Making a simple link

[bordercollie]

Hi
I have progressed a bit further with timber shoving. I have designed the turnout carrage siding engine shed siding TR2206 on attached file with a curviform crossing but I am not sure if generic/regular or parallel would have been better. I can not remember why I selected curviform. I don't know if it was a mistake or whether there was a good reason. The main road and carriage siding are on a curve that starts at the exit of Tr2195. It looks OK visually to me but I am not sure if it is the best solution.

 

[Martin Wynne]

@bordercollie

Hi Graham,

Where the diverging road swings back towards the main road, it is usually better to use a regular V-crossing. This minimises the effect of the reverse curving. This is especially the case where there is contraflexure in the turnout, as you have there. More info in this video:

https://flashbackconnect.com/Movie.aspx?id=pu2F-wveux5-EWGYuqPd3g2

In this case, using a curviform V-crossing, you have an instantaneous reverse (change of curving direction) at the vee joint. That wouldn't be acceptable in a running line, but for a low-speed siding connection, as here, it's not necessarily wrong:

On the other hand, changing to a regular V-crossing and making a full simple link does this,

causing the curve to extend into the Engine Shed and not fit through the shed doorway properly.

I suggest therefore using a regular V-crossing, but making the branch track dead straight. Then swap facing-trailing so that the rail-joint marker is at the free end (important), and slide the peg along it to a suitable tangency position (CTRL+F8 mouse action). Don't go too far, otherwise Templot will complain that a link curve won't fit:

You can then do make simple link on the Engine Shed track, with this result:

The branch track gets split at the peg, and a curve is fitted between the two. Leaving a reasonable length of straight track in front of the shed doors.

For these screenshots I added the Engine Shed via the sketchboard.

p.s. this is not about timber shoving, so I will move it to a separate topic shortly.

cheers,

Martin.

 

[bordercollie]

Hi Martin

I have been trying to do as you have outlined. I have changed the "V" to regular.

I have found that the best fit was to set the peg at peg 1 on branchline. If I moved the peg much further along the branchline template than a few sleepers towards engine shed road I couldn't get it to work as you have shown on your screen shot. I either got error message or at best curved the wrong way. In the attached file the top layout shows what happens if I set the peg of the branchline at the junction with the turnout. The first duplicate shows the addition of a straight branchline. The the third shows what happens if the peg is placed as shown. The fourth shows that I get a invalid request message. What am I doing wrong? Is there anything wrong with the link as shown in top group? I have tried several things but I cannot get an out come as shown in your last reply.
Regards
Graham

 

[Martin Wynne]

@bordercollie

Hi Graham,

The bit you missed is that I wrote:

Then swap facing-trailing so that the rail-joint marker is at the free end (important)

Like this:

I also extended the engine shed road so that I could see not to move the peg too far forward to leave room for the curve. The make simple link function will trim the engine shed track to fit:

When doing a simple link, Templot reads the the guide template direction from the Ctrl-0 datum end towards the Ctrl-1 joint end, so it's important to have the template the right way round -- joined to the previous template at Ctrl-0, and free end to be modified at Ctrl-1.

See also:

https://85a.uk/templot/companion/make_simple_link.php

cheers,

Martin.

 

[Martin Wynne]

@bordercollie

p.s. Graham,

To avoid confusion I have now changed the button to read "facing-trailng" when there is a turnout in the control template, and "swap ends" when it is plain track or a half-diamond:

Will be in 227b soon.

cheers,

Martin.

 

[bordercollie]

Hi Martin
I have finally got it to work. I had swapped end for end in my previous attempts. However, my understanding of what you were describing was a bit off the mark. Now, having achieved a link as you described I was wondering if there is anything wrong with having a a continuous curve from the engine shed and turnout templates i.e. the top track plan on my original attachment. Would it make the timber shoving at turnout/ plain track junction easier. From your previous replies I can see that there was probably no preferred/prescribed way of doing things laid down by railway companies at the time, particularly in a siding situation.
Regards
Graham