Holcombe - an SDJR branch line terminus

[RobAllen]

29 minutes ago, RailWest said:

I've never tried this for real, but....why not have a the bus as a complete loop around the layout

I've not done enough research, but I'm pretty sure that I've read that you shouldn't loop a DCC bus. at 2m long in each direction of the "L", I'm not worrying too much about it all as it's a relatively small layout. I'm not totally sure if I'll bother with an accessory bus yet!

[5BarVT]

2 hours ago, RobAllen said:

I've not done enough research, but I'm pretty sure that I've read that you shouldn't loop a DCC bus. at 2m long in each direction of the "L", I'm not worrying too much about it all as it's a relatively small layout. I'm not totally sure if I'll bother with an accessory bus yet!

In theory, even with d.c., a circuit is a transmission line, and unterminated or looped you get ringing and interference.  It’s just that the frequency is so low that the signal isn’t degraded.  As the frequency increases the delays on the line increase too and eventually get to the point where they destroy the signal.  At 8kHz a DCC signal is fairly robust, but no point in presenting it with extra distortion by looping it round.

Accessory bus isn’t really to do with power loss etc, it’s more about what happens when you drive into a wrongly set point and short the DCC output.  It becomes likelihood x annoyance!  If everything is wired to a common bus it’s much more difficult to sort later when the annoyance gets you.  My suggestion would be to wire back to the control box separately even if they common up in there.  So much easier to sort if (when?!) you decide you need to.

Paul.

[RobAllen]

13 hours ago, 5BarVT said:

If everything is wired to a common bus it’s much more difficult to sort later when the annoyance gets you.  My suggestion would be to wire back to the control box separately even if they common up in there.  So much easier to sort if (when?!) you decide you need to.

Fantastic point Paul! I'll pick up two different colours and run a separate bus for the IP digital points.

[5BarVT]

7 hours ago, RobAllen said:

IP digital points.

With a separate accessory bus, you don’t use the ‘frog’ output from the cobalt.  You wire the track bus to one of the switches and the common from that to the frog.  (Sorry if that means going back and changing what you’ve done already.)

Paul.

[RobAllen]

11 minutes ago, 5BarVT said:

With a separate accessory bus, you don’t use the ‘frog’ output from the cobalt.  You wire the track bus to one of the switches and the common from that to the frog.

Fortunately, I was already aware due to some excellent posts on this forum.
As I understand it, the advantage of the accessory bus is that when I short the track bus due to not setting a point correctly, I can still drive the point motor via the accessory bus.

I haven't actually got as far as installing a point motor yet, but my plan is to do one and get it working all the way from JMRI's panel with control via WiThrottle before I do the second one.
 

[RobAllen]

Not much activity around here as I've been away for work and generally overextended with life stuff.

For my birthday a week or so ago, I received a display case, which I have now assembled and populated with some of my dad's OO-gauge locos.


 

You can see where his interests lie. He was born in Leicester and watched the trains on the Midland main line in the '30s & '40s  and then modelled Bath Queen Square throughout my childhood.

(To be clear, he's still alive. However, the onset of vascular dementia since his stroke is now to the point where he can no longer actively model)

Edited yesterday at 07:46 by RobAllen

[RobAllen]

Laid the track for the sidings this today.

 

Firstly, I completed the curve and the point.

 

and then laid the straight track

 

 

Seems okay.

 

[RobAllen]

Today's the first day I've had since May to model, so I finished wiring the power bus. 

 

 

At this stage it really is "Just two wires" (+ droppers)! 

 

[Jules]

On 26/05/2024 at 09:09, RobAllen said:

Not much activity around here as I've been away for work and generally overextended with life stuff.

For my birthday a week or so ago, I received a display case, which I have now assembled and populated with some of my dad's OO-gauge locos.

Nice collection of locos!  Can I ask the source of the display case?  I have been looking for something similar to store my 'spare' locos!

[RobAllen]

2 hours ago, Jules said:

Nice collection of locos!  Can I ask the source of the display case?  I have been looking for something similar to store my 'spare' locos!

Thanks.

The display case is this one from Amazon: https://www.amazon.co.uk/dp/B08VDRTJ8W. 
 

[RobAllen]

This is the current state of play:


 

I'd like to create the platform in position as I think that will give it more of a sense of place. I will also start running the layout to find out how good the track work is before ballasting.

Next steps are to install the point motors and work out where to place the electro magnets and install them. Hopefully I'll make some progress today.

 

[pacerman]

I like how the track isn’t parallel to the edge of the board, I think it feels more natural that way and it doesn’t look like a train set.  

[MAP66]

Nice steady progress Rob, keep up the good work. Running the layout with some shunting movements should give you a good idea of where best to site the electro magnets for the uncouplers.

[RobAllen]

It's Father's Day today, so both kids are home. Eldest has a practical bent which he channels into working on his car. Today though, he's helping with the electrics. We're going to install a single Cobalt Digital IP point.

First step is to install a DCC circuit breaker to separate the power bus from the accessory bus and test it.

[RobAllen]

First working point!
 

This one proves the concept. There's a separate accessory bus as the power bus is the other side of a DCC circuit breaker.

I'm using Cobalt Digital IP point motors and have registered them on JRMI and you can see the first one working here via WiThrottle on the phone.

Edited 15 hours ago by RobAllen