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Offline einotuominen  
#1 Posted : 07 February 2023 13:26:18(UTC)
einotuominen

Finland   
Joined: 19/09/2022(UTC)
Posts: 378
Location: Kaarina
Hi guys,

this is very Rocrail specific. Brakes squeal perfectly when driving manually, so that is not an issue here.

But in Rocrail automatic mode. There is a feature called BBT (Block Brake Timer) that gradually decelerates loco between a block enter and in sensors. It is a great feature as it will after a few attempts learn how to slow down the loco so that it will look smooth and stop with precision.

But with it goes away the brake squealing.

With BBT the velocity will be set to 0 eventually, but it is not a sharp curve as the loco has been decelerating already for several seconds.

Has any one got a proper solution for this? Installing a speaker inside station building and playing sound files through that is not in my opinion a very nice solution.

I know that JohnjeanB is driving automation with mSD3 locos, have you got any experience? Love

Best regards,
-Eino
Offline PMPeter  
#2 Posted : 07 February 2023 16:33:53(UTC)
PMPeter

Canada   
Joined: 04/04/2013(UTC)
Posts: 1,273
Location: Port Moody, BC
I use Rocrail and BBT and I have no issue with the brake squeal. In my case it doesn't happen when the loco enters the block and the BBT kicks in, but the squeal starts when it is in the final step of deceleration and hits the In sensor. It works for all of my locos.
Offline einotuominen  
#3 Posted : 07 February 2023 16:37:03(UTC)
einotuominen

Finland   
Joined: 19/09/2022(UTC)
Posts: 378
Location: Kaarina
Originally Posted by: PMPeter Go to Quoted Post
I use Rocrail and BBT and I have no issue with the brake squeal. In my case it doesn't happen when the loco enters the block and the BBT kicks in, but the squeal starts when it is in the final step of deceleration and hits the In sensor. It works for all of my locos.


Have you made any changes to the decoder thresholds?

I don’t get the squeal at the In event when velocity goes to 0.

However squeal happens on non BBT blocks if loco is to stop in the block.

Strange…

-Eino
Offline PMPeter  
#4 Posted : 07 February 2023 17:47:22(UTC)
PMPeter

Canada   
Joined: 04/04/2013(UTC)
Posts: 1,273
Location: Port Moody, BC
No I made no changes to the decoder. I get the squeal in BBT blocks on the In event and in non BBT blocks if the loco has to stop due to an occupied next block. I am using a CS2.
thanks 1 user liked this useful post by PMPeter
Offline PeFu  
#5 Posted : 07 February 2023 18:24:50(UTC)
PeFu

Sweden   
Joined: 30/08/2002(UTC)
Posts: 1,208
I have experienced similar features on some decoders. You could try changing the ”Threshold for brake squealing” of the decoder (CV64), using a value of 1-255:

The higher the value the sooner the squealing begins, the lower the value the later the squealing begins. If
the value is too low, no squealing is activated.


(From the mSD3 manual.)
Andreasburg-Mattiasberg Bahn is inspired by Swiss railways |Forum Thread |Track Plan |Youtube | C and K track | CS2 | TrainController Gold V10
thanks 1 user liked this useful post by PeFu
Offline Martti Mäntylä  
#6 Posted : 07 February 2023 18:29:08(UTC)
Martti Mäntylä

Finland   
Joined: 15/11/2018(UTC)
Posts: 397
Location: Uusimaa, Helsinki
Set decoder deceleration to take place faster and/or from higher V_min and the squealing should emerge at some point.

This comes with the loss of some control, as Rocrail cannot stop the loco precisely at the sensor any longer.

Edit: PeFu beat me in replying. His suggestion may help too, but I have no experience on this approach.
- Martti M.
Era III analog & digital (Rocrail, CAN Digital Bahn, Gleisbox/MS2, K83/K84), C & M tracks, some Spur 1
Offline einotuominen  
#7 Posted : 07 February 2023 18:51:54(UTC)
einotuominen

Finland   
Joined: 19/09/2022(UTC)
Posts: 378
Location: Kaarina
All right! Great suggestions. I'll try out both of them together and separately.

Thanks!

-Eino
Offline JohnjeanB  
#8 Posted : 07 February 2023 22:57:43(UTC)
JohnjeanB

France   
Joined: 04/02/2011(UTC)
Posts: 3,084
Location: Paris, France
Hi Eino
Originally Posted by: einotuominen Go to Quoted Post
Hi guys,

this is very Rocrail specific. Brakes squeal perfectly when driving manually, so that is not an issue here.

But in Rocrail automatic mode. There is a feature called BBT (Block Brake Timer) that gradually decelerates loco between a block enter and in sensors. It is a great feature as it will after a few attempts learn how to slow down the loco so that it will look smooth and stop with precision.

But with it goes away the brake squealing.

With BBT the velocity will be set to 0 eventually, but it is not a sharp curve as the loco has been decelerating already for several seconds.

Has any one got a proper solution for this? Installing a speaker inside station building and playing sound files through that is not in my opinion a very nice solution.

I know that JohnjeanB is driving automation with mSD3 locos, have you got any experience? Love

Best regards,
-Eino

The only thing Rocrail does differently compared to manual control is multiple digital orders to change the speed so the Squealing Sound (SS) may be affected

Speed generally used by Rocrail
- V_max: normally not used
- V_ cruise: speed used when between blocks
- V_med: speed when approching a closed (red) signal
- V_min: speed used in detailed blocks, on staging blocks, on turn table

Note: the above speeds are defined specifically for each loco and block speeds or route speeds can be different in percentage of the max speed the loco in the block or route.

Things not done by Rocrail (done by the loco decoder)
- inertia (called acceleration delay , braking delay)
- braking squeals parameters: minimum speed to reach before the sound started, the speed level when the squealing sound is triggered, and many others (See below)
- braking squealing inhibition
- maximum speed (as defined in the CS3 and CS2) and may be used to reduce the maximum speed to a realistic value. (so ROCRAIL's Max speed difinition is CASCADED with the CS3 Maximum speed (e.g.: CS3 Max speed is 90% and RR Max speed is 80% then RR resulting max speed will be that of 0.80x .090) of the locos absolute max speed.

Sorry for these long preliminary notes.

So, to be clear, Rocrail does not do ANYTHING to inhibit squealing BUT, the succession of speed change order may prevent the squealing sound to be heard.
So the parameters on Märklin recent decoders (mSD3 and mSD2) I know (there may be more) are

- CV 164 "Bandbreite Bremsschwelle (bandwidth speed threshold. It )is the duration (time) of the brake squeaking. The higher the value, the earlier this noise starts when stopping (value in 0.1 seconds) Recommended value=5

- CV 163 "Korrecture Auslauf".(Correction factor progress) allows to correct the start of SS when too early or too late. Recommended value is 2

- CV 64 "Bremsenquietschen Schwelle" (0 - 255). This is a SS threashold.The squeaking begins, the larger the value, the earlier, the smaller the value, the later. If the value is too small, no squeaking is triggered. Important note: this treshold is to decide IF the SS will be triggered and not AT WHAT SPEED. See it as a condition.

Sorry the subject is not easy to digest but:
- consider adjusting the SS parameters on the MFX decoder
- strangely it will work better when having strong speed variations

Cheers
Jean






Offline einotuominen  
#9 Posted : 11 February 2023 10:54:40(UTC)
einotuominen

Finland   
Joined: 19/09/2022(UTC)
Posts: 378
Location: Kaarina
Thank you guys, I’ll start experimenting and get back to this topic if and when I find proper settings.

-Eino
thanks 1 user liked this useful post by einotuominen
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