Test Track

Whatizit?
DCC Wiki has a page titled “Programming Track“. The article goes into depth on the why and how of using a portion of your layout as a programming track.

That sounded like a good idea to me and I have started to get my track ready. In the meanwhile I got to thinking that a section of track that I could run on DC would make sense. I have a couple of DCC Ready On30 locos and a HO 44-ton switcher intended for an On30 bash. Having the ability to test drive these on DC just makes sense.

With that in mind it then made sense to me to combine all of this .. DCC, Program track and DCC track.

Isolating the Programming Track
Again .. refer back to dccwiki for the full instructions – but basically you are electrically isolating a section of track which will be the program section – at least 50% longer then your than your longest locomotive .. and beyond that .. as long as possible since some locomotives will creep forward during programming. On either end of this program section are isolating sections longer than your longest locomotive. This is so that a locomotive being programmed doesn’t creep across and contact the DCC section.

I am using a section of the main where a siding for the Coke Oven Bank is. This gives me a Test Section that is 38 in. long.

MyPlan

Program Track Switchology
From the DCC Wiki website we have a diagram showing using a 4PDT switch. Flipped up the Booster (DCC) powers the Test Section and the two Isolating Sections. Flipped down the Test Section becomes a Program Track powered from the Command Station. The Isolating Sections are unpowered and a Red LED tuns on (well .. with some DCC systems they power down the DCC when Programming so .. it depends)>

switchology1

Adding a DC Choice via a DPDT Switch
I modified the above diagram by adding a DPDT switch. Power for the Test Section is pulled off of the center terminals of the switch. The DCC Throttle is connected to one side of the switch and the feed from the Command Station is piped from the 4PDT switch.

This works but you only have the one Red LED showing power to the Test Section.

switchology2

Adding a DC Choice via a 4PDT Switch
By adding a second 4PDT switch I am getting closer to what I want. When the left 4PDT switch is thrown down the Red LED lights indicating that the Test Section is powered. When the right 4PDT switch is thrown to “Program” then power is piped from the Command Station to the Test Section and the Program LED lights. When the switch is thrown to “DC” then the Test Section is powered by the DC Throttle and the DC Power LED lights.

I am using the MRC Prodigy Advance and there are outputs for the Booster and Program. Some DCC systems cut the power from the Booster when Programming. If this is true of MRC then I will have to modify the schematic to supply an external DC power to the LEDs.

  • If the left switch is thrown to Booster and the right switch to Program then the DCC works.
  • If the right switch is thrown to DC then DC powers the test section.

The LEDs should make clear what going on. With this design the Program Power LED lit but the Test Track unlit would indicate DCC. I’m not completely happy with this as I would like if the left switch was thrown to Booster then it shouldn’t matter how the right switch is thrown. I’ll see what I can do about that.

switchology3


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