
John

Found a short explainer video from Maerklin for a double traction. Is in German but with subtitles.