I have a medium-large layout that was planned and built for block control in the days before DCC. A few years ago, I removed one DC cab and replaced it with an NCE PowerCab, but this is just wired into track power (for safety I eventually disabled the other DC cab and now run the layout on DCC only, but without a separate bus). I'm beginning to see the advantages of other DCC features like stationary decoders for turnouts and computer interface, but I would like to phase this in. Can I divide my layout into two parts electrically and operate half with a bus and an NCE SB5 and the other half with a PowerCab? What are potential issues?
If I don't write it in the forum, I don't find out if I am ignorant, so don't do anything based on this post, but I think you could add a DCC Specialties circuit breaker or two.
Run the output from that to the "old" feeder based DC section (which is now DCC) and daisy chain the input side to the Bus track or a second circuit breaker.
That would give you better circuit breaker protection than just the power cab and you wouldn't necessarily need a second throttle.
What say the gurus?
Henry
COB Potomac & Northern
Shenandoah Valley
Maybe I can make it a little clearer what I have in mind. I have maybe 20 former DC blocks on the layout. To keep from doing everything at once, I have it in mind to disconnect all track power connections to (say) 10 of those blocks, including the now useless DPDT toggles that used to route DC power. I then install an all new DCC bus and reconnect the 10 blocks to the new bus, along with other devices like stationary decoders.
The other 10 blocks for the time being are left connected to the toggles. The track power circuit to one side of the DPDT toggles remains, it used to carry one cab DC but now is connected to the PowerCab. I provide a connection to the former DC track circuit to the new bus so DCC signal is consistent. The DCC signal now comes at some early stage in the project from an SB5, not the PowerCab, but the PowerCab and a wireless handset continue to provide control.
Are there issues here?
When uses with the SB5, there no longer is a PowerCab, really. You can use the PowerCab panel and power supply as a programming system on your bench but the only output from a combined system comes from the SB5. You can use circuit breakers to divide up the SB5 output, the purpose of this is to keep trains running in one section of the layout if there is a short in a different section. If you tend to only run trains by yourself it's not really a requirement. If you are adding accessory decoders, a good way to wire things is run a bus directly from the SB5 to power all the accessory decoders, and add a single circuit breaker between the SB5 and the bus that powers the rails. That way, if you run against a turnout and short the power, the train stops but the accessory decoder controlling the turnout still has power, so you can change the position of the points to clear the track short.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I understand about the PowerCab, but as I understand it, the PowerCab just becomes a cab with the SB5 and still controls locos, etc. And yes, I mostly run by myself.
That's an interesting idea about the separate bus, but again, I'll be replacing the SPDT switches with diodes controlling the Tortoises gradually. I'll have to think through the best way to do this.
The club I belonged to was wired for DC, fourteen blocks and one reverse loop in the early 1980's. Handlaid track and turnouts and we used #24 telephone wire.
When DCC came along, we switched all the switches on and ran two or three DCC locos for a short while. We just ran #14 buss and connected to the feeders about six to eight inches from where the feeders connected to the track.
A DCC reverser for the reverse loop.
All the PFM turnout machines are on a twelve volt buss along with a few Tortoise.
I would suggest doing the buss method right now.
We use the five amp NCE Power Pro.
I disconnected that system one time and connected up my Power Cab. Worked fine for three sound locos as a test. The MRC reversers did not work with the Power Cab though. Probably not enough current.
One large room and one small room all one layout.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
How does the SB5 handle the programming track? I really like the way the Auto Switch works with the PowerCab programming track. Does the SB5 do anything similar, or is there any other workaround?
SB5 does not have a program track. You use your PCP and power supply to make a program track which is completely independent of the layout. Or keep one of those DPDT toggles for a siding, so in the Cab A position it connect the siding to the track bus from the SB5, and in the Cab B position it connects the siding to the output of the PCP.
Here's a related question that may let me keep the PowerCab over the SB5, since I operate by myself and have never had a problem with the 2 amp limit. My main constraint is that I need more ports than on the PCP panel, which is what I am using. One port is for the PowerCab, one is for another handheld, and one is for an RB02 base station, which I use for the handheld, so theoretically I could get away without that port, but I like to put the handheld back there so I don't lose it.
I want to add a USB port for JMRI. Can I extend the available ports to do this by adding a UTP cab bus fascia panel and connecting it with the RJ12 cable, then connect the USB adapter to the new UTP panel?
UPDATE: On further research, my RB02 has two additional ports, A and B. They are meant for adding remote repeaters, but it looks like they're standard bus connections. Can I run an RJ12 connection to the NCE USB interface through Ports A or B on the RB02?
The UTP panels have 4 total ports, 2 on the front to plug in cabs and 2 on the back to chain the cab bus. Run from the PCP to a UTP, and then from the UTP to the RB2. Problem solved. That PowerCab must always be plugged in to the port on the PCP, but other cabs can be plugged in to any free port.
But what about Ports A and B on the RB02? Can they be used like any UTP port?
No, those are only for repeaters. Different signals, even though the use the same connectors.