St. Mary Hoo - P4 Southern Region third rail

Simon Glidewell

Western Thunderer
Thanks for your observations and kind help Howard; I'll certainly put your wiring ideas to the test, and hopefully that will resolve the issue. If all else fails I will let the third rail take the place of polarity switches, etc, as it works very efficiently. The bisection will be wired accordingly. As to the side exit ramps, the reason I use the S4Soc castings is a pragmatic one. The standard SR type you have employed would give the very fragile pick up shoes I use, an unnecessarily hard time! The ramp on the SR version is short and angled with a high chance of snagging the shoes; the ones I use are very gentle in this respect and have worked perfectly for a number of years. I could have easily replaced them and made my own SR type from nickel silver sheet but I could foresee problems with the locos and EMU's. Apart from this I am a firm believer that there is a prototype for everything, if you look hard enough around the SR system. The classic CLAG article on third and fourth rail is good but I would never use it as a "Bble" to all things SR conductor rail, preferring to find evidence through extensive photo research of my own. St. Mary Hoo has always done things differently, being a real backwater location, and such a situation is quite plausible.

All the best
Simon
 

Simon Glidewell

Western Thunderer
Apologies Simon. I thought it was the point in the picture that was the cause of the problem - oops! But it could still be that you need more polarity switches.

Colin

Don't worry Colin! As to additional polarity switches, I'll try Howard's suggestion first and see where we go from there...

Cheers
Simon
 

Colin Parks

Member
Hi Simon,
I'm sure Howard will have the solution. The more I think about it, it would appear that the bisected turnout's stock rails and closure rails would need to be of different polarity either side of the diamond crossing when the road is set for the diamond rather than either direction on the turnout. (Admittedly, I am finding it hard imagine the polarities from the picture with the wiring and switches superimposed.) In that picture, what is feeding the diamond's K crossing pictured to the left and coloured red?

Colin
 
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Neil

Western Thunderer
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Simon,

I am not sure if you have or have not solved the problem of wiring your crossings yet, but there is an "error"* in the original diagram. If you look at tjhe "A/B" changeover switch, the Blue and Red feeds are both connected to one common feed. However, they should be connected separately - the "top" red and blue should come from the diagonal road as drawn. However, the bottom red and blue should be connected to the red and blue rails at the toe and of the point. As drawn, you might get a short or no feed depending on how the diagonal road is fed in relation to the feed to the toe of the point. ........ Edit:- * not an error if all the reds and blues are commoned together as Neil suggests in his later post.

Thanks for correcting your own post Howard. The schematic diagram represents the simplest way of wiring the formation (in two rail format) and while not commoning up all the red rails together and the blue ones might mean that parts of the formation aren't fed there will be no short circuit. Equally there is no need to pick separate blue and red feeds for top and bottom of the A/B switch.

Hi Simon,
I'm sure Howard will have the solution. The more I think about it, it would appear that the bisected turnout's stock rails and closure rails would need to be of different polarity either side of the diamond crossing when the road is set for the diamond rather than either direction on the turnout. (Admittedly, I am finding it hard imagine the polarities from the picture with the wiring and switches superimposed.) In that picture, what is feeding the diamond's K crossing pictured to the left and coloured red?

Colin

Only the green yellow and magenta sections of the formation need to be switched.

Route A requires, yellow to connect to red, magenta to connect to blue and green to connect to blue.
Route B requires yellow to connect to red, magenta to connect to blue and green to connect to red.
Route C requires yellow to connect to blue, magenta to connect to red and green to connect to either as it's irrelevant.

The red K crossing should be commoned up to all the other red rails; it doesn't require to be switched at all whatever route is selected through the formation.
 

Simon Glidewell

Western Thunderer
Many thanks Colin and Neil. Yet again I am amazed at all the excellent help I am being given by your good selves, and Howard; Dave plus others here! I really am extremely appreciative and will continue to fiddle around with this demon that I have created! Somewhere in amongst all that scrap metal and wire rat's nest, lurks the solution...

Come out, come out... wherever you are!!
 

J_F_S

Western Thunderer
Hello Chaps,

Re Neil's comments on the crossings. The question of a short circuit CAN arise - it all depends on how the bisecting road is fed. The question arises because the road with the point in it, and the diagonal road are actually independent "sections". Hence my saying that there is an error if wired as originally shown. If all the sections are commoned together, then there is only one section, and in that situation - and that one only - it does not matter. However, the short circuit can occur - even if all the sections are commoned - if the crossing road is a branch road off a turnout, and one of the rails is treated as an extension of the crossing ("frog") of that point. In that case, if the formation is wired as per the original diagram, then the short will occur whenever that point is one particular way. Don't know if that applies in Simon's case.

Certainly on my layout, I have a diamond in a similar situation, but it effectively can be connected to any one of four different sections - and I have it wired so that it switches automatically with the points - so I have some experience to speak from!

I understand that people who use DCC often don't bother with section switches. I use switched sections - but even if I were DCC, I would still section all my trackwork otherwise finding a fault would be a nightmare. In my case, even though I use a common return, all my returns are connected via switches for just that purpose!!

Simon, I hear what you say about your shoes needing a gradual entry up the ramp. But(!) it is important to remember that shoes should never climb "up" a ramp. In running roads, ramps were only provided at Facing points. juice rails are always gapped at Trailing points and at points where traffic moved in both directions. In sidings, ramps were provided were provided but only where a gap might cause trains to become "gapped". I am sure you know all of that, but I mention it in case others might miss-hear.

I agree about the CLAG site, we are fortunate that it still exists given that most of the group's members are spread to the four winds! And Green St. will see the light of day this year at Scaleforum.

Just on your use of third rail only running, how do you manage to stop your trains becoming "Gapped" - given it is a big issue on the Real Thing - I well remember the SUBs out of Waterloo; the lights - and the traction power - were "off" more than they were "on"! Are you using "stay-alive" or something?

Best wishes,

Howard
 
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Simon Glidewell

Western Thunderer
Evening folks!

Sorry about my long absence and many thanks for your comments about my wayward point Howard! With a two car EMU with pick ups either end, gapping has not caused any problems. I actually run three rail most of the time with the conductor rail acting as an extra feed. I'm currently building a small LT layout with working third and fourth rail using scalefour society conductor rail and insulators on chaired track. This system runs entirely off the conductor rails and very satisfactorily as well, but all four rails are powered which can be switched on or off.

All the best
Simon
 
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jonte

Western Thunderer
Evening folks!

Sorry about my long absence and many thanks for your comments about my wayward point Howard! With a two car EMU with pick ups either end, gapping has not caused any problems. I actually run three rail most of the time with the conductor rail acting as an extra feed. I'm currently building a small LT layout with working third and fourth rail using scalefour society conductor rail and insulators on chaired track. This system runs entirely off the conductor rails and very satisfactorily as well, but all four rails are powered which can be switched on or off.

All the best
Simon

Welcome back, Simon.

I was getting worried.

Fondest,

Jonte
 

adrian

Flying Squad
Good to hear from you and that you are still modelling.
I'm currently building a small LT layout with working third and fourth rail using scalefour society conductor rail and insulators on chaired track. This system runs entirely off the conductor rails and very satisfactorily as well,
Running at a higher voltage to generate a little arcing? :rolleyes:
 

Yorkshire Dave

Western Thunderer
I'm currently building a small LT layout with working third and fourth rail using scalefour society conductor rail and insulators on chaired track. This system runs entirely off the conductor rails and very satisfactorily as well, but all four rails are powered which can be switched on or off.

Not forgetting tripcock 'thwock' if you have sound as well.
 

oldravendale

Western Thunderer
I'm currently building a small LT layout with working third and fourth rail using scalefour society conductor rail and insulators on chaired track. This system runs entirely off the conductor rails and very satisfactorily as well, but all four rails are powered which can be switched on or off.

All the best
Simon

Can we see Mister, please, please!

Brian
 

Simon Glidewell

Western Thunderer
Many thanks all for your comments gents! I could start a new thread about my LT adventure?

As far as SMH is concerned, I spent quite a bit of time over the Summer modifying a Hornby class 71 for the layout. Obviously converted to P4, the loco uses Gibson tender wheels and as a replacement for the Hornby OO gauge offerings. This was the easy part of the conversion and is not difficult to do. The hard part was closing the gap between the body and bogies, plus adding new bogie cable runs where possible. The finished machine represents a recently outshopped loco used on the Golden Arrow. The photo shows the loco before it was given the GA touches and light weathering. It still needs third rail pick ups. Hornby made a splendid job with this model.FB_IMG_15366078888992070.jpg
 

Simon Glidewell

Western Thunderer
I also built a class 74 in P4 using the Silver Fox resin kit of parts as a starting point. The chassis is very complex and took weeks of consistent work. I studied large numbers of prototype photos to get the bogie cable runs and fuel tank area spot on. The bogies were a nightmare from start to finish as the cabling is incredibly involved and intricate. I chose to add Gibson disc wheels as opposed to the more common spoked, as one or two of the class had these fitted in an attempt to cure rough riding characteristics of the latter. Some 74's had a mixture of both. The model still needs wire handrails and jumper cables, plus a cab interior and engine room detail. It will be flush glazed after painting. Like the 71, it will have third rail pick ups fitted. FB_IMG_15366079012250640.jpg
 
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