DCC Braking

[Gordon H]

Oh yes, DCC can do all of that, and more! - most of my diesels now have cab lights that auto fade to nil, when the loco moves off..

Can't do that in DC I'll bet?

 

Not that many would want to do it anyway, but if you had a DC loco with sufficient on-board storage to run a cab light in the first place it would be relatively trivial to construct an extra piece of circuitry to make it fade to off when the track voltage rises, so yes it could be done in DC.

Some years ago I was involved in producing a similar effect for an HO Dutch electric 1600 class loco, whereby its second pantograph would drop once the DC track voltage was raised above a certain level to simulate the real thing doing this once the train was in motion and drawing less current.

Edited December 23, 2015 by Gordon H

[Donw]

Interesting discussion. If you have driven a train, had a footplate ride when pulling a train or just paid attention as a passenger you would notice that full size the train does not stop quickly when power is shut off like our models. Typically the driver will coast in towards the station and slow down by brake applications, one quite a way out to bring the speed down, another before entering the platforms and a final one to stop fully. You can of course replicate this with a DC controller by careful use of the speed control but you need to minimise any momentum effect and you would need to practice with each loco as the control setting will vary  and it will not integrate with sound.

Interestingly back in 1962 Railway Modeller featured an article on building a transistor based controller basically an emitter follower design but by using multiple stages  the input  from the control potentiometer was a very low current and between that an the first amplification and different braking rates could be switched in as well as a coast setting and a slow rise to increasing the speed setting. It shows the concept is not new however the implementation is more sophisticated now with sound.

I wanted to add sound to my 0 gauge railmotor and have ordered a zimo decoder with immersive drive and railmotor sound files so I will see for myself.

My father in law had been in the slip coach off the Torbay express into Reading. He had thought there must be some power in the coach as it ran so freely with the guard adjusting the speed by judicious brake applications being careful nt to stop too early. No doubt a job for an experienced guard.

We may have to get expperienced in driving our models.

 

Don

[rogerzilla]

The newer Bachmann 6 pin decoders have a brake function in F2.  Set the deceleration rate to a really high value so the train coasts when you shut off power, then use F2 (make non-latching) to stop it.

 

 

[Hamburger]

A brake button has been available on all well-developed decoders for 10 (or more) years.

[RAF96]

Several decoders have a braking facility which modifies the CV4 value by a factor, hence when the allocated F key is pressed it applies this factor to CV4 providing the illusion of braking.

 

in a software application this can manifest by way of a separate throttle and brake slider. When the throttle is retarded nothing happens to the loco speed (coasting), until the brake slider is applied, which enables the throttle setting and applies a factor equivalent to the brake slider level. If the brake is released then the loco reverts to the speed set by the throttle, hence you can brake against the throttle to check speed for a signal or points crossing.

Edited January 18, 2020 by RAF96

[DaveArkley]

On 17/01/2020 at 19:26, rogerzilla said:

The newer Bachmann 6 pin decoders have a brake function in F2.  Set the deceleration rate to a really high value so the train coasts when you shut off power, then use F2 (make non-latching) to stop it.

 

 

That's becaused they are rebadged Zimo decoders.

 

Cheers

Dave

[NIK]

On 17/01/2020 at 22:13, Hamburger said:

A brake button has been available on all well-developed decoders for 10 (or more) years.

Hi,

 

Could you provide a list of decoders that have had a brake button over the last ten years?.

 

Regards

 

Nick

[Nigelcliffe]

24 minutes ago, NIK said:

 

Could you provide a list of decoders that have had a brake button over the last ten years?.

 

 

Soundtraxx for one.   I think that includes the motor-only MC1/MC2 which Bachmann UK were re-badging before they swapped to Zimo as a decoder source.

 

 

- Nigel

 

[Andy Reichert]

On 11/01/2020 at 01:14, Donw said:

Interesting discussion. If you have driven a train, had a footplate ride when pulling a train or just paid attention as a passenger you would notice that full size the train does not stop quickly when power is shut off like our models. Typically the driver will coast in towards the station and slow down by brake applications, one quite a way out to bring the speed down, another before entering the platforms and a final one to stop fully. You can of course replicate this with a DC controller by careful use of the speed control but you need to minimise any momentum effect and you would need to practice with each loco as the control setting will vary  and it will not integrate with sound.

Interestingly back in 1962 Railway Modeller featured an article on building a transistor based controller basically an emitter follower design but by using multiple stages  the input  from the control potentiometer was a very low current and between that an the first amplification and different braking rates could be switched in as well as a coast setting and a slow rise to increasing the speed setting. It shows the concept is not new however the implementation is more sophisticated now with sound.

I wanted to add sound to my 0 gauge railmotor and have ordered a zimo decoder with immersive drive and railmotor sound files so I will see for myself.

My father in law had been in the slip coach off the Torbay express into Reading. He had thought there must be some power in the coach as it ran so freely with the guard adjusting the speed by judicious brake applications being careful nt to stop too early. No doubt a job for an experienced guard.

We may have to get expperienced in driving our models.

 

Don

 

Been there, built that. Back then an OC28 cost a lot of money for a teenager. It worked as claimed, except for the "half wave" circuit, which didn't work at all for me. A decade later I deigned my own replacement with a bemf feedback drive system using op amps in an analog computing configuration to dynamically calculate the feedback values. 

 

Andy

[NIK]

6 minutes ago, Nigelcliffe said:

 

Soundtraxx for one.   I think that includes the motor-only MC1/MC2 which Bachmann UK were re-badging before they swapped to Zimo as a decoder source.

 

 

- Nigel

 

Hi Nigel,

 

I hadn't looked at Soundtraxx. It was a MC1 that Bachmann rebadged although the Bachmann website referenced the MC2 information.

 

 

Regards

 

Nick

[Ron Ron Ron]

4 hours ago, NIK said:

I hadn't looked at Soundtraxx. It was a MC1 that Bachmann rebadged although the Bachmann website referenced the MC2 information.

 

It was a hybrid made for Bachmann.

MC2 sized PCB

MC1 functionality

4 functions (MC1 = 2 function, MC2 = 4 function)

21-pin (not available on either the MC1 or MC2)

 

 

 

.

[Hamburger]

8 hours ago, NIK said:

Hi,

 

Could you provide a list of decoders that have had a brake button over the last ten years?.

 

Regards

 

Nick

Hi Nick,

 

it must have been in 2009 when I updated my Loksound 3 to version 3.5. 
With this update came a function called dynamic brake.

 

In fact it was possible to assign it to an F-key and it reduced the CV4 value by half and so I used it as a brake button. 

At this time nobody talked about or was even thinking about a brake button.
My model rail friends didnt even understand what I was doing. They always set CV4 low and did everything with the throttle.

Coming to a halt with full chuffing was not criticized, they didnt know better.

 

All this was refined with the Loksound 4, now you were able to adjust the CV4 reduction with CV 179.

 

Years before, Zimo had a similar function, but the reduction of CV4 was set to 25%.
Later it was also possible to adjust this value.

Interesting, you can update every ESU decoder since the V3 and almost all Zimo decoders to get this brake button.

 

One or two US suppliers also came out with a brake function around this time, I think it was first called dynamic brake, too.

Nobody talked about a brake button, but in fact it was there, just with a different name.

 

Zimo and ESU have developed their things further - Zimo with a progressive brake force feature (by P.C.?), ESU with 3 different brake settings which can be matched to different operational situations.

D&H is on the '2017 level' now, means they have a brake button with separately adjustable deceleration (for me that would be enough because progressive or multiple braking can get complicated in model railroading stress situations).

Interestingly they offer the feature to automatically (!) activate the brake function as soon as the throttle is set to zero.

Edited January 22, 2020 by Hamburger

[NIK]

6 hours ago, Hamburger said:

Hi Nick,

 

it must have been in 2009 when I updated my Loksound 3 to version 3.5. 
With this update came a function called dynamic brake.

 

In fact it was possible to assign it to an F-key and it reduced the CV4 value by half and so I used it as a brake button. 

At this time nobody talked about or was even thinking about a brake button.
My model rail friends didnt even understand what I was doing. They always set CV4 low and did everything with the throttle.

Coming to a halt with full chuffing was not criticized, they didnt know better.

 

All this was refined with the Loksound 4, now you were able to adjust the CV4 reduction with CV 179.

 

Years before, Zimo had a similar function, but the reduction of CV4 was set to 25%.
Later it was also possible to adjust this value.

Interesting, you can update every ESU decoder since the V3 and almost all Zimo decoders to get this brake button.

 

One or two US suppliers also came out with a brake function around this time, I think it was first called dynamic brake, too.

Nobody talked about a brake button, but in fact it was there, just with a different name.

 

Zimo and ESU have developed their things further - Zimo with a progressive brake force feature (by P.C.?), ESU with 3 different brake settings which can be matched to different operational situations.

D&H is on the '2017 level' now, means they have a brake button with separately adjustable deceleration (for me that would be enough because progressive or multiple braking can get complicated in model railroading stress situations).

Interestingly they offer the feature to automatically (!) activate the brake function as soon as the throttle is set to zero.

Hi,

 

Thanks for all that info.

 

Is the brake button widely available on non sound decoders?.

 

Regards

 

Nick

 

[Ray H]

One of our club member's was operating the O gauge layout last week and was complaining that the brake function wasn't working - he said the loco would accelerate when the brake key was released.

 

I was busy at the time and din't explore further but I did do a bit of investigation.

 

We use NCE throttles with the Horn/Whistle key set to invoke the "dynamic" - or whatever - brake function but only whilst that key is depressed. The F2 key still activates the brake but as a push on push off key effectively causes the decoder to work to the lowest applicable CV value i.e. stopping the loco reasonably quickly.

 

Most of our decoders are Zimos but we do have a few ESU decoders and the loco in question had an ESU decoder.

 

Many of the members don't appreciate or can't be bothered to use the Make While Pressed key and simply leave the F2 key "on" all the time. That works fine with Zimo decoders.

 

However, from what I read over the weekend, ESU decoder's brake function works differently. It works similar to the Zimo decoders if CV4's value is greater than that of CV179 and the press to make key is used. It appears to work completely differently if the Press On Press Off key is left On all the time.

 

It also appears that if CV179 has a greater value than CV4 the performance differs again depending on whether the brake is controlled by the Made whilst pressed key is used or the press on press off key is used.

 

I've probably not worded it very well but that's the way I understand it.

 

The South West Digital Latest News page explains it better than I have - look for the entry for December 2017.

[Hamburger]

5 hours ago, NIK said:

Hi,

 

Thanks for all that info.

 

Is the brake button widely available on non sound decoders?.

 

Regards

 

Nick

 

For Zimo and ESU yes.

I think on Zimo formerly it was 'hidden behind' the shunting mode function. Same for D&H.

[Hamburger]

1 hour ago, Ray H said:

One of our club member's was operating the O gauge layout last week and was complaining that the brake function wasn't working - he said the loco would accelerate when the brake key was released.

 

I was busy at the time and din't explore further but I did do a bit of investigation.

 

We use NCE throttles with the Horn/Whistle key set to invoke the "dynamic" - or whatever - brake function but only whilst that key is depressed. The F2 key still activates the brake but as a push on push off key effectively causes the decoder to work to the lowest applicable CV value i.e. stopping the loco reasonably quickly.

 

Most of our decoders are Zimos but we do have a few ESU decoders and the loco in question had an ESU decoder.

 

Many of the members don't appreciate or can't be bothered to use the Make While Pressed key and simply leave the F2 key "on" all the time. That works fine with Zimo decoders.

 

However, from what I read over the weekend, ESU decoder's brake function works differently. It works similar to the Zimo decoders if CV4's value is greater than that of CV179 and the press to make key is used. It appears to work completely differently if the Press On Press Off key is left On all the time.

 

It also appears that if CV179 has a greater value than CV4 the performance differs again depending on whether the brake is controlled by the Made whilst pressed key is used or the press on press off key is used.

 

I've probably not worded it very well but that's the way I understand it.

 

The South West Digital Latest News page explains it better than I have - look for the entry for December 2017.

Depends on whether you have V4 or V5.

 

On the V4, the value in CV 179 just replaces the value in CV4 as long as the function is active, thats all. Logically, the value in CV 179 must be smaller than CV 4. If you have the function on all the time, it is the same as permanently reducing CV4 .

 

On the V5 its more complex. CV 179 defines the brake force. The higher the value, the higher the brake force and the lower the brake distance.

So its vice versa to the V4.

 

And on V5 there is also CV 182 which defines whether the loco shall slow down automatically when the function is on, or whether it shall follow the throttle.

 

CV 182 defines the speed down to which automatic deceleration is to take place when the function is active.
A value of zero means that the locomotive brakes automatically to a standstill without you touching the throttle unless you switch the function off, and accelerates to the set speed after the function is switched off.
A value of 126 means that the locomotive only follows the throttle setting.

 

Maybe your problem is caused by value zero in CV 182`?

 

EDIT: same for 2nd and 3rd brake (forces are CVs 180 & 181, speed limit are CVs 183 & 184)

 

Edited January 22, 2020 by Hamburger

[RAF96]

I had a development copy of a DCC operating software to play with, written by a Train-Sim guy,  which had an optional throttle with a brake slider. This method let you cut the throttle without affecting loco speed, until you applied the brake slider. The retardation was proportional to the amount of brake applied. If some throttle was left on and the loco braked below this speed, when the brake was released it would resume that speed. Very realistic operation. This obviously modified CV4 relative to the amount of brake.

Edited January 22, 2020 by RAF96
Typos

[Ray H]

6 hours ago, Hamburger said:

Depends on whether you have V4 or V5.

 

On the V4, the value in CV 179 just replaces the value in CV4 as long as the function is active, thats all. Logically, the value in CV 179 must be smaller than CV 4. If you have the function on all the time, it is the same as permanently reducing CV4 .

 

On the V5 its more complex. CV 179 defines the brake force. The higher the value, the higher the brake force and the lower the brake distance.

So its vice versa to the V4.

 

And on V5 there is also CV 182 which defines whether the loco shall slow down automatically when the function is on, or whether it shall follow the throttle.

 

CV 182 defines the speed down to which automatic deceleration is to take place when the function is active.
A value of zero means that the locomotive brakes automatically to a standstill without you touching the throttle unless you switch the function off, and accelerates to the set speed after the function is switched off.
A value of 126 means that the locomotive only follows the throttle setting.

 

Maybe your problem is caused by value zero in CV 182`?

 

EDIT: same for 2nd and 3rd brake (forces are CVs 180 & 181, speed limit are CVs 183 & 184)

 

 

We've only got V4's. The Zimo's work with CV4 having the higher value but ESU give two different scenarios according to South West Digital's web site, with CV4 having both higher and lower values than CV179 and whether the brake function is on all the time or is On then Off then On . . . . 

 

At least that's the way I read it and it would tend to agree with the situation my colleague experienced last week.

[rogerzilla]

By default on my Bachmann decoders, the brake function seems to be disabled at high throttle settings but will stop a train at low throttle (regardless of actual speed).  Generally I'd cut the throttle to zero before braking but it certainly doesn't work the same as a Gaugemaster DS on DC...the brake will always overpower the throttle on a DS.