Running DCC and non-DCC together???

There are bits & pieces of answers for this in various forums but I would like to confirm it for myself:

1. Can a non-DCC loco and a DCC loco run together on the same track or in different blocks on the same layout- e.g., an MTL loco with an installed decoder and a Marklin loco without one?

2. Are different transformers needed for DCC and non-DCC --- e.g., can the MRC power pack be used for both?

3. turnouts - do remote turnouts need to be modified for DCC? That is, if DCC is only going to be used for the loco, does anything have to be done with the remote turnouts if one switches to DCC?

Dan

Dan, please see below.

1) No, a DC loco will now have "AC" on it and fry (at least get hot) within a minute or two. Since DCC is roughly a "10 Kilo Hertz square wave", sharply switching polarities between 8,000 and 10,000 times per second, a DC motor will just go nuts.

Note: Any DCC loco can run on a DC track however, they take more DC volts to do so, don't run as well and most decoder manufacturers default this option off because of this. It can be used however to make the loco respond differently, like braking to a stop in a automated layout.

2) I'll just say yes here. DCC systems are higher power, several Amperes (Amps or just the A) and usually also specify a specific AC voltage transformer. So I will just say No here to using your MRC or other power pack with AC accessory outputs.

Note again: The AC transformers are normally only with the non-starter sets, mainly the common 5A (that's Amps) or 10A systems more typical of the past HO and O scale layouts that need much more power to run. For us Z (and most all N scalers), we can use the much simpler, much lower cost starter sets like NCE's Power Cab, MRC's Prodigy Express (not the same as NCE even tho the handheld "cab" looks the same) or Digitrax Zepher. These include just a small "wall wart", that plugs into the wall and are very portable systems.

3) Most all turnouts will work as-is DCC, especially all Märklin and MTL. HOWEVER, with DCC, there is constant voltage to the tracks. If a loco (or other metal wheel rolling stock) derails in or on a turnout, this becomes a short that can result in the full DCC current (the Amps part), resulting in 25 to 150 Watts (volts times current) flowing in that metal wheel so it can get hot! Now don't get all freaked out here as all the power supplies quickly self protect, typically in 1/4 or 1/2 second. But they also turn back on again in the same amount of time, effectly pulsing that short so it's not as bad as it reads. Just watch your running trains with DCC. There are electronic circuit breakers and/or a simple light bulb trick that can be done to greatly minimize this. The starter sets take much longer to start so its a non-issue for them.

Note: Just like DC systems, it is best to build blocks. Each block can have a simple current limit protection like NCE's CP6.

Dan,

Buy a starter system and pretty much plug the same two wires in and enjoy. You can do all the other fancy work later. You'll never go back to DC. There are no drop-in decoders for Märklin locos but can be put in with a little work. Steam is a pain however with most decoders going in the tender and wires running to the cab.

Jeff
SF Bay Area Z

Jeff,

Thank you for the very detailed response to my questions.

Dan

I was thinking about getting Velmo decoder for the F7. They make drop in decoders for Maerklin engines from what I seen. (not the steam unfortunately) They are a bit more pricey I think, but you just screw them in. Their web site is also in English, but I really don't know what light effects they have for the F7. I would like dimming and Gyralights but don't know if that is possible with them. Anyone have those in their F7s?

I have the Digitrax Super Empire Builder, DB-150 & DT-400, and there is a section in the manual for operation of analog locos. I have run both at the same time,but just mainly to test the non DCC loco without any problems [that I know of]. This was just a loco test & not permanent.
I'm not an expert, & you got some excellent advice from an expert - listen to him. I just wanted to ad my 2cents concerning my experiences.
I do not run my turnouts on DCC.
Best to you,
Stojiny

My digitrax system allowed for one DC loco to be run with DCC. However, I fried a Marklin steamer this way and don't recommend it in Z scale. There was a high pitched hum and a puff of smoke!

My NCE system does not allow for running of DC locos on the system. The new Train Control Systems Z2 and Z4 decoders allow you to run on DCC and DC without programming the decoder. I will have a toggle switch to switch between DCC and DC on my layout. So, if I want to run some locos that don't have decoders, I can run the DCC ones on DC as well, hoping to remember that they will all be hot at the same time.

I agree that Jeff is the DCC expert around here and defer to him for the technical aspects!

John

The safest way to run dcc and analog locos on the same layout is to use blocks and cab control. When a layout is designed for two power pack cab control, it's very easy to substitute one analog power pack with a digital central. Such layouts would allow running at the same time either 2 analog locos, 1 analog loco and any number of digital ones or dcc only. The only important thing is, that blocks must be fully separated from each other, so both rails must be isolated (common rail wiring doesn't work). For power pack selection, the easiest way is the use of double pole triple throw switches, so the options for each block are: power pack 1, off, power pack 2. This also takes care of cutting power in a block. For purely dcc operation, all switches can be set to power pack with the dcc signal. For analog and mixed operation, the blocks must be switched according to standard cab control rules. No analog loco should ever enter into a block with dcc power selected and digital locos should stay out of blocks set to analog mode.

For accessory (signals and switches) control, either analog or dcc can be used, just make sure that accessory devices get their control signals and power independent from the blocks.

ps: For analog power, the best transformer I found is a modified PC-ATX power supply. Besides being relatively cheap, these devices can output stabilized 12V DC/5V DC and provide around 30 A. The 12V DC source can be used for throttles and switch magnets (with diode logic or just drop it to 10V with a few diodes), while 5V is perfect for lighting, sound systems and powering various digital circuits. The short circuit protection is aggressive and quick enough to protect the trains and power can only be turned back by cycling the main switch of the transformer. The only modifiction required for model railroad use was the installation of a power on switch between the 'power good' output (5V TTL signal) and the low voltage ground.

KVP and others,

Thank you for all the information and advice.

I have one final (???) question - do you need to solder feed wires to the track and do you need to solder some of the track themselves for good dcc operation? In other words, if I do not solder, am I asking for trouble?

Dan

I solder the feeder wires under the rails since it is easier to conceal them. I haven't soldered the rail joiners and have not had a problem yet. Some advocate it, others don't think you need to.

John