Tandem build query - Crossing angles

[RobA2345]

I should have maybe asked this before I commenced the build but can someone please confirm these crossings are in the correct place as the instructions supplied are just standard turnout instructions. The kit is for a 1:8 RH 1:6 RH tandem turnout and 3 crossings were supplied at 1:5 1:6 & 1:8 angles. I only have the template to go off and looking at the angles have placed them as per the below image, is this correct? 
 

If so the 1:6 crossing on the approach is way out as per the second image, is this something to be worried about? Is there any corrective action I could or should be taking?

[RobA2345]

I think I may have answered my own question but the crossing didn't work anyway as I'd installed the curved stock rail only relative to the V on the 1:5 crossing when really the 1:6 crossing needed installing as well before the curved stock rail to accurately gauge across its position. The rails are starting to be a good couple of mm out from the template now the further I move across but its obviously more important the gauge standard is accurate than following the template.

[ikcdab]

I used to use this sort of template but also found them not to be accurate. i think (and I stand to be corrected) that they were originally hand-drawn and have been repeatedly copied. inevitably distortions have crept in. in this case, its more important that the rails are correctly gauged and line-up rather then following the template slavishly.

The only truly accurate template i have found are from templot. Those you could almost build the turnout without any gauges at all (though I don't recommend it!)

[RobA2345]

50 minutes ago, ikcdab said:

I used to use this sort of template but also found them not to be accurate. i think (and I stand to be corrected) that they were originally hand-drawn and have been repeatedly copied. inevitably distortions have crept in. in this case, its more important that the rails are correctly gauged and line-up rather then following the template slavishly.

The only truly accurate template i have found are from templot. Those you could almost build the turnout without any gauges at all (though I don't recommend it!)

Thanks yes that makes sense. I'm okay with Templot but not a power user by any stretch and I've tried to configure a tandem but there's a bit more to them and didn't really trust the geometry of the ones I created.

 

I've made some more progress anyway and my test wagon passes the two back to back crossings so I just need to be careful to constantly check and recheck gauges as I go.

[martin_wynne]

Hi Rob,

 

I think you have the supplied 1:6 and 1:8 V-crossings mixed up. In a single-sided tandem the middle V-crossing is normally the flattest of the three.

 

The first two also need to be curviform, rather than straight-over-straight as probably supplied. You can probably modify them by bending.

 

If your kit is labelled 1:6 & 1:8, a typical single-sided tandem in EM would be  1:6, 1:9-ish, 1:8 in that order, like this:

 

 

It seems you have been supplied with a 1:5 crossing in error. It should have been a 1:9.

 

Or for a shorter tandem, maybe 1:5.5, 1:9, 1:6 like this:

 

 

cheers,

 

Martin.

Edited April 6, 2021 by martin_wynne

[RobA2345]

Yikes if that's correct then my attempt is completely wrong. To be more specific I ordered the 1:6 R/H 1:8 R/H 3 way turnout. When following the supplied template the 1:8 crossing fit the last crossing which is why I placed it there. I did think something was off with the crossings not being curved and did attempt to bend them but one of solderings on the crossing came loose so my strategy was to cut the wing and V rails quite short to curve the joining rails that it would be somewhat disguised. 

 

I guess the question now then is do I start over. Would the turnout not work if I left the crossings where they are?

[martin_wynne]

22 minutes ago, RobA2345 said:

Would the turnout not work if I left the crossings where they are?

 

Hi Rob,

 

It will work if:

 

1. all the crossings are properly checked opposite the knuckle gaps, and

 

2. the check gauge is everywhere correct (17.2mm min), and

 

3. the track gauge is nowhere less than 18.2mm.

 

A few slight dog-legs where the crossing angles are not exactly correct doesn't matter within reason (and is prototypical in yards and sidings).

 

Here is a scan of an original Protofour template, drawn by Bernard Weller in the 1960s:

 

 

cheers,

 

Martin.

[RobA2345]

Thanks Martin that’s super helpful.

[RobA2345]

@martin_wynne I'm going to be pulling up my track at some point so I'll be taking the opportunity to correct the turnout discussed above. Are there instructions so I can recreate the steps you've done to create the 1:6-1:9-1:8 example above? If not would it be possible to list them here if they're simple enough?

C&L don't supply curviform crossings so I'll need to manipulate the stock ones by bending them.