Third Rail on Points and in Sidings?

[Ray Von]

So I'll be adding third rail to this layout soon and just wanted to canvas some opinion on "Authentic" third rail placement.

 

The track on the right of the picture is the main line leading in to the layout and will lead directly to a platform on its left - so I can place third rail on the furthest rail from the platform (far right.)

Similarly the tracks parallel to this (at the station) will have third rail mounted on the farthest rail from the platform edge.

 

However, the sidings and the points are more of a puzzle - I'm not sure how to place third rail around points, and I'm guessing - but not positive - that it should be positioned so as to pose the least risk to permanent way workers.

 

Would that be on the left of one siding and then the left again in the next!? (To maximize distance between live track?) And would this then influence the placing of third rail of the track leading into the layout in the first place!?! 

 

Getting my brain tied up in knots trying to figure it out, any help would be greatly appreciated! 

 

 

 

 

 

 

 

Edited August 27, 2020 by Ray Von

[johnb]

See the Southern Railway E-Mail Group website https://sremg.org.uk/home.html   under Prototype Features. All you will need to know about 3rd rail

[crompton 33]

Ray This is what i've done on my southern 3rd rail layout.  Click on the pic to see more  https://www.flickr.com/photos/97097957@N06/35632894166/in/photostream/

 

[Jeremy Cumberland]

This is easily the most informative website that I know of (although I am biased towards London Underground, so I tend to ignore websites that only cover Southern or other conductor rail systems):

http://www.clag.org.uk/3rd-4th.html

 

It will show you exactly what to do with points. Note that shoes can only run on and off the end of a conductor rail, not the edges, so points almost always have a break in the rail at the switches, although side ramps are provided where gaps would create a risk of gapping. Your double slip will be a very awkward beast indeed.

 

Edit: I have just realised this is the same web page that @johnb links to (except that my link takes you straight there)

Edited August 27, 2020 by Jeremy C

[Ray Von]

22 minutes ago, Jeremy C said:

Your double slip will be a very awkward beast indeed.

 

Yes, I can't see how it'll work to be honest! :-(

[Nearholmer]

38 minutes ago, Jeremy C said:

Note that shoes can only run on and off the end of a conductor rail, not the edges,

 

That may be true of current(!) third-rail practice, but earlier practice made quite extensive use of "side ramps".

 

They were only suitable for slow-speed moves when used in the facing direction, so typically in and around station throats, because the ramp was quite steep and would knock shoes off if taken at any speed. In fact, they frequently knocked shoes off even at designed speed, which is why they are now very rare, possibly even absent altogether. Trailing side ramps are less of a problem, so can be used at higher speeds and I think remain fairly common at junctions.

 

PS: Just noticed that you do also mention side ramps.

 

I don't know how it is done now, but the final DO check on conductor rail layout designs used to involve moving a little bits of card with the shoe-spacings marked out to scale along all the possible routes on a scale drawing of the layout, so don't feel embarrassed if you have to resort to the same thing to get it right!

 

 

Edited August 27, 2020 by Nearholmer

[34theletterbetweenB&D]

On ‎27‎/‎08‎/‎2020 at 21:57, Jeremy C said:

... Your double slip will be a very awkward beast indeed...

 

On ‎27‎/‎08‎/‎2020 at 22:20, Ray Von said:

Yes, I can't see how it'll work to be honest!

As a grossly underscale piece of track, it's basically impossible. But to the inexpert observer, whether you parallel the outside curves with continuous conductor rail, or have the conductor rail ramps on the straight approaches leaving the bulk of slip as a large gapped section, it won't matter: the effort of having the conductor rail is what will be observed. And those that have the knowledge should understand that compromise is inevitable.

[Ray Von]

On 27/08/2020 at 21:57, Jeremy C said:

Note that shoes can only run on and off the end of a conductor rail, not the edges, so points almost always have a break in the rail at the switches, although side ramps are provided where gaps would create a risk of gapping.

Just found a nice pic of that very thing! 

[Grovenor]

I can't see any side ramps in that picture, all the third rail stops short of the switch zone where side ramps would be.

[Ray Von]

37 minutes ago, Grovenor said:

I can't see any side ramps in that picture, all the third rail stops short of the switch zone where side ramps would be.

That's my point (no pun intended) - I'm glad that there are some real world examples that I can take inspiration from. 

Struggling to find images of Side Ramps in fact....

[Grovenor]

Several pictures of side ramps on the CLAG site linked above, quite a long way down the page!

[Gwiwer]

Until around the mid 1970s side ramps were in general use.  As line speeds increased and technology advanced (including having lighter weight pick-up shoes) these became obsolete and present day practice is to install short lengths of "plain" conductor rail as and where possible.

 

Placement through points and switches must minimise the risk of "gapping" which would occur if all the shoes were off the juice at the same moment.  That can cause a train to stall and require assistance which in turn will also cause timetable chaos.  

 

Review as many images as you can find of pointwork to see what works best in your situation.  The double-slip would have - at the most - just a couple of short lengths of conductor rail around the curved sides but positioned such that trains running straight through would not make any contact with them.  Or, for older time periods, a continuous (if possible) conductor rail around one curve with side ramps to allow safe passage of pick-up shoes when trains take the opposite route.  

 

You are correct in placing the conductor rail on the far side of the track away from the platform edge.  While this is normal it cannot be done in all locations meaning you will find some platforms with conductor rail adjacent to them.  This is of necessity the case when one track is served by two platforms one on either side.  There are specific safety instructions for staff to follow when working in such locations.  

 

Third rail in yards and sidings must be protected with wooden boards either side and should be fitted on the side of least risk allowing for required stock movements.  Inside sheds there are no conductors rail - trains are powered from plug-in overhead cables.  

 

[Dagworth]

16 minutes ago, Gwiwer said:

Inside sheds there are no conductors rail - trains are powered from plug-in overhead cables.  

Not always, Grove Park, Victoria downside shed (can't remember its proper name) and Addiscombe sheds had third rail inside the sheds. It tended to be maintenance shed that had overhead feeds.

 

Andi

Edited August 30, 2020 by Dagworth

[Gwiwer]

10 minutes ago, Dagworth said:

Victoria downside shed (can't remember its proper name)

Grosvenor

Quote

It tended to be maintenance shed that had overhead feeds.

Correct.  I should have been more specific.  Most berthing locations had conductor rail the length of the sheds.  There were numerous of these; West Worthing and Littlehampton were two more.  

Edited August 30, 2020 by Gwiwer