[Class45]

Apologies if this has been asked before, but if I buy a DCC loco off E Bay will it work fine on my non DCC layout ?

 

[boxbrownie]

If the decoder has the D.C. mode activated yes, but I never found it that reliable or very good actually.

 

[Class45]

If the decoder has the D.C. mode activated yes, but I never found it that reliable or very good actually.

Oh dear...
There an N gauge Deltic on E Bay at the moment I'd be interested it but I am not going to buy it if there's any chance it won't work as well.
Am I right that having DCC fitted increases the value of the locos ?
If so, having it is not a good thing for a non DCC layout (other than it might be worth more if and when one sells it).

 

[Suzie]

DCC fitted locos will often work better on DC than unfitted locos for a few reasons. These things will often be better:-

1. The lights work at proper brightness all the time.
2. You will get inertia built in to the loco (no need for an inertia controller).
3. Less likely to stall when running slowly.
4. No need to fit a decoder when you convert to DCC.

This is all conditional of course on the decoder that is fitted being any good, and that DC mode is enabled, and that you don't have a fancy PWM controller which can cause problems (a pure simple regulated DC controller is best). I would recommend that you buy the loco, and if you have trouble with it on DC get an inexpensive DCC controller (like a Bachmann E-Z Command for example) and see how it goes with that. An adequate DCC controller costs a lot less than a good DC controller.

 

[34C]

Additional to the above, every model with a DCC decoder in it is only a 12V DC model that has had a decoder added in the circuit from rails to motor. So it can become a DC model very quickly. This can be very simple, unplug decoder, insert blanking plug - if the model version was sold as 'DCC ready' (which means supplied with a socket to take a DCC decoder) this is likely what you will find.

If it is a DIY conversion which in N gauge typically means modification to the circuit, best left alone, as the quality of the work can be very variable.

 

[Class45]

DCC fitted locos will often work better on DC than unfitted locos for a few reasons. These things will often be better:-

1. The lights work at proper brightness all the time.
2. You will get inertia built in to the loco (no need for an inertia controller).
3. Less likely to stall when running slowly.
4. No need to fit a decoder when you convert to DCC.

This is all conditional of course on the decoder that is fitted being any good, and that DC mode is enabled, and that you don't have a fancy PWM controller which can cause problems (a pure simple regulated DC controller is best). I would recommend that you buy the loco, and if you have trouble with it on DC get an inexpensive DCC controller (like a Bachmann E-Z Command for example) and see how it goes with that. An adequate DCC controller costs a lot less than a good DC controller.

Thanks for that.
I have an AGW PE404 twin controller, it's at least 20 years old I believe, so would that count as being none PWM ?

Also I have a couple of Relcos in the circuits, are they a bad idea for a DCC loco ?

 

[Class45]

Additional to the above, every model with a DCC decoder in it is only a 12V DC model that has had a decoder added in the circuit from rails to motor. So it can become a DC model very quickly. This can be very simple, unplug decoder, insert blanking plug - if the model version was sold as 'DCC ready' (which means supplied with a socket to take a DCC decoder) this is likely what you will find.

If it is a DIY conversion which in N gauge typically means modification to the circuit, best left alone, as the quality of the work can be very variable.

I believe the loco's box has "6 DCC" on it so I am assuming it was DCC from new ?

 

[34C]

I believe the loco's box has "6 DCC" on it so I am assuming it was DCC from new ?

I would read that as 'DCC ready' meaning only that it has a decoder socket installed, ( which is a 6 pin type ) so it was produced and sold as a DC loco. This leaves the choice of decoder to the owner.

Next question, does the vendor mention that a DCC decoder has been installed? If not then it's a DC loco.
If a decoder has been installed, then this is easily removed, and with the blanking plug in the socket, it's a DC loco again.

For completeness:
If sold with a decoder installed by the manufacturer then it would have 'DCC fitted' on the box.
If sold with a sound decoder installed by the manufacturer then it would have 'DCCsound' on the box

 

[Suzie]

Thanks for that.
I have an AGW PE404 twin controller, it's at least 20 years old I believe, so would that count as being none PWM ?

Also I have a couple of Relcos in the circuits, are they a bad idea for a DCC loco ?

I cannot find any information on that controller, but it looks to be of sufficient vintage to be OK with DCC decoder fitted locos.

I would not recommend the use of a Relco with a DCC fitted loco, the high voltage spikes are likely to upset the decoder, so just switch it off when using a DCC fitted loco.

The 6-DCC indicates that the loco will have a NEM651 socket for the decoder, a popular socket in older N-gauge locos. Expect to have Next-18 or PluX-16 sockets in newer N-gauge locos.

 

[butler-henderson]

If its new then it will run perfectly fine on dc - the "6 DCC" simply indicates the socket that is fitted and hence the tyope of decoder that is needed. Its only iif it is sold as "DCC Fitted" does it come with a decoder intalled. If its not new then a decoder may have been added but normally that is clear in the description and the decoder can simply be removed and a "blanking plug" fitted to allow it to run without any issues on dc.

 

[Class45]

If its new then it will run perfectly fine on dc - the "6 DCC" simply indicates the socket that is fitted and hence the tyope of decoder that is needed. Its only iif it is sold as "DCC Fitted" does it come with a decoder intalled. If its not new then a decoder may have been added but normally that is clear in the description and the decoder can simply be removed and a "blanking plug" fitted to allow it to run without any issues on dc.

I feel you are right. The seller does not say it is DCC in his description and would if it was because it'd make it more valuable, so it is probably not set up for DCC, it's just DCC compatible if req.

 

[Graham Plowman]

Also I have a couple of Relcos in the circuits, are they a bad idea for a DCC loco ?

This is actually a very important question.

Relcos are a very bad idea for DCC layouts: DCC and Relco Units - Model Railways On-Line

They output high-frequency 50v spikes. The NMRA specification for voltage tolerance of decoders is 29v (IIRC). This means that Relcos are outputting a voltage which is double what decoders are designed to accept, therefore, the use of Relcos with DCC is highly likely to damage all of your decoders very quickly!

Having said that, more expensive decoders have overload circuitry built in which may well shut their decoders down to protect them, but I would suggest that it isn't worth trying to find out.

Having accidentally connected a Relco to a DCC track on my work bench, I can confirm that a DCC command station will actually destroy the Relco.

Also remember that Relcos are a 'continuity maintaining' device. They are not 'track cleaners' as they were advertised as. At best, they put off the evil day of track cleaning for longer. They detect a broken circuit and output a high frequency voltage spike to ionise the gap. This has the effect of restoring the circuit and enabling a loco to continue.
I used Relcos extensively in my DC days and found them to be very effective on small layouts, but less so on larger layouts as they seemed to be 'quenched' as more track length was added.

Relcos are redundant on DCC layouts anyway. DC control changes the voltage across the rails from 0 to 12v to maintain speed. In DCC, there is a constant 16vac supply across the rails and decoders drop the voltage from that to motors inside a loco in order to achieve speed control. There is no drop of track voltage in DCC to make things run slower. In my opinion, this constant track voltage is probably the single most important 'un-sung' benefit of DCC as it very significantly improves operational performance through not having low voltages. This benefit negates the need for Relcos on DCC layouts. And as a result, most people get far better performance with DCC operation than DC. So long as they don't use 14 or 28 speed steps...

 

[Class45]

This is actually a very important question.

Relcos are a very bad idea for DCC layouts: DCC and Relco Units - Model Railways On-Line

They output high-frequency 50v spikes. The NMRA specification for voltage tolerance of decoders is 29v (IIRC). This means that Relcos are outputting a voltage which is double what decoders are designed to accept, therefore, the use of Relcos with DCC is highly likely to damage all of your decoders very quickly!

Having said that, more expensive decoders have overload circuitry built in which may well shut their decoders down to protect them, but I would suggest that it isn't worth trying to find out.

Having accidentally connected a Relco to a DCC track on my work bench, I can confirm that a DCC command station will actually destroy the Relco.

Also remember that Relcos are a 'continuity maintaining' device. They are not 'track cleaners' as they were advertised as. At best, they put off the evil day of track cleaning for longer. They detect a broken circuit and output a high frequency voltage spike to ionise the gap. This has the effect of restoring the circuit and enabling a loco to continue.
I used Relcos extensively in my DC days and found them to be very effective on small layouts, but less so on larger layouts as they seemed to be 'quenched' as more track length was added.

Relcos are redundant on DCC layouts anyway. DC control changes the voltage across the rails from 0 to 12v to maintain speed. In DCC, there is a constant 16vac supply across the rails and decoders drop the voltage from that to motors inside a loco in order to achieve speed control. There is no drop of track voltage in DCC to make things run slower. In my opinion, this constant track voltage is probably the single most important 'un-sung' benefit of DCC as it very significantly improves operational performance through not having low voltages. This benefit negates the need for Relcos on DCC layouts. And as a result, most people get far better performance with DCC operation than DC. So long as they don't use 14 or 28 speed steps...

So would it be OK to use Relcos on a DCC ready loco which hadn't actually been converted to DCC ?

 

[34C]

So would it be OK to use Relcos on a DCC ready loco which hadn't actually been converted to DCC ?

In principle yes, as it is a 12V DC loco.

Personally I wouldn't use a device of this sort on the size of motors in N gauge product, because it cannot discriminate between loss of conduction at railhead and commutator; and I believe many small motors now use a fine metal wiper on the commutator, rather than the much more tolerant piece of copper carbon.

 

[boxbrownie]

DCC fitted locos will often work better on DC than unfitted locos for a few reasons. These things will often be better:-

1. The lights work at proper brightness all the time.
2. You will get inertia built in to the loco (no need for an inertia controller).
3. Less likely to stall when running slowly.
4. No need to fit a decoder when you convert to DCC.

This is all conditional of course on the decoder that is fitted being any good, and that DC mode is enabled, and that you don't have a fancy PWM controller which can cause problems (a pure simple regulated DC controller is best). I would recommend that you buy the loco, and if you have trouble with it on DC get an inexpensive DCC controller (like a Bachmann E-Z Command for example) and see how it goes with that. An adequate DCC controller costs a lot less than a good DC controller.

.1. I am not sure the lights would work at full brightness all the time, with a DC controller through a decoder you are still only putting a few volts through to make it move, the same (if not less) volts than would be required on D.C. without a decoder fitted.

.2. Why? Unless the Loco has a stay alive fitted, and I am not even sure that a stay alive would work as well running on D.C.

Not wishing to be confrontational it’s just that are my impressions if running DC on a DCC fitted Loco, I cannot see how you can fool physics.

If indeed your correct it sounds to good to be true, but happy to see it work that way for sure

 

[Suzie]

DCC decoders don't tend to start the loco moving until you have at least 5V on the track, enough to make the lights light up in most cases. The DCC decoder needs a bit of power to run the electronics, and once it has enough it can run most of the decoder features.

 

[Suzie]

A DC loco should have a capacitor across the motor terminals, and this will shunt the high frequency from the Relco preventing it from damaging the motor. DCC decoders have something similar that protects the decoder, but some less sophisticated decoders do not have all of their connections properly protected against high voltages on the track.

 

[Graham Plowman]

So would it be OK to use Relcos on a DCC ready loco which hadn't actually been converted to DCC ?

The definition of 'DCC Ready' is a loco which has a DCC socket fitted, into which a blanking plug has been inserted, meaning that the owner can subsequently remove the blanking plug and plug in a decoder.

The key is the presence of a decoder, not how the loco is wired.

So long as a loco has NO decoder fitted, it can be run on a DC layout with a Relco, regardless of whether it is 'DCC Ready' or not.

 

[Graham Plowman]

In principle yes, as it is a 12V DC loco.

Personally I wouldn't use a device of this sort on the size of motors in N gauge product, because it cannot discriminate between loss of conduction at railhead and commutator; and I believe many small motors now use a fine metal wiper on the commutator, rather than the much more tolerant piece of copper carbon.

To be honest, I found that of all the gauges/scales, Relcos were actually most beneficial on N gauge products, in my case, 009.

 

[Graham Plowman]

1. The lights work at proper brightness all the time.
2. You will get inertia built in to the loco (no need for an inertia controller).
3. Less likely to stall when running slowly.
4. No need to fit a decoder when you convert to DCC.

.1. I am not sure the lights would work at full brightness all the time, with a DC controller through a decoder you are still only putting a few volts through to make it move, the same (if not less) volts than would be required on D.C. without a decoder fitted.

.2. Why? Unless the Loco has a stay alive fitted, and I am not even sure that a stay alive would work as well running on D.C.

Not wishing to be confrontational it’s just that are my impressions if running DC on a DCC fitted Loco, I cannot see how you can fool physics.

If indeed your correct it sounds to good to be true, but happy to see it work that way for sure

My observations on this:

1. This depends on the decoder, some do, some don't.
2. DCC decoders have voltage controls built in to tightly control the voltage supplied to a motor. These are based on the principal of dropping the voltage from a higher voltage. You can never get more voltage out than you put in. So while a DC controller drops the track voltage, the decoder will be trying to maintain the voltage to the motor, but won't be able to due to insufficient track voltage. You are likely to get a conflict here with undesirable/uncontrollable behaviour.
3. This is not true. The DC track voltage is dropping off, so the effect will be exactly the same as it is for normal DC operation with no decoder fitted: it is more likely to stall due to continuity issues between rail/wheel with low voltages
4. That is true because the loco will already have a decoder fitted.

My suggestion is: don't bother running DCC fitted locos on DC. They will never exhibit their full functionality to its potential, therefore, running on DC is always going to result in disappointment. Move to DCC and you won't look back!