Track plan Layout 6/14 DCC Wiring

[Rosco100uk]

Hi

I've build a new layout based on the above track plan, from track plan 14th edition.

I was going to use conventional analogue power, but have now decided to go down the DCC route.

I need a bit help.

I have bought a Hornby Select

I have 15 point motors to supply, how many digital accs decoders R8247 do i need?

I also have 10 colour light signals, 6 plaza lights, 20 platform light, about 25 lights in various builds and 20 street lights

What else do i need to buy

Any help would be welcome

[Chrissaf]

Each R8247 has 4 ports, typically 1 port is used for each Solenoid point motor [the R8247 does not natively support other types of point motor]. So 15 points equates to four R8247's [4 x 4 = 16 ports capacity]. However, if your layout uses points to cross-over from one oval to a second oval, then these two points would operate together. Thus two points could share the same R8247 port. Subject to how many 'cross-overs' are designed into the layout [i do not have access to your proposed 6/14 plan], then the total number of required R8247 ports could be reduced down from 15.

With regard the 10 colour light signals, these could optionally be powered and controlled using a R8247 port, but ONLY if they are two aspect signals [i.e two colours such as red & green] as three and four aspect signals are not natively supported by the version 1 R8247. So this would add another three R8247's [12 ports] to the count making 7 x R8247s in total.

Note that the Select can only use Accessory Decoder addresses in the range 61 to 99 making 38 addresses [ports] in total, which equates to 9.5 x R8247 decoders. Which really means 9, so your potential 7 is close to the maximum limit.

Note that using a Select or indeed an Elite to control both points and signals in relatively high numbers requires a lot of button pressing, particularly as the signals are potentially changing state on a consistently regular basis as the trains traverse the layout. I suggest that after a while the novelty of trying to keep the signal state synchronised using the Select and R8247s will soon wear off and you will wish that you had purchased a signal product that included some form of autonomous auto-operation such as those made by Train-Tech.

Note that to configure the R8247 to support signals you will need to use a Select with either version 1.6 or version 2.0 firmware. So if your Select purchase was 'second-hand' then the firmware revision needs to be checked.

With such a high number of attached R8247's the standard factory Select 1 amp power supply is very likely to need to be replaced with the Hornby P9300 4 amp power supply as an upgrade.

With regard the other general layout lighting requirement [approximately 71 lamps in total] I strongly advise that you do not try and power these from your Select. All of the Select power should be reserved for operating DCC locomotives and DCC Accessories. I strongly suggest that you power your general layout lighting from a general purpose 12 volt DC power supply with at least 2 amp current capacity, but the cost difference to go to 4 or 5 amps is minimal and would mean the power supply not being at all stressed. This assumes that all general purpose layout lighting is based upon LED lighting products. If the intention is to use incandescent 'Grain of Wheat' bulbs then the power supply would need to be nearer 7 amps [calculated from 71 bulbs times 100mA**. As a 'rule of thumb' GoW bulbs consume about 10 times more current than an LED]. This assumes 12 volt GoW bulbs and not 3 volt or 6 volt ones. All general lighting LEDs should have a 1,000 Ohm 1/4 watt current limiting resistor included in series with each LED when using a 12 volt DC supply.

Note** the 100mA figure includes a safety margin over-head, GoW bulbs typically consume about 60 - 70mA each at their full rated supply voltage.

[96RAF]

The R8247 version 2 can be configured to operate multi-aspect signals by way of using more ports operated in cascade, but this is not something a beginner will likely be able to do.

Train-Tech produces excellent kit and alongside their full range of manual, DCC and auto-sensor signals has a stand alone sensor for use with extant signals. You can download their catalogue and get further details from their website.