Wiring protocol for DCC

[PMW]

I understand the point being made about forwards and backwards, but what is forward when there is no front or back to a locomotive, simply two identical driving cabs?

[Nigelcliffe]

1 minute ago, PMW said:

I understand the point being made about forwards and backwards, but what is forward when there is no front or back to a locomotive, simply two identical driving cabs?

 

They are very rarely "identical" perhaps they are similar, perhaps you haven't got your eye-in on the differences.   In nearly all cases, the grills on the body/roof will be a give-away once you're familiar with how they are arranged. 

 

- Nigel

[Andymsa]

9 minutes ago, PMW said:

I understand the point being made about forwards and backwards, but what is forward when there is no front or back to a locomotive, simply two identical driving cabs?

all my identical ended locos are numbered 1 and 2 at each end

[Nigelcliffe]

24 minutes ago, john new said:

 

NCE Powercab

 

I am stumped on offering alternatives.  The PowerCab is pretty sensible, there is a "direction" key to change direction, and the display says "Fwd / Rev".   Nothing on it indicating "left" or "right". 

 

 

 

 

[Crosland]

3 hours ago, john new said:

 

Therefore it does matter, as I said, which way round the traction unit is placed on the track as to which direction it moves in, relative to the layout, when you apply power. That is the fundamental flaw of DCC, 

 

It's not a flaw. The traction unit will always go forwards regardless of which way you place it on the track.

 

You seem to have attached a different meaning to "forwards".

[Crosland]

2 hours ago, john new said:

This is getting silly. On my layout from the usual viewing point if I add a DC loco chimney first pointing at the station it will go forwards/left+, with DCC turn it around and as you state it therefore goes right/for forwards and away from the station.

 

But it's still going forwards!!!

 

2 hours ago, john new said:

How is that not relating the direction it goes to the way you put the loco onto the track? 

 

Obviously the direction a loco faces determines what is forward and what is reverse.

 

You have to decouple your notion of left v. right from forward v. reverse. The direction in DCC is always relative to the loco you are driving, not the layout.

 

[Crosland]

47 minutes ago, PMW said:

I understand the point being made about forwards and backwards, but what is forward when there is no front or back to a locomotive, simply two identical driving cabs?

 

If you fit directional lighting then you can determine the direction it will move off from the lights, unless you have a ZTC command station (unless that bug has been fixed). They should change as soon as you change the direction, even at speed zero.

[john new]

51 minutes ago, Crosland said:

 

But it's still going forwards!!!

 

 

Obviously the direction a loco faces determines what is forward and what is reverse.

 

You have to decouple your notion of left v. right from forward v. reverse. The direction in DCC is always relative to the loco you are driving, not the layout.

 

Which is a root problem of DCC, I much preferred in and out based on the layout itself irrespective of loco orientation. Far easier to work with, especially with non-steam traction. I doubt I will drop DCC, there are other advantages to it, but from my perspective it has this fundamental flaw which cannot easily be overcome. I am sure a lot of people like it the way it is, sadly I am in a probable minority being used to circa 60 years of the traditional approach, but I find this new way less intuitive for any non-steam traction and thereby occasionally problematic.

[Ron Ron Ron]

John, not wishing to be rude or anything.....never mind left and right or forward and reverse, you seem to have turned logic upside down on its head. 
Forward is forward and reverse is reverse. It has nothing to do with the direction of travel on the track, relative to your vantage point.

 

If I may say so, your problem appears to be a failing to recognise the fundamental difference between controlling a layout, that happens to have locos and trains on it. (DC)........and independently driving the locos themselves (DCC).

 

Think of your PowerCab as a remote control, that simply allows you to send instructions to the loco that you wish to drive.
Completely forget about the track power and the rails and just imagine those instructions are somehow magically received by the decoder inside the selected loco.

The decoder then responds to the instructions you have given it and drives, or controls the loco. i.e. the decoder is the controller.
 

Put it another way. If you drive a car, forward gears allow the car to go forward and reverse gear does the opposite. It doesn’t matter which way the car is facing on the road.

This is exactly the same as in a prototypical railway locomotive, or train. The train driver selects forward or reverse and the loco/train responds accordingly.

This is what you are doing when driving model trains using DCC.  Effectively replicating a train driver selecting the direction of travel of the loco/train.

 

Your issue is not a fundamental flaw with DCC, as you state, but quite the opposite.
Independent control of model locos/trains, has been the holy grail of model train control since the days of clockwork. Since electricity was first introduced into the equation, there were numerous efforts to bring that about, with almost a couple of dozen “systems” or methods being tried from the late 1940’s until DCC emerged in the 1990’s .  DC has only ever been a stopgap or workaround in the absence of a viable technological solution to independent train control.

Any further technological developments and advances in model train control will only continue in that direction (no pun intended). There will never be a going back to “controlling the track”.

 

 

.

Edited October 27, 2020 by Ron Ron Ron

[john new]

44 minutes ago, Ron Ron Ron said:

John, not wishing to be rude or anything.....never mind left and right or forward and reverse, you seem to have turned logic upside down on its head. 
Forward is forward and reverse is reverse. It has nothing to do with the direction of travel on the track, relative to your vantage point.

 

If I may say so, your problem appears to be a failing to recognise the fundamental difference between controlling a layout, that happens to have locos and trains on it. (DC)........and independently driving the locos themselves (DCC).

 

Think of your PowerCab as a remote control, that simply allows you to send instructions to the loco that you wish to drive.
Completely forget about the track power and the rails and just imagine those instructions are somehow magically received by the decoder inside the selected loco.

The decoder then responds to the instructions you have given it and drives, or controls the loco. i.e. the decoder is the controller.
Er 

Put it another way. If you drive a car, forward gears allow the car to go forward and reverse gear does the opposite. It doesn’t matter which way the car is facing on the road.

This is exactly the same as in a prototypical railway locomotive, or train. The train driver selects forward or reverse and the loco/train responds accordingly.

This is what you are doing when driving model trains using DCC.  Effectively replicating a train driver selecting the direction of travel of the loco/train.

 

Your issue is not a fundamental flaw with DCC, as you state, but quite the opposite.
Independent control of model locos/trains, has been the holy grail of model train control since the days of clockwork. Since electricity was first introduced into the equation, there were numerous efforts to bring that about, with almost a couple of dozen “systems” or methods being tried from the late 1940’s until DCC emerged in the 1990’s .  DC has only ever been a stopgap or workaround in the absence of a viable technological solution to independent train control.

Any further technological developments and advances in model train control will only continue in that direction (no pun intended). There will never be a going back to “controlling the track”.

 

Yes there is an obvious solution, fit couplings to both ends of my diesels, and make sure by a test in every running session that the loco is put on the track orientated the way I want forwards to always be. (Lifting and turning if wrong) Where this begins to be problematic is with locos like the Hattons 66 where to put the couplings on the other end risks damaging the body shell.

 

Realistically though no point discussing it further as we will always differ. I appreciate your point (and DCCers regularly raise it) but  after years of getting used to what often gets called driving the track not the train it is my preference*. I know enough to know diesels have an A & B cab, but not enough to quickly recognise which end is which if it is not something with a definitive cab/hood configuration like a Cl 20 or a shunter.

 

I hadn't appreciated before experimenting with DCC how much I find driving the track the intuitive way to do it because my diesels always go directionally in the way I expect.

 

 * wording changed from  - for traditionally brought up modellers we are -

 

Edited October 27, 2020 by john new
Changed my wording for clarity

[Dagworth]

6 minutes ago, john new said:

but for traditionally brought up modellers

Not so traditional as to have grown up with three rail where locos go forwards regardless of which way they are placed on the track though? Your "driving the track" for direction only became a thing when two rail DC came into play.

 

Andi

[john new]

Just now, Dagworth said:

Not so traditional as to have grown up with three rail where locos go forwards regardless of which way they are placed on the track though? Your "driving the track" for direction only became a thing when two rail DC came into play.

 

Andi

 

I also ran three-rail alongside my 2-rail set up until the 1990s as a show layout but don't recollect the similar issue with HD's Deltic/Green diesel (I have one of each but they are out of use currently) but guess I must have done. The shunter & Bo-Bo were obvious; although I have forgotten now which way round was right, the Co-Bo was also easy to get right first time. 

[BromsMods]

2 hours ago, john new said:

Yes there is an obvious solution, fit couplings to both ends of my diesels, and make sure by a test in every running session that the loco is put on the track orientated the way I want forwards to always be. (Lifting and turning if wrong) Where this begins to be problematic is with locos like the Hattons 66 where to put the couplings on the other end risks damaging the body shell.

 

I understand the issue when you have to pack away a layout rather than having a permanent setup. Although I have a permanent layout I always program my locos on the programming track and, making sure they are orientated the correct way for my purposes, program the forward direction to always be to the left of the programming track.  This provides consistency and negates the necessity to check direction again once they are placed the right way round on the layout (I always place locos so that the forward end is to the left).  You could easily identify the forward direction in your situation by placing a coloured sticker on the underside of the loco at the forward end so that once you come to put the loco back on the track it is the correct way round. This would save having to do any testing for direction.

[Sol]

I fixed the problem on my layout with all locos that stay on the layout ( 26 of with at least 15 run each 2 hour operate session)  in having all forward going to the right & reverse to the left - just like DC days & the crew find this easy

Of course steam are easy but double ended diesels without lights made it a tad harder so the fans are always forward.