Mid-Cornwall Lines - 1950s Western Region in 00

[aardvark]

22 hours ago, Clive Mortimore said:

You will be planting trees next.

 

 

Or telegraph poles.

 

Same thing, but "poles" are more advanced.

[Oldddudders]

1 hour ago, aardvark said:

 

Same thing, but "poles" are more advanced.

And were welcome in a pre-Brexit era.

 

There was a Pole who lived near us in my yoof. He had a shack the other side of Brockham Crossing. And he really was called Felix, which takes us back to GWR days! 

[St Enodoc]

11 minutes ago, Oldddudders said:

And were welcome in a pre-Brexit era.

 

There was a Pole who lived near us in my yoof. He had a shack the other side of Brockham Crossing. And he really was called Felix, which takes us back to GWR days! 

Brockham Crossing...

 

In about 1984 a couple of dozen sheep escaped on to the line there and derailed a DMU. What a mess.

[Oldddudders]

9 minutes ago, St Enodoc said:

Brockham Crossing...

 

In about 1984 a couple of dozen sheep escaped on to the line there and derailed a DMU. What a mess.

How horrid. We moved from our tied cottage nearby 2.5.miles to a detached house in Deepdene Vale in 1965. In the '70s Deepdene station was the scene of more than one high-speed derailment of a stone train. 

[St Enodoc]

On 06/09/2020 at 08:32, St Enodoc said:

You're trying very hard to talk me into it!

 

Yes, I could change the route setting. It would mean setting up a command station macro for probably two or three more routes than just the few that already need five or more commands at the moment (the NCE Mini Panel is limited to four steps per input).

 

I'll have a think...

I think it can be done...

 

There are 14 routes at Paddington Down end that will be affected:

 

- the Bypass, that lets trains run in the Up direction right round to Penzance via loop 1 (route 14);

- the twelve loops 2 - 13 themselves (routes 15 - 26); and

- the Tregissey siding itself (route 30).

 

When route 26 (loop 13) is set, the final point 208 is Reversed; and when route 30 (Tregissey siding) is set, the final point 216 is Reversed.

 

Hence, to make sure that the Trewoon Junction Up Main Distant stays On when either route 26 or 30 is selected, I need to connect the feed to its actuator through the changeover switches on points 208 and 216 in series, so that the circuit is completed only when both points are Normal.

 

That means that whenever route 26 is not set, point 208 must be Normal; and whenever route 30 is not set, point 216 must be Normal. I can do this by adding one or more extra steps to each of routes 14 - 26 and 30. However, because some of these routes already have the maximum number of four steps assigned to their Mini Panel inputs, I will need to convert some of the steps to command station macros. Not a difficult task but I think I'll leave it until the signals I installed yesterday are wired up and working.

 

As a refinement, while I'm at it, I might also route the feed through point 213, which is the Y-point that connects the loops to either of the Up or Down lines. That would ensure that the signal only comes Off for Up trains, irrespective of the position of the "From Porthmellyn Road" Line Clear Release switch.

 

Paul (5BarVT), you owe me a pint...

 

 

[5BarVT]

I do like setting challenges!

Leave it for later definitely sounds best.  I like the addition of ‘Up Trains only’.

Paul.

[St Enodoc]

20 minutes ago, 5BarVT said:

I do like setting challenges!

Leave it for later definitely sounds best.  I like the addition of ‘Up Trains only’.

Paul.

Thanks Paul. It shouldn't be hard to do, only about an hour's work, but I'm part-way through getting the other signals working so I want to finish that first.

[Stubby47]

If you were to put the signal beyond the scenic break, I'm sure it would be a lot simpler.

[5BarVT]

1 hour ago, Stubby47 said:

If you were to put the signal beyond the scenic break, I'm sure it would be a lot simpler.

Where’s the fun in that!

:-)

Paul.

[Keith Addenbrooke]

46 minutes ago, 5BarVT said:

Where’s the fun in that!

:-)

Paul.

 

Fitting the brackets / signal arm extensions so the driver can see the signal through the 'tunnel'?

 

Or did I misunderstand the suggestion...

[St Enodoc]

The memory wire actuators, as built, need a current of about 200 to 250mA to heat the wire enough, but not too much, to contract fully. A 1.5V battery, as used on the distant signal, provides this but it isn't really practicable to provide a separate battery for every signal. Instead, I use a simple current regulator made up using an LM317 voltage regulator chip. Now, as the name implies, these are normally intended as voltage regulators but if you wire the Input, Output and Adjust terminals in a particular configuration they act as current regulators. Here is the circuit:

 

The value of the resistor determines the output current which stays constant irrespective of load for input voltages of about 3 - 40V dc. A 5.6 ohm resistor gives an output current of about 220mA and will dissipate about 0.28W so a good chunky wire-wound type is best. It's a good idea to use a heat sink to mount the LM317T as well.

 

Obviously, as a mechanical engineer, I didn't work this out for myself of course - I found the details here:

 

http://www.reuk.co.uk/wordpress/lighting/using-the-lm317t-with-led-lighting/

 

The capacitor probably isn't really needed but it is shown on other reference sources as an input filter, so for the sake of an extra 50c I added it.

 

On the previous St Enodoc layout I supplied these regulators direct through the PO key switches but the Modratec lever frame switches are limited to a current of 100mA, so I'll use a relay to control a separate 12V dc supply to the regulator.

 

I've mocked this up on the desk and I'll build the first ones at the weekend, using some of the existing regulators recovered when I dismantled the last layout.

Edited July 17, 2023 by St Enodoc
images restored

[St Enodoc]

On 07/09/2020 at 16:53, aardvark said:

 

Same thing, but "poles" are more advanced.

I was at an athletics meeting once when I saw a chap coming the other way with a long stick over his shoulder.

 

"Ah, you must be a pole vaulter" I said.

 

"No", he replied. "I'm German, actually, but how did you know my name was Walter?"

 

I thank you.

[acg5324]

6 hours ago, St Enodoc said:

I was at an athletics meeting once when I saw a chap coming the other way with a long stick over his shoulder.

 

"Ah, you must be a pole vaulter" I said.

 

"No", he replied. "I'm German, actually, but how did you know my name was Walter?"

 

I thank you.

There’s never a groan button when you want one. 

[gwrrob]

5 minutes ago, acg5324 said:

There’s never a groan button when you want one. 

 

[aardvark]

11 hours ago, St Enodoc said:

I was at an athletics meeting once when I saw a chap coming the other way with a long stick over his shoulder.

 

"Ah, you must be a pole vaulter" I said.

 

"No", he replied. "I'm German, actually, but how did you know my name was Walter?"

 

I thank you.

 

Reminds me of the tourist visiting the US Pacific island state, and being unsure of whether it was pronouced Ha-why-ee or Ha-vie-ee, so asked a passer-by, who said it was Ha-vie-ee.  The tourist thanked the passer-by, who said ... "You're velcome."

 

 

Edited September 9, 2020 by aardvark
typos - always typos

[Stubby47]

Have just discovered one of my great grandmothers was born in Hawaii,  making me slightly American.

[St Enodoc]

1 hour ago, Stubby47 said:

Have just discovered one of my great grandmothers was born in Hawaii,  making me slightly American.

Why did California?

She called to say Hawaii.

 

etc., etc.

[Oldddudders]

How did Wisconsin, boy? Stole a Newbrasskey etc etc. 

[bgman]

2 hours ago, Stubby47 said:

Have just discovered one of my great grandmothers was born in Hawaii,  making me slightly American.

 

All the more reason to wear a flowery shirt at Staplegrove ( when it returns ! ) 

Not certain about being from over the pond though ??? I feel a Kernow / Welsh / American twang coming on but please don't accent-uate

[St Enodoc]

20 minutes ago, bgman said:

please don't accent-uate

But according to Johnny Mercer we must always accent-uate the positive.

[Barry O]

23 hours ago, St Enodoc said:

The memory wire actuators, as built, need a current of about 200 to 250mA to heat the wire enough, but not too much, to contract fully. A 1.5V battery, as used on the distant signal, provides this but it isn't really practicable to provide a separate battery for every signal. Instead, I use a simple current regulator made up using an LM317 voltage regulator chip. Now, as the name implies, these are normally intended as voltage regulators but if you wire the Input, Output and Adjust terminals in a particular configuration they act as current regulators. Here is the circuit:

 

The value of the resistor determines the output current which stays constant irrespective of load for input voltages of about 3 - 40V dc. A 5.6 ohm resistor gives an output current of about 220mA and will dissipate about 0.28W so a good chunky wire-wound type is best. It's a good idea to use a heat sink to mount the LM317T as well.

 

Obviously, as a mechanical engineer, I didn't work this out for myself of course - I found the details here:

 

http://www.reuk.co.uk/wordpress/lighting/using-the-lm317t-with-led-lighting/

 

The capacitor probably isn't really needed but it is shown on other reference sources as an input filter, so for the sake of an extra 50c I added it.

 

On the previous St Enodoc layout I supplied these regulators direct through the PO key switches but the Modratec lever frame switches are limited to a current of 100mA, so I'll use a relay to control a separate 12V dc supply to the regulator.

 

I've mocked this up on the desk and I'll build the first ones at the weekend, using some of the existing regulators recovered when I dismantled the last layout.

Always good to have a decoupling capacitor .. some circuits "designed" by experts  can be very "noisy" - some servo drivers can be susceptible to such noise...

 

Baz

[St Enodoc]

Just now, Barry O said:

Always good to have a decoupling capacitor .. some circuits "designed" by experts  can be very "noisy" - some servo drivers can be susceptible to such noise...

 

Baz

Thanks Baz. I've no idea really what it's called or why it's there but somebody told me I should have one so there it is. Just a small tantalum jobby.

[acg5324]

7 hours ago, St Enodoc said:

Why did California?

She called to say Hawaii.

 

etc., etc.

I’ve just arrived from Hawaii.......

Honalulu? 

No on a surf board!

 

I’ll get my coat.........

[St Enodoc]

5 hours ago, acg5324 said:

I’ve just arrived from Hawaii.......

Honalulu? 

No on a surf board!

 

I’ll get my coat.........

Ah, the old one are the best - aren't we...

[Stubby47]

On ‎10‎/‎09‎/‎2020 at 07:47, Stubby47 said:

Have just discovered one of my great grandmothers was born in Hawaii,  making me slightly American.

 

Update.

 

As great-grandmother was born in 1873, the Sandwich Islands were not part of the US of A at that time, so I'm part Hawaiian, but not part American.

 

Edited September 11, 2020 by Stubby47