Mid-Cornwall Lines - 1950s Western Region in 00

[KingEdwardII]

2 hours ago, St Enodoc said:

use a spare Cobalt iP Analogue point motor ... - in effect a power-operated DPDT switch

I'd use a MTB MP5 point motor for that purpose since it has a pair of built-in switches.

 

I very much agree with you concerning the avoidance of short circuits on the layout - I always prefer direct switching of frog polarity from the point motor rather than the use of frog juicers.

 

Yours,  Mike.

[St Enodoc]

Just now, KingEdwardII said:

I'd use a MTB MP5 point motor for that purpose since it has a pair of built-in switches.

 

I very much agree with you concerning the avoidance of short circuits on the layout - I always prefer direct switching of frog polarity from the point motor rather than the use of frog juicers.

 

Yours,  Mike.

Yes but I haven't got one of those!

 

I need a total of three changeover switches - one for the frog on 13 points and one each for the "front" and "rear" rails at Polperran, to switch them between the red and black bus wires. Each Cobalt iP Analogue has two changeover switches so all should be well.

[5BarVT]

2 hours ago, St Enodoc said:

.the triangle, of course, needs the polarity of one of the legs to be changed to avoid short circuits. I've decided that the reversible section will be the whole of Polperran including Treloggan Junction 13 points as seen in the foreground here. I could use an electronic auto-reverser for this but a) I haven't got one and the local shops have no stock; b) I have an inbuilt aversion to creating short circuits intentionally on the layout, even if there is a reason for doing so; and c) they are not cheap.

 

Instead, I'm going to use a spare Cobalt iP Analogue point motor, wired in parallel with the one for the point itself, to reverse the polarity through its changeover switches - in effect a power-operated DPDT switch. It should work, as there will be no need for a "dynamic" polarity reversal - the point will have to be set before anything runs across it.

That’s clever!

Having started fitting out my lifting flap I’ve discovered a problem with my proposed wire routing across the hinge and thoughts had turned to frog juicers, but like you I prefer ‘simple’ electrical solutions.  I’ll retain this as a possibility.

I have one tortoise where I mangled the gears a bit but it does still throw, this could be a good use for it.

Paul.

[t-b-g]

We have done similar sort of switching on Narrow Road by using relays purchased from somewhere like RS components and using the switch on the point motor as an on/off switch for the relays.

[5BarVT]

5 minutes ago, St Enodoc said:

Each Cobalt iP Analogue has two changeover switches so all should be well.

One thought . . .

Frog switching will only be loaded by one loco at a time and not when the switch operates.  When you switch the whole of Pentowan there will be a multiple loco load at time of switching.  Good job you aren’t into sound!

Paul.

[St Enodoc]

On 20/08/2021 at 18:35, St Enodoc said:

It's a bit tricky, Baz. The way I did it was to drill out the Lima mounting hole, fit a new mounting plate on top of the floor and clip the new bogies to that. If you use the original mountings the vehicle rides too high. If I remember I'll remove a bogie and take a photo.

Well, I shouldn't rely on memory. What I described there was how I fitted Lima Mk1s (and the LMS 42ft GUV) with 14mm wheels. On the Siphons I just chopped away large parts of the floor, so the wheels would fit, and use a screw to fix the Bachmann bogies to the original bogie mountings.

[St Enodoc]

16 minutes ago, 5BarVT said:

One thought . . .

Frog switching will only be loaded by one loco at a time and not when the switch operates.  When you switch the whole of Pentowan there will be a multiple loco load at time of switching.  Good job you aren’t into sound!

Paul.

That's one of the reasons why I decided to do it at Polperran not Pentowan, Paul. At Polperran there will only ever be one train in action at a time and the quiescent current draw of non-sound and non-lighted trains is negligible. The Cobalt switches are rated at 5A continuous so they should be able to cope with making and breaking the tiny current, especially as it's a form of ac not dc.

 

If not, I'll have to swallow my pride and get a solid-state auto-reverser or use a relay as Tony @t-b-gmentioned.

Edited August 21, 2021 by St Enodoc

[Chamby]

1 hour ago, t-b-g said:

We have done similar sort of switching on Narrow Road by using relays purchased from somewhere like RS components and using the switch on the point motor as an on/off switch for the relays.

 

Lots of ways to achieve this.  My first approach would be a changeover microswitch fixed to, and activated by the point motor...

[t-b-g]

1 hour ago, Chamby said:

 

Lots of ways to achieve this.  My first approach would be a changeover microswitch fixed to, and activated by the point motor...

Indeed there are. We needed some switching which could be activated by throwing more than one point, such as activating either end of a loop. The loop was fed via a relay which was switched on by the auxiliary switch on the motor at either end. With both points "normal" the loop was isolated but to run in or out, you only had to change the point at that end and either one would work the relay and put the power on. It is a method which is perhaps not really relevant to DCC control but it can be useful for DC.

[St Enodoc]

Electrical work today, as planned.

 

First,  I installed the Terminus bus wires at the rear of the Polperran L-girders and connected them to the Terminus EB1 circuit breaker. Then I attached the droppers to all the permanently-laid track. There are two sections of plain track and two points, so a total of ten droppers altogether, including the frog droppers for the points.

 

After that, I fitted the three point motors, two for the points themselves and one close to 13 points as the polarity reverser. I connected all the the droppers except those for 13 points, where I need to work out the reverser circuit first, to the Terminus bus and once that was done I used a 9V battery to throw both points for the Loop.

 

The multimeter showed me that the track connections were correct, so I fitted temporary frog jumpers and a couple of temporary leads from Treloggan Junction to Polperran, before testing the new track and points with 4247. All good, so next weekend I should be able to finish wiring the permanent track.

 

No photos, as from the surface nothing looks very different from how it did yesterday.

[5BarVT]

1 hour ago, St Enodoc said:

Then I attached the droppers . . . ten droppers altogether

Only 10?!

But that reminded me I have droppers still to fit.

Another 12!

Paul.

On counting properly I have only 10.

Edited August 22, 2021 by 5BarVT
Counting properly.

[St Enodoc]

11 minutes ago, 5BarVT said:

Only 10?!

But that reminded me I have droppers still to fit.

Another 12!

Paul.

2+3+2+3=10...

 

Yep!

[Stubby47]

Did you realise that 10+10 is the same as 11+11?

[5BarVT]

43 minutes ago, Stubby47 said:

Did you realise that 10+10 is the same as 11+11?

Is that out of the same camp as the “I have 11 fingers” party trick?

Paul.

[Stubby47]

Nope.

 

Out loud, say "10+10 is" and give the answer.

 

Then do the same for 11+11...

[St Enodoc]

1 hour ago, Stubby47 said:

Did you realise that 10+10 is the same as 11+11?

 

Go on, I'll buy it...

 

[St Enodoc]

Just now, Stubby47 said:

Nope.

 

Out loud, say "10+10 is" and give the answer.

 

Then do the same for 11+11...

Very good. Have a gold star.

[Nick Gough]

What happened to the 'groan' button?

[drduncan]

That’s awful.

[Oldddudders]

"A Welsh exile in Kernow"

 

Says it all.

[ian]

2 hours ago, Oldddudders said:

"A Welsh exile in Kernow"

 

Says it all.

 

WIth jokes like that no wonder the Welsh exiled him.

 

He was lucky not to get lynched!

[Chamby]

I’ll have to remember that if ever I buy anything off him...

[St Enodoc]

Thoughts have turned to the Barry slip.

 

I'd already timbered-up the template and, based on my experience with the single-and double slips where space to get the cutting disc in is very tight, I gapped them all, with a file, before starting to build.

 

I've also filed up the crossing rails (but not the switches yet...).

Edited June 29, 2022 by St Enodoc
images restored

[St Enodoc]

After dinner, I filed the switches for the Barry slip then, as I was in the mood, started to put it together.

 

The crossings came first. I set the distance between the crossing noses to 165 mm using the right-angle method (16.5 x 5 x 2 = 165) and soldered in the point rail of the right-hand crossing, where all the rails are straight. Using the straight Tracksetta to align it, I then soldered the other point rail in place. I adjusted the positions of these using the Tracksetta on either side until I was happy that they were in the correct position with no (or negligible, allowing for "give") offsets between them. I think I managed this to within about 0.5mm, which should be OK.

 

The splice rails went in next, again using the straight Tracksetta at the right-hand end. However, at the other end, the exit track to Treloggan Junction is curved all the way through the crossing, so I used a combination of the straight and 30" radius Tracksettas to align this rail.

 

Next I put a set in each stock rail where the corresponding straight switch will go and tacked these in place using a combination of roller gauges and the Tracksettas. I adjusted the stock rails until I was happy a) with the gauge at the crossings; and b) that there was a smooth curve between the sets on the one hand and between the set an the curved crossing on the other. After I'd soldered all the other timbers in place I decided that that was enough for tonight.

 

Wing rails next, then switches, check rails and tiebars in the usual way.

Edited June 29, 2022 by St Enodoc
images restored

[drduncan]

I don’t think I’ve ever seen a Barry slip modelled before. Shame it’s in your fiddle yard…

D