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Single slip building help


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  • RMweb Gold

At the weekend I finally started construction of the first points for Brent, with the initial focus on a left hand C9 and a single slip connecting the up main with the branch loop. Because both points are curved I am trying to work with as long lengths of rail as possible, thus avoiding having lots of joints between short rail lengths. As part of this approach I have been forming the vee from long lengths of rail, which are then cut with the Dremmel once the track is tested in order to get the shorter ~2inch isolation lengths.

 

Thus explains the slightly odd situation shown below, with the C9 having the far rail and vee in place, while the single slip has just the far rail (attached to the C9’s vee.)

 

With this glued in position I started looking at what goes next, clearly some material needs removing from chairs to clear the slip switch blades, but even so, I cannot see enough material to fix the blades in place. At best it looks like there will only be a couple of chairs holding them in position (likewise the same will be true for the check rail). From memory I think each switch rail is about 2 inches long from the Templot drawing.

 

I would welcome some advice as to how I might achieve this, as looking at the moment I am completely lost.

 

Further to this, (despite the large red words on the template) I forgot to file on the notches for the switch blades to fit into. Is it possible to file these into a rail which has already been fitted (or will it be ok without?)

 

Hopefully will be buying a switch rail filing jig at Wells in 2 weeks time, (thus preventing much more work on the C9) So tonight’s project is to build the next vee assemblies to allow the fitting of the rest of the down mainline at the Exeter end.

 

At present my intention is that by fitting the outer rails and vee, followed by the approach and exit tracks, I can do the basic testing and prove each element as I build. Hopefully ensuring no operational issues, (though given the poor access under the layout coupled with the fixed baseboards I am dreading fitting Tortoise motors!)

post-54-0-53086200-1470062707_thumb.jpeg

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I cannot see enough material to fix the blades in place. At best it looks like there will only be a couple of chairs holding them in position (likewise the same will be true for the check rail). From memory I think each switch rail is about 2 inches long from the Templot drawing.

it is best to make the slip switch blades in one piece from end to end, ie with a blade each end of the one rail, then there should be enough chairs in the centre to hold it.

 

Further to this, (despite the large red words on the template) I forgot to file on the notches for the switch blades to fit into.

There should be no need of any notches, they are IMHO bad practice*, just file the blades to a proper knife edge so they fit snugly alongside the stockrails.

And no, I don't think it practical to file such notches in situ.

Regards

* Except with FB rail where it helps to notch the foot.

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Is this any help? It looks like a similar shape to yours.

 

post-7091-0-85169300-1470068774.jpg

 

It was sort of designed in Templot, by overlaying two straight turnouts using a Peco large radius template adjusted to EM, then printed out and the extra crossings etc drawn in by hand. I can post some close ups if they help. I've only just made it, and it seems to work, but I won't be able to test in thoroughly for a few days.

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Rich

 

I always hinge the switch rails on double slips as the tension of 2 pairs of switch blades is far too much'

 

If you think of a double ended switch blade I cut it into 3 sections and solder a C&L cast brass fishplate to both ends of the centre section, the switch blades are just a push on fit

 

post-1131-0-91590500-1470068919.jpeg

 

Cannot find the correct photos but here is a single slip where the principal is similar, I solder the centre parts of the slip to thin 0.6 mm thick copperclad

 

post-1131-0-80897700-1470070309.jpg

 

Yjis is a double slip Once its all soldered together I trim off the excess copperclad strip so its flush with the rail sides, with the single slip normally there is no need to hinge the blades. But a double slip I would have mad the cuts to the slip rails so the centre part covers the centre 5 or 7 timbers

 

post-1131-0-30593600-1470070120.jpg

 

Here is one I have found, you can just about see the joints, the centre part covers 7 timbers

 

By the way its easier to start with the Vee's first

 

 

 

 

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  • RMweb Gold

Further to this, (despite the large red words on the template) I forgot to file on the notches for the switch blades to fit into. Is it possible to file these into a rail which has already been fitted (or will it be ok without?)

 

Hi Rich,

 

It is not possible to get the correct switch geometry if you file notches in the stock rail. You need either:

 

1. plain rail on one side, and a set (bend) in the opposite stock rail, with knife-end switch blades, or

 

2. joggles in both stock rails, with stubby-end switch blades.

 

A set bend is 10 times easier to make than an accurate joggle. Likewise a knife-end blade is easier to file than a stubby-end switch blade which is exactly the right thickness at the end. More about all this here:

 

 http://templot.com/martweb/gs_realtrack.htm#joggle

 

The positions for all these things are marked on the Templot templates. I see from your photo that you have opted for joggles on the templates.

 

In theory it might be possible to replicate the geometry of a joggle by filing a notch, but it is all but impossible to do that after assembly of the rail. It is certainly impossible to make a set bend after assembly.

 

Normally in a slip the sets for the switches would be in the outer curved rail. That means they need to be in the rail which you have already fixed. They are marked on the template, because it is important to get them exactly the correct distance apart.

 

However in a situation such as this with the slip road effectively straight or curved the opposite way it might be better to swap the hand of the slip switches. It all rather depends on which road is the running line and which is a crossover road --this governs which road gets the speed restriction on the prototype. If you do swap the hand of the switches you no longer have a conventional slip and you can't design it based on an underlying diamond-crossing. Instead it needs to be created as two turnouts overlaid.

 

regards,

 

Martin.

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If you do swap the hand of the switches you no longer have a conventional slip and you can't design it based on an underlying diamond-crossing. Instead it needs to be created as two turnouts overlaid.

 

regards,

 

Martin.

As I said earlier, mine is based on two overlaid turnouts, and I used joggles where marked on the turnout plans. I wasn't aiming for prototype accuracy, and it's only a shunting layout, but it does seem to work.

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  • RMweb Gold

Thanks for the advice,

The running line in question runs from the bottom right to top left,

 

The bottom left to top right route connects the yard to the up main (usually freight)

 

The slip road was added quite late (I think 1930s) connecting the down platform to the up main, I haven't seen any workings which would use it. Does that help?

 

As for the notches, joggles etc, I think I will keep it simple!

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  • RMweb Gold

Here's a view of the real thing - reading from left to right there is the U Main Line, the Down Main Line, the Down Loop and the branch.  The slip connection forms the Main Lines trailing crossover plus a lead in from the right creating a running route from the Branch platform to the Up Main (signalled for passenger trains).

 

http://www.cornwallrailwaysociety.org.uk/uploads/7/6/8/3/7683812/4590911_orig.jpg

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  • 2 weeks later...

Here's a view of the real thing - reading from left to right there is the U Main Line, the Down Main Line, the Down Loop and the branch.  The slip connection forms the Main Lines trailing crossover plus a lead in from the right creating a running route from the Branch platform to the Up Main (signalled for passenger trains).

 

http://www.cornwallrailwaysociety.org.uk/uploads/7/6/8/3/7683812/4590911_orig.jpg

 

Hello Mike,

 

looking at the photo, if I'm reading the signals correctly. The steam loco is stopped at the 'home' peg in the loop, with the main  line peg pulled off?

 

Looking at the slip, that's looks interesting in that it has a check rail on the curved rail, then when you look at the point that runs to the loop it has a very long check rail both before the toe of the point and after the 'frog' Vee. Then when you look at the point off the up line the curved part of the point has a check rail from the switch rail. It may also have a check rail in front of (or after), the toe of the point.

 

A nice photo.

 

ATB

 

OzzyO.

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