Wiring a DC loop and siding help please?!

[Grafarman]

Hi all,

Really sorry for the basic question, but I've read so many forums on wiring now I'm completely confused  , and just need help with my specific situation.

 

Here it is:

 

 

The arrow on the left is the main feed and I've marked where the points are.  They are OO finescale electrofrog points, which will be manually operated.  They have a wire coming from the frog which I assume I need to include in the wiring somewhere.

 

The train comes in from the left into the top line, runs around the train and pulls it back out. 

However, there may be a need to leave the loco in the loop and bring another loco onto the back of the train to pull it out.

The siding at the top needs to be shunted as well, usually drawn off the front of the train, possibly whilst another loco stands in the loop.

 

I hope that's clear; I know what I mean so am happy to go into more detail if need be!!

 

Please can someone tell me where to put regular and/or insulated joiners and power feeds, and what switches I need to buy and how to wire them up (ie which wire goes to which bit of track) so I can achieve the above. 

 

Many thanks for your assistance!

 

 

David

 

 

[Steven B]

The basic rule for all two rail wiring (DC or DCC) is to never feed power into a point from the two track end.

 

 

For your track plan you'll need three feeds and three isolated joints:

 

The red line mark the track joints where isolating rail joiners are needed. For ease of installation put the isolating joiners on both rails at the indicated joint (i.e. six needed in total). 

 

The arrows indicate the track feeds. If using two colours of wire (e.g. black and red) ensure the same colour is always attached to the same rail, i.e. black to top rail, red to bottom.

 

If is possible to reduce the number of feeds and the number of isolating joiners but there's no point in creating more confusion!

 

If you're running two locos at once then you'll need to switch the track feeds between the different controllers.

 

Switching the frog using the attached wire isn't essencial but will improve reliability. How its done depends on how you plan to control the points. Some point motors come with built in switches and others allow them to be added. If using a mechanical system (wire in tube, manual) then you'll need to include a micro-switch in the mechanism. Using a single-pole double thrown switch attach the common output of the switch to the frog wire, connect the other two wires to the track feeds. You'll have a 50/50 chance of getting it right first time. If you get a short swap the black and red track feeds over.

 

 

Happy modelling.

 

Steven B.

[Grafarman]

The basic rule for all two rail wiring (DC or DCC) is to never feed power into a point from the two track end.

 

 

For your track plan you'll need three feeds and three isolated joints:

Wiring.jpg

 

The red line mark the track joints where isolating rail joiners are needed. For ease of installation put the isolating joiners on both rails at the indicated joint (i.e. six needed in total). 

 

The arrows indicate the track feeds. If using two colours of wire (e.g. black and red) ensure the same colour is always attached to the same rail, i.e. black to top rail, red to bottom.

 

If is possible to reduce the number of feeds and the number of isolating joiners but there's no point in creating more confusion!

 

If you're running two locos at once then you'll need to switch the track feeds between the different controllers.

 

Switching the frog using the attached wire isn't essencial but will improve reliability. How its done depends on how you plan to control the points. Some point motors come with built in switches and others allow them to be added. If using a mechanical system (wire in tube, manual) then you'll need to include a micro-switch in the mechanism. Using a single-pole double thrown switch attach the common output of the switch to the frog wire, connect the other two wires to the track feeds. You'll have a 50/50 chance of getting it right first time. If you get a short swap the black and red track feeds over.

 

 

Happy modelling.

 

Steven B.

 

Very many thanks indeed Steven for a swift and comprehensive response; you've no idea how much that's helped!

 

One very quick question: if I'm using one controller will I need to switch between the 2 end feeds, and if so what kind of switches would I need (I assume the original feed would remain?)

 

Thanks

 

David

[BR60103]

David:

If you just have one controller (with one knob), you can use standard on/off switches at each of the blocks (called SPST - single pole, single throw) in one of the feeds e.g. in all the red feeds.

 

The wire from the frog is a refinement. You can use it to power the frog so that you don't rely on contact of the points to carry electricity. This is covered in the instructions that come with the points. There's a lot of debate on how necessary this is.

[DCB]

Personally I would just use jump wires as shown the purple one connects to the frog of point B so setting the point to the curved position isolates the dead end beyond D  The double red lines are isolators.

 

If you want more operating capability then three feeds could be arranged 1/2/3 see below, I prefer  DPDT switches  or rotary switches rather than Common Return, and for the diagram below you could do three separate movements if you had three controllers, though why would one want to?   I would put the isolators x near the left hand point, most people would put them at  y   but either way make sure point C is set correctly or you will gat a same side short if a loco crosses the isolator, not too serious in DC unless you give it full power thinking it has staled as this can fry  plunger pick ups on locos such as on the Airfix 14XX.  Obviously with DCC the controller setting is irrelevant the with 20v and 4 amps plunger springs simply overheat and fail

 

 

 

 

 

 

Actually the configuration of tracks is fairly unprototypical, the same number of points would provide the layout as below rather like Blagdon either as a terminus of through station and requires just two isoators on the frog rails , see details.  Prototype practice at least GWR wise almost invariaby used the running line as a headshunt  

[Grafarman]

Personally I would just use jump wires as shown the purple one connects to the frog of point B so setting the point to the curved position isolates the dead end beyond D  The double red lines are isolators.

 

If you want more operating capability then three feeds could be arranged 1/2/3 see below, I prefer  DPDT switches  or rotary switches rather than Common Return, and for the diagram below you could do three separate movements if you had three controllers, though why would one want to?   I would put the isolators x near the left hand point, most people would put them at  y   but either way make sure point C is set correctly or you will gat a same side short if a loco crosses the isolator, not too serious in DC unless you give it full power thinking it has staled as this can fry  plunger pick ups on locos such as on the Airfix 14XX.  Obviously with DCC the controller setting is irrelevant the with 20v and 4 amps plunger springs simply overheat and fail

 

 

 

 

 

 

Actually the configuration of tracks is fairly unprototypical, the same number of points would provide the layout as below rather like Blagdon either as a terminus of through station and requires just two isoators on the frog rails , see details.  Prototype practice at least GWR wise almost invariaby used the running line as a headshunt  

 

Many thanks indeed for this; some useful info there and I'll put it all together when considering the options.

 

Prototypically, it's actually the current layout at Llangollen - maybe not authentic WR practise, but this is how it's laid out in the station area...there, you see, I've given my plan away now!  Nothing settled as yet, just getting the info together for an 'as and when' side project...

 

Thanks again

 

 

David

[DCB]

LLangollen was where the double track from Ruabon became single, it also had extended platforms for Eistedfodd traffic and a separate goods yard, hence it's track layout in preservation is not standard configuration.

[chaz]

Personally I would just use jump wires as shown the purple one connects to the frog of point B so setting the point to the curved position isolates the dead end beyond D  The double red lines are isolators.

 

 

 

 

 

Something wrong here. That pink wire just below the letter D - if that links the crossing of that point to the rail shown then there is going to be a full short when a loco tries to crossover. Not good for either DC or DCC. If you are going to wire the crossings (frogs), and my advice is that you should for good stall-free running, then you MUST switch the feed to change the polarity when the points are changed.

 

just trying to be helpful.

 

Chaz

[Grafarman]

Something wrong here. That pink wire just below the letter D - if that links the crossing of that point to the rail shown then there is going to be a full short when a loco tries to crossover. Not good for either DC or DCC. If you are going to wire the crossings (frogs), and my advice is that you should for good stall-free running, then you MUST switch the feed to change the polarity when the points are changed.

 

just trying to be helpful.

 

Chaz

 

Hi Chaz; here we are again!  I may just opt for the simplest version for this layout as it's not as complicated as Prestatyn! 

I'll include your advice when I come to do some actual tracklaying, and put feeds to the frogs as well as the individual track sections.

 

Thanks for the input

 

David

[Suzie]

I think that this should fulfill the brief:-

 

 

Connect the black feeds together as a sort of common return, use the left red feed as the main feed and connect the other red feeds via switches so that you can isolate a loco there if required.

 

Trains can be isolated in the loops by simply changing the point on the left.

 

Each of the frogs will need to be fed from red and black via a SPDT switch that operates with the point.

 

 

[Brian]

You don't have to wire the frog to anything, you can if wished just rely on the points moving switch rails making contact onto the outer stock rail. Much the same as an insulated frog point switches the track power.

 

However, this isn't always the best option, and adding a SPDT switch which works with the point blade and flips the frogs polarity removes the sole reliance on the points blades making good contact onto the stock rail when closed together.

[chaz]

Hi Chaz; here we are again!  I may just opt for the simplest version for this layout as it's not as complicated as Prestatyn! 

I'll include your advice when I come to do some actual tracklaying, and put feeds to the frogs as well as the individual track sections.

 

Thanks for the input

 

David

 

No problem. My practice, admittedly in 7mm, is that every piece of rail should be connected to the power, either directly or through switches. I'm also doing that on my new On30 layout that uses Peco 4mm code 100 in the fiddle yard.

[DCB]

Something wrong here. That pink wire just below the letter D - if that links the crossing of that point to the rail shown then there is going to be a full short when a loco tries to crossover. Not good for either DC or DCC. If you are going to wire the crossings (frogs), and my advice is that you should for good stall-free running, then you MUST switch the feed to change the polarity when the points are changed.

 

just trying to be helpful.

 

Chaz

 

Yes there is n error but not the purple wire which either goes dead when the point id changed to curved road if insulfrog  or to top rail polarity if live frog, this giving both rails top rail polarity when set to curved.

The error is the green wire which needs to be top rail polarity at all times and not switch with point A as otherwise there is no way to power the lower rail to the right of C as the loco crosses over,it also beeds an insulator between A and C in the top rail to avoid shorts if using live frogs see revised diagram

[Acelauk]

Try this for a simple solution.

 

[DCB]

Thats elegant Acelauk but it does mean the point I labelled as B acts as a section switch for the lower track to the right of the point I marked as C as well as for the upper track to the right of B