DCC Power Districts

[Mayner]

Although large scale I thought this might be useful for anyone considering or using DCC

 

I recently restored track power to the garden railway after a major re-sleepering programme. Basically I have had to replace about 50% of sleepers on the main line after 7-8 years use as a result of UV damage. Although most of my locos are now battery electric, I though it was a good opportunity to upgrade the DCC system rather than converting all of my locos to on board battery power.

 

Schematic of railway showing power districts

 

The main line has a 2% ruling gradient, the High Line 4% which limits loadings and results in high current draw from locos climbing the grades.

 

I divided the Large Scale layout into separate power districts protected by DCC Specialties Power Shield PSX1 circuit breakers. These both protect the DCC Command station and avoid shutting down the entire railway in the event of a short or a loco de-railing and should simplify trouble shooting.

 

Control system for Large Scale Digitrax DB150 ampmeter, Radio & IR receivers and DPDT isolating switches for Power Districts

 

The circuit breakers have basically eliminated the need to return command stations to Digitrax for in service fault repair.

The circuit breakers are fed through DPDT switches bought from Peats of Parnell St about 40 years ago, the circuit breakers and Digitrax Command station was used on a layout in Dublin before moving to New Zealand in 2004. The radio receivers and radio throttles were bought about 5-6 years ago when we moved up from N to G Scale 

 

Circuit breakers behind panel

 

Hidden away beneath the N Gauge.

 

The DCC control system for the large scale layout lives on a shelf below the baseboards currently used to support the N gauge.

The biggest job was the bonding of rail joints, most of the rail is heavily weathered after 9-10 years use in the humid Waikato climate. The Code 250 brass rails are used to conduct power rather than a parallel power bus, wiring between the shed and individual blocks or power districts is by a combination of mains and outdoor low voltage cabeling.

I clean the web of the rail using 240g wet and dry, and use a cheap 70watt soldering iron with resin cored electrical solder. I use a drop of phosphoric acid flux (10-15%) diluted from a liquid rust convertor (28%) as a wetting agent which improves the flow of solder. The Waikato rain neutralises the flux.

 

[Mayner]

Outdoor soldering station

I made up a soldering iron stand from a piece of 6x2 and an old Litesold stand after picking up the iron by the hot end .

 

The minidrill was for rail cleaning but a piece of wet and dry turned out to be less bother. Container is a rust convertor diluted 50% with water, worked a threat.

 

The leads are fed through an ELCB just in case I do something stupid with the cable.

 

Not terribly clean rails.

 

Tinned

One I did earlier.

 

Allowing for expansion s important, I had joints fail where I did not allow enough. I use an LGB graphite paste for lubricating the fishplates when 1st laying track, which also helpe to maintain conductivity.