Opinions please...

[jpendle]

Hi,

I just tried to do this with one of my Tortoise motors and it just doesn't work, at least not for N Gauge.

Assuming that the Cobalt works on the same principle as the Tortoise then the first thing to get you head around is that for a regular installation the top of the actuating wire describes an arc as it moves from side to side. This is fine when you use the central hole of the fulcrum because you set the point for one route or the other, and then trim the wire so that the absolute minimum is poking through the tiebar, this ensures that any ladders, or pipes or other dangly bits on your rolling stock don't foul the wire. In my experience this means that the wire has to be no higher than the little 'pip' on a Peco point.

As the point motor moves the top of the wire will rise higher as it describes it arc as the motor is moving and then when the point is at the end of the movement the wire will have lowered again and all will be well.

So, what happens when you put a right angle bend towards the end of the wire to get to an offset point. The arc that the end of te wire becomes much greater AND you get a situation where the wire protrudes through the tie bar a lot more in one position than in the other.

Using your diagram as an exaggerated example.

The top right hand side is the bit poking through the tie bar and the tie bar is all the way over to the right hand side, the pivot point, or centre of the arc is the bottom left of the drawing. Imagine the Cobalt turning the wire about the pivot point, the bit that pokes through the tie bar will rise and rise as the point moves and will end up higher even when the point has finished moving.

What I saw yesterday when I tried this was that the wire ended up protruding by almost 0.5 cm, or around 3 to 4 times the height of the pip on the tiebar and all the rolling stock I tried fouled it.

So to fix this I'm going to try to extend the tie bar of the point, and if that doesn't work I'm going to have to attack the baseboard framework to make room for a centrally placed motor.

As a last resort I would have to lift all the track at the North end of Wigan NW station and push it all another 3 or 4 inches away from the baseboard join.

Regards,

John P

[emjaybee]

Hi JP, sorry for your turnout troubles.

This scenario had occurred to me. I've got a reasonably good eye for levers, fulcrums and pivots. I do, however have an idea, which may, or may not help you and I.

If the motor were mounted a little FARTHER away, and the top bar of the linkage was longer, you could then pass it through a couple of small eyelets which would keep it parallel with the under side of the board. This would mean that the final upright part of the linkage would remain in one plane (?). The extra length on the top bar would allow a little more flex to prevent, hopefully, the mechanism binding.

What do you think?

[LASteve]

I know you won't like this - but I think you're chasing your losses, JP.

It's painful, but I've been down those roads before and the eventual conclusion is not to work around the problem, but fix it at the source. I've spent far too many hours trying to McGuiver something that is inherently flawed.

Good luck if you can fix it, but my gut feeling is that you need to go back to basics and fix the issue before it becomes a problem.

[jpendle]

Hi,

I decided to cut a chunk out of the baseboard frame to get the motor to sit in the correct position underneath the point. It took about an hour of drilling and chiseling but the point now works as it should.

Today I just need to add some reinforcement to the baseboard frame and I will be done.

Regards,

John P

[emjaybee]

@jpendle don't cut any more baseboard!

I've had an efipany ipoofy epipyfy bright idea!

This is the usual arrangement of the actuating rod.



All my thinking has been about bending the rod above the fulcrum, that's a mistake unless you need a really big offset.

If you only need a 10mm or so offset, than I think this is the answer, using one of the other holes in the fulcrum bar.



This, I think, will solve the one problematic turnout I have to deal with.