Independent Head and Taillight Operation

[PaulK]

Hi All,

Do any of you know how to separate the headlight from the taillight operation (normally on function 0)? 

 

It's so annoying that when a loco is attached to a train that the taillights are showing. This, of course, is totally un-prototypical. 

 

I would be grateful for the benefit of your knowledge.

 

Thanks.

Paul

[Andymsa]

If the decoder interface is 8 pins the only way is to modify the pcb board in the loco. If a plux/ Mtc interface you can change this in the function outputs.

 

its not particularly hard to change the pcb board 

Edited March 16, 2019 by Andymsa

[Art Dent]

Hi,

 

As Andy has already said, the only way to switch off the red tail lights when the loco is at the head of a train in virtually all R-T-R locos is to modify the circuit board or install your own lighting assembly (or commercial one from, say, Express Models) and have them connected to different function outputs - e.g. F0 for the No.1 end headlight/headcode box, F3 for the No.2 end rear lights, etc.

 

The only R-T-R model(s) that I know have independent switching of the rear lights are the Sutton Locomotive Works Class 24s  (<< Link) which has a PluX22 interface.

 

There are probably others, but I only know of the above.

 

Hope this helps,

 

Art

Edited March 16, 2019 by Art Dent

[newbryford]

39 minutes ago, Art Dent said:

Hi,

 

As Andy has already said, the only way to switch off the red tail lights when the loco is at the head of a train in virtually all R-T-R locos is to modify the circuit board or install your own lighting assembly (or commercial one from, say, Express Models) and have them connected to different function outputs - e.g. F0 for the No.1 end headlight/headcode box, F3 for the No.2 end rear lights, etc.

 

The only R-T-R model(s) that I know have independent switching of the rear lights are the Sutton Locomotive Works Class 24s  (<< Link) which has a PluX22 interface.

 

There are probably others, but I only know of the above.

 

Hope this helps,

 

Art

 

Dapol Class 68 has switchable tail lights.

The forthcoming Hattons 66 is specified as having them also.

 

 

[peterfgf]

There are some good ideas on this website which I came across when chipping my Hornby Class 50:

 

http://s374444733.websitehome.co.uk/class-50/index.htm

 

Peterfgf

[PaulK]

Hi All,

Thank you for your thoughts. So annoying that really great models have this totally un-realistic problem.

 

Come on manufacturers head and tail lights as a different function and we can all get it right!

 

Cheers.

 

Paul

[RedgateModels]

I have an article with BRM waiting for publication with this very conversion done to a 21 pin Bachmann class 37, also switchable and directional cab lighting too!

 

Basically you need to isolate the tail lights from the pcb (they are switched on the Bachmann so easy to do) then connect them to two spare functions on the decoder and map up a spare F button (i used F20) to turn them on and off ...

 

@Howard Smith might be able to give an idea of when it will surface?

[Pete the Elaner]

On 16/03/2019 at 19:22, newbryford said:

 

Dapol Class 68 has switchable tail lights.

The forthcoming Hattons 66 is specified as having them also.

 

 

The staff member I spoke to at MR Scotland confirmed this.

The standard of models is ever increasing. I hope this sets a new standard.

 

As Richard pointed out, the downside of this is that the more switchable functions there are, the more decoders will need to provide. This is ok with a sound decoder but non-sound ones typically have only 4 function outputs.

[RedgateModels]

7 minutes ago, Richard Croft said:

Most decoders don't have enough function outputs to operate them. Having the reds and white separated uses 4 function outputs, then if it has cab lights you will need another function output, or 2 if you separate them to be directional

 

agreed, thankfully the Zimo sound decoder had plenty  

 

I used functions 1 and 2 for the cab lights and 3 and 4 for the tail lights. Headlights left on Function 0 as standard.

[PaulK]

Surely you would only need two functions if you left the lights as directionally controlled and just the function to turn them on or off?

 

Cheers.

Paul

[RedgateModels]

1 minute ago, PaulK said:

Surely you would only need two functions if you left the lights as directionally controlled and just the function to turn them on or off?

 

Cheers.

Paul

 

You may be confusing decoder function outputs with handset F keys. Easily done and I make great efforts in my article to differentiate between the two. 

 

On a standard decoder you have forward and reverse lighting (white and yellow wire) on F0 which confuses things as the decoder outputs (white and yellow wire) are commonly referred to as F0f and F0r . Each decoder manufacturer tends to come up with their own notification however. In any case you have two wires coming out of the the decoder to work the forward and reverse lighting, all controlled with a single F key (F0) on the handset.

 

To have separate tail lights you need another two wires from the decoder to connect to each end of the loco's red lights and then map up these wires to a spare handset F key. 

[PaulK]

Ah, I think!

 

Cheers.

Paul

[RedgateModels]

Lenz documentation helps in this matter (for once) by calling their function outputs A, B, C, D etc so there is little confusion with the handset F button numbers

 

White wire is output A

Yellow wire is output B

Green wire is output C

etc

 

Shame all decoder manufacturers have not followed their example

[RedgateModels]

Just now, PaulK said:

Ah, I think!

 

Cheers.

Paul

 

Don't worry, it's one of those things that once you get it the light bulb comes on

[RedgateModels]

Hopefully this will not confuse you more, but take a look at the table below - this is standard NMRA function mapping. The yellow shaded settings should be defaults

 

 

 

 

Look at the first two rows, they are F0 on your handset. by having a value of 1 in cv33 connects the white wire to F0 going forward. a value of 2 in cv34 connects F0 to the yellow wire going backwards.

 

All the remaining function outputs (green, purple wires etc) work in both directions, so to get what you want you need something like a Zimo decoder that allows you to change this using cvs 125 to 160 to modify the behaviour of the function outputs. I won't go into this too much though as it is decoder specific.

 

Confused?

Edited July 29, 2022 by RedgateModels
lost image removed

[RedgateModels]

I guess this is why manufacturers don't offer this as standard, as even if they wired the tail lights separately not only would you have to buy a four function decoder to make them work you would also have to get something like a Zimo and mess around with CVs to get them to work seamlessly ....

 

Most ppl would not be happy with having to press F1 to turn on the #2 end tail light and remember to not only turn it off when changing direction but also to press F2 to turn on the #1 end one

 

Guess why I like Zimo decoders

[Bucoops]

How do you "manage" multiple front lights such as the 4 markers on diesels etc. I know on the LLC Class 15 they programmed multiple configurations - how many outputs would that need?

[pauliebanger]

The LLC Class 15 uses 9 Function Outputs (A ZIMO decoder, of course).

 

4 for each individual marker at the front and another 4 for each individual marker at the rear.

The 9th FO is used for the cab light.

 

Those are the individual hardware connections I designed into the lighting circuit at the outset. Without them, it would be impossible to control each individual LED.

 

The extremely flexible ZIMO Swiss Mapping then allows anyone to set any number of lamps/arrays to single or multiple F keys with a few CV changes. But, this can only work if the individual LEDs are physically separately wired to the decoder. This was achieved by using a very comprehesively designed PCB. Literally, every pin-out form the decoder either terminates on the PCB in a JSP socket or has an individual solder pad for external connection.

 

That's what's possible (and very easily and cheaply achieved) if such considerations are included at the design stage.

 

Unfortunately, many 00 and N gauge models still suffer from being fitted with 'just enough' outputs for the model to work 'as supplied'. The end user who wishes to enhance the features provided then has to fend for themselves. You will find that this is changing as Bachmann and Graham Farish introduce new designs of DCC and DCC ready models.

 

EG, The GF Class 40 has a lighting scheme in which the rear lamps can be switched off (manually on DC) with a Function Key on DCC. Although they are equipped with ZIMO decoders (see any pattern emerging?) the model has its own independent way (modified PCB components) of achieving this.

 

BTW, whilst on the issue of powering Tail Lamps, I assume its widely understood that in the past normally only one lamp would be illuminated even if the loco was fitted with a pair. (Changed in more recent years).

 

In order to achieve this (with a choice of which one of each pair should be illuminated) requires an additional 2 FOs to the numbers given in earlier posts, i.e. 6 for just markers and tails, 7 or 8 if you add cab lights/direction dependent individual cab lights plus a further 2 for any additional lights at either end. These things soon add up if you require full independent control.

 

 

Best regards,

 

Paul

 

 

Edited March 20, 2019 by pauliebanger

[Bucoops]

Thank you Paul, recognised your name with being involved straight away.

 

The decoders I am looking at have 4 outputs so stumps me on that.

[shady]

With at least some 4 funtion decoders it is possible to have directional front lights (ie headlight and marker lights) directional tail lights and directional cab interior lights. You have to except the limitation that the tail lights and or the interior cab lights can only be switched on when the front lights are on, but thats acceptable to me. I know this works as I did a test install in a Lima 50 , from memory it worked with lenz standard and the hattons cheap decoders. I suppose you could sacrifice the interior cab light and have a choice between left or right side tail light, but l would need to dig out my diagrams to confirm that.

 

Unfortunately I am currently living in temp rented accomodation and all my model railway and electronics stuff is in boxes in a mates loft so not easily accesable. I am certain l still have a test set up on a breadboard in a box , within a box in a loft.

 

Shady

[pauliebanger]

1 hour ago, shady said:

With at least some 4 funtion decoders it is possible to have directional front lights (ie headlight and marker lights) directional tail lights and directional cab interior lights. You have to except the limitation that the tail lights and or the interior cab lights can only be switched on when the front lights are on, but thats acceptable to me. I know this works as I did a test install in a Lima 50 , from memory it worked with lenz standard and the hattons cheap decoders. I suppose you could sacrifice the interior cab light and have a choice between left or right side tail light, but l would need to dig out my diagrams to confirm that.

 

Unfortunately I am currently living in temp rented accomodation and all my model railway and electronics stuff is in boxes in a mates loft so not easily accesable. I am certain l still have a test set up on a breadboard in a box , within a box in a loft.

 

Shady

 

Other things are possible if you are prepared to add circuitry Even a TTS decoder with only 3 FOs can be persuaded to operate markers and tails independently at each end (normally requiring 4 FOs if relying on the decoder alone) but you need to add a PNP transistor and a couple of extra resistors. See my feature in Hornby Magazine issue 96, TTS Class 40.

 

Best regards,

 

Paul

[RedgateModels]

Thanks for contributing Paul, and for helping me with the article

[Howard Smith]

On 20/03/2019 at 13:41, RedgateModels said:

I have an article with BRM waiting for publication with this very conversion done to a 21 pin Bachmann class 37, also switchable and directional cab lighting too!

 

@Howard Smith might be able to give an idea of when it will surface?

 

That'll be the September issue...

[RedgateModels]

Should be quite an issue for DCC users so I am told

[Graham Radish]

My class 70 farish has a switch at the bottom, i rewired this to switch off all lighting at one end, and fitted the buffer detailing pack to just one end, thus meaning its all correct in running. connect the bottom switch to the blue (commom +) on one side of the loco, job done.

Edited March 23, 2019 by Graham Radish